A comprehensive review on traditional uses, chemical compositions, pharmacology properties and toxicology of Tetrastigma hemsleyanum.

ETHNOPHARMACOLOGICAL RELEVANCE: Tetrastigma hemsleyanum Diels et Gilg (T.hemsleyanum), a rare herbal plant distributed in subtropical areas of mainland China, has become a focus of scientific attention in recent years because of its high traditional value, including uses for treatment of children with fever, pneumonia, asthma, rheumatism, hepatitis, menstrual disorders, scrofula, and pharynx pain. AIM: This systematic review aims to provide an insightful understanding of traditional uses, chemical composition, pharmacological effect and clinical application of T. hemsleyanum, and lay a foundation for the further study and for the utilization of T. hemsleyanum resource.
MATERIALS AND METHODS: A domestic and overseas literature search in known databases was conducted for published articles using the relevant keywords.
RESULTS: One hundred and forty-two chemical constituents identified from T. hemsleyanum have been reported, including flavonoids, phenolic acids, polysaccharide, organic acids, fatty acids, terpenoids, steroids, amino acid and others. Among these components, flavonoids and polysaccharides were the representative active ingredients of T. hemsleyanum, which have been widely investigated. Modern pharmacological studies have shown that these components exhibited various pharmacological activities, such as anti-inflammatory, antioxidant, antivirus, antitumor, antipyretic, anti-hepatic injury, immunomodulatory, antibacterial etc. Moreover, different toxicological studies indicated that the clinical dosage of T. hemsleyanum was safe and reliable.
CONCLUSIONS: Modern pharmacological studies have well supported and clarified some traditional uses, and T. hemsleyanum has a good prospect for the development of new drugs due to these outstanding properties. However, the present findings did not provide an in-depth evaluation of bioactivity of the extracts, the composition of its active extracts was not clear. Moreover, they were insufficient to satisfactorily explain some mechanisms of action. Data regarding many aspects of T. hemsleyanum, such as links between the traditional uses and bioactivities, pharmacokinetics, quality control standard and the clinical value of active compositions is still limited which need more attention.

Tetrastigma hemsleyanum Diels et Gilg

Traditional Chinese Medicine

Ultra high performance liquid chromatography tandem triple quadrupole time of flight mass spectrometry

minimum inhibitory concentration

glutathione

malondialdehyde

nuclear factor-κB

5-hydroxytryptamine

norepinephrine

dopamine

prostaglandin E2

mitogen-activated protein kinase

lipopolysaccharide

Caenorhabditis elegans

tumor necrosis factor-alpha

interleukin-1 beta

interleukin 6

interleukin 12 subunit p40

soluble TNF receptors 1

interleukin 10

interleukin 1

interleukin 4

inducible NO synthase

Toll-like receptor 4

myeloid differentiation factor-2

myeloid differentiation protein 88

c-Jun N-terminal kinase

glutamic-pyruvic transaminase

glutamic-oxalacetic transaminase

alkaline phosphatase

superoxide dismutase

alanine aminotransferase

aspartate aminotransferase

hyaluronan

laminin

total bilirubin

total protein

interferon-gamma

immunoglobulin A

secretory immunoglobulin A

Epithelial-mesenchymal transition

matrix metalloproteinase

matrix-metallo proteinase

Cytochrome c

catalase

glutathione peroxidase

regulatory T cells

transforming growth factor beta

cyclooxygenase 2

forkhead/winged helix transcription factor gene

population doubling time

total antioxidant capacity

carbon tetrachloride

chicken embryo fibroblast

Hemagglutinating virus of Japan

vesicular stomatitis virus

alkali-containing extract of T. hemsleyanum

ketone-containing extract of T. hemsleyanum

crude extract of T. hemsleyanum

crude extract of T. hemsleyanum

Petroleum ether extractions of T. hemsleyanum ethanol extract

Chloroform extractions of T. hemsleyanum ethanol extract

ethyl acetate extractions of T. hemsleyanum ethanol extract

n-butanol extractions of T. hemsleyanum ethanol extract

Introduction

Tetrastigma hemsleyanum Diels et Gilg (T. hemsleyanum), mostly known as “San ye qing”, is a kind of folk plant. Because of its slow growth, it usually takes 3–5 years to meet the requirements of commercial medicinal materials, so it is a precious perennial medicinal resource. It mainly grows in the eastern, central, southern and south-western provinces of China, such as Zhejiang, Jiangsu Guangxi, Fujian and Yunnan provinces (Peng and Wang, 2018). T. hemsleyanum is known worldwide as sources of phytotherapeutics, which have been used for the treatment of conditions related to inflammatory and immune response, and been recorded based on clinical trials or the use of animal models (Xu, 2006). As an edible plant, the leaves of T. hemsleyanum consumed as a functional tea or dietary supplement for its health benefits, such as improving the immune system of the body (Sun et al., 2013), while the aerial parts of T. hemsleyanum developed as potential new traditional chinese medicine (TCM) preparations (Guo et al., 2019). The root tubers of T. hemsleyanum are extensively used either alone or in combination with other herbal medicines in TCM clinics for the treatment of children with fever, convulsion, pneumonia, asthma, rheumatism, hepatitis, menstrual disorders, scrofula, and pharynx pain (Sun et al., 2015; Chen and Guo, 2012). Therefore, it was called as “natural plant antibiotic” according to its wide spectrum of prominent bactericidal and anti-inflammatory activities. In February 2018, T. hemsleyanum was awarded as the new “eight famous kinds of TCM in Zhejiang province”, meant that it has become a key object of industrialization development of Zhejiang's dominant large varieties of medicinal materials.

In 2019, COVID-19 broke out and has caused more than 4600 deaths in China, and infection cases have been reported in more than 200 countries. Hua Shi Xuan Fei mixture (Approval number of Zhejiang medicine, Z20200026000), which is mainly composed of T. hemsleyanum, has been approved by Zhejiang Provincial Drug Administration for clinical treatment of COVID-19. Futhermore, the modern pharmacological studies had shown that T. hemsleyanum also had effects of anti-inflammatory (Ji et al., 2019), antioxidant (Hossain et al., 2011), antivirus (Ding et al., 2019), antitumor (Lin et al., 2014) antipyretic (Yang and Wang, 2014), anti-hepatic injury (Ma et al., 2012), immunomodulatory (Xu et al., 2008), anti-bacterial (Chen et al., 2019), hypoglycemic (Ru et al., 2018a, Ru et al., 2018b) etc. Numerous reports have demonstrated that the biological activities of T. hemsleyanum are attributed to its many chemical components (Fu et al., 2019). Wang has reported isolated alkaloids from the aerial parts of T. hemsleyanum (Wang et al., 2018). Ru extracted a novel polysaccharide TDGP-3 from T. hemsleyanum with a molecular weight of 3.31 × 105 Da by enzymolysis-ultrasonic assisted extraction method (Ru et al., 2019a, Ru et al., 2019b). Large amounts of flavonoids were found in leaves, aerial parts and root tubers of T. hemsleyanum (Xu et al., 2014a, Xu et al., 2014b; Deng et al., 2018; Yu et al., 2016). In addition, T. hemsleyanum also contains a variety of functional components, such as organic acids (Hu et al., 2013), phenolic acids (Liu, 2000), minerals (Fan et al., 2017), amino acids (Fu et al., 2015) etc.

In recent years, wild resources of T. hemsleyanum have been overexploited and now are on the verge of extinction due to its multiple medicinal values coupled with the strict requirements of the growing environments. In 2011, it was listed in the preferentially protected crop germplasm resources of Zhejiang province. Based on our team's preliminary research (Peng et al., 2013, 2015, 2016, 2019; Peng et al., 2016a, Peng et al., 2016b; Li et al., 2019), we comprehensively summarized and analyzed the domestic and overseas research progress on traditional uses, the bioactive components of T. hemsleyanum, pharmacological activities, toxicology with the aim of providing guidance for in-depth research and reference for its development and utilization.

Materials and methods

The available information about the traditional uses, phytochemicals and pharmacological properties of T. hemsleyanum was searched via Web of Science, Google Scholar, PubMed, Science Direct, China National Knowledge Infrastructure (CNKI), and Springer search using Chinese or English as the retrieval languages. The keywords used include T. hemsleyanum, root tubers of T. hemsleyanum, Radix Tetrastigma, traditional uses, phytochemistry, bioactive components, pharmacological activities, toxicology, and other related words. All references were from experimental studies and published prior to April 2020 were reviewed. All chemical structures were drawn using ChemDraw Pro 7.0 software.

Botanical characteristics

T. hemsleyanum is a perennial grass climbing vine with longitudinal ribs, glabrous or sparsely pilose. It is usually grown in a cool and humid environment, and the main soil type is yellow soil or yellow brown soil with rich humus. The optimum pH is between 4.29 and 7.65. The root tubers are thick, spindle shaped or elliptical, and single or several are connected into a string of beads, generally 1.5–3 cm long and 0.7–1.5 cm in diameter (Fig. 1 ). The epidermis of the root tubers is tan, and most of them are smooth, a few of them have folds and lenticel like protuberances, some of them have depressions, in which there are residual tan roots, hard and brittle, with a flat and rough section. The stem of T. hemsleyanum is thin and weak with longitudinal rhombus, rooting on the lower node. Palmate compound leaves alternate, leaflets are lanceolate, oblong or ovate lanceolate. The leaflets are 3–10 cm long and 1.5–3 cm wide, with a tapered tip and a wedge-shaped or round base. The flowers of T. hemsleyanum are small, yellow green and ovate. The flowering stage of T. hemsleyanum ranges from April to June, and the fruit phase is normally from August to November. When the flower withered, it will form a small green round fruit with the size of millet. When it is mature, the fruit will turn from green to red, the berries are spherical and soft spherical.

Fig. 1

The aerial part (A), root tuber (B) and raw herb (C) of T. hemsleyanum.

Traditional uses

T. hemsleyanum, belonging to the family Vitaceae, was firstly recorded in Ben Cao Gang Mu (Ming Dynasty, A.D. 1590). The aliases of Sanyeqing include Shi Hou Zi, Shi Bao Zi, Shi Lao Shu, Lan Shan Hu, Lei Dan Zi, Po Shi Zhu, Tu Jing Wan, Sou Jia Feng, San Ye Dui, golden wire hanging gourd, golden bell, golden wire hanging potato, etc. The root tubers or whole grass of T. hemsleyanum traditionally and ethnically used as a medicine for a long time, it has been recorded in multiple ancient books of TCM, such as Zhi Wu Ming Shi Tu Kao (Qing Dynasty, Wu, 2014), Jiangxi herbal medicine, Common folk herbal medicine in Zhejiang. All of these ancient works described the effects of T. hemsleyanum were heat-clearing, toxicity-removing, dyspnea-relieving, promoting blood circulation and pain relief, thus, it can be applied to cure febrile convulsion, pneumonia, bronchitis, pharyngitis, sore throat, acute and chronic hepatitis, rheumatic arthralgia, viral meningitis, bruise, eczema, insect and snake bite, poor joint flexure and extension, irregular menstruation of women (National compilation team of Chinese herbal medicine, 1975). In the TCM culture, the properties of T. hemsleyanum was described as bitter and acrid in taste, cool in nature which recorded in dictionaries of traditional Chinese medicine and Zhong Hua Ben Cao (Shanghai Science and Technology Press, 1999). The channel tropism was lung, heart, liver and kidney meridians.

Decocting with water or mashing for external application are the traditional possess methods of T. hemsleyanum. Considering its extensive traditional effects, many prescriptions containing T. hemsleyanum have been passed down from generation to generation, and have been well supported and clarified by modern pharmacological studies. Excitingly, it has reported that Jinlian disinfection drink containing san ye qing combined with interferon can treat Covid-19 (He et al., 2020). Jinqi Tablet, made up of san ye qing, astragalus and ginsenoside, was used to treat 120 cases of malignant tumor, 52 cases were completely relieved, 42 cases were partially relieved, the total effective rate was 78.33% (Wei et al., 2007). Moreover, Zhonggan mixture, including san ye qing, could improve the quality of life and prolong the survival time of patients with stage Ⅲ primary liver cancer (Jiang and Gong, 2005). In addition, it has been used in the treatment of common gynecological diseases such as blood avalanche and leucorrhea (Gao, 2004), and it also has a good effect on measles complicated with pneumonia, anal fissure, chronic bronchitis and mosquito bites (Ji, 2010).

Chemical compounds of T.hemsleyanum

The chemical constituents of T. hemsleyanum have been widely investigated (Sun, 2018; Sun et al., 2018; Zeng et al., 2017; Xu et al., 2014a, Xu et al., 2014b; Fu et al., 2015; Fan et al., 2016; Chen, 2014; Ding et al., 2015a, Ding et al., 2015b; Ding et al., 2015), a total of one hundred and forty-two compounds have been isolated and identified from T. hemsleyanum until now. The information about compound name, molecular weight, compound formula, detection method, analysis sample is summarized in Table 1 .

Table 1

The prescriptions and traditional uses of T. hemsleyanum in China.

Prescriptions name	Main composition	Traditional use	Usage	References
Qingteng Fengshi Jiu	T. hemsleyanum, Parabarium chunianum Tsiang, Zanthoxylum nitidum (Roxb.) DC.	Treatment of joint pain, wind cold dampness arthralgia	Oral administration, 15–25 mL once, 3 times a day	Ministerial standard
Qufengshi Yaojiu	T. hemsleyanum, Deeringia amaranthoides (Lam.) Merr, Blumea aromatica (Wall.) DC.	Treatment of arthralgia syndrome, rheumarthritis, rheumatoid arthritis, scapulohumeral periarthritis	Oral administration, 25 mL once, 3 times a day	Ministerial standard
Huatuo Fengtongbao capsule	T. hemsleyanum, Deeringia amaranthoides (Lam.) Merr, Zanthoxylum nitidum (Roxb.) DC, Panax notoginseng (Burk.) F.H. Chen	Treatment of arthralgia syndrome, rheumarthritis, rheumatoid arthritis, scapulohumeral periarthritis, joint pain, muscular constricture	Oral administration, 2 capsules once, 3 times a day	Ministerial standard
Sanyeqing Gypsum Decoction	T. hemsleyanum, Gypsum, Lonicera japonica Thunb, Houttuynia cordata Thunb, Ophiopogon japonicus (Linn. f.) Ker-Gawl	Treatment of infantile hyperpyretic convulsion	One dose a day, decoct twice in water, and take it 4–6 times after mixing	Xu (2006)
Sanyeqing Power	T. hemsleyanum	Treatment of blood avalanche, leucorrhea	Oral administration	Gao (2004)
Zhonggan mixture	T. hemsleyanum, Lysimachia christinae Hance, Imperata cylindrica, Citrus reticulata Blanco	Treatment of liver cancer	Oral administration, 30 mL once, 3 times a day	Jiang and Gong (2005)
Jinqi Tablet	T. hemsleyanum, ginsenoside, Astragalus propinquus Schischkin	Treatment of malignant tumor	Oral administration, 2 capsules once, 3 times a day	Wei et al. (2007)
Hua Shi Xuan Fei mixture	T. hemsleyanum, Nepeta cataria L, Lonicera japonica Thunb, Saposhnikovia divaricata (Trucz.) Schischk	Treatment of Covid-19	Oral administration, 125 mL once, 2 times a day	Zhejiang Provincial Drug Administration

Flavonoids and their glycosides

Modern phytochemical studies have indicated that flavonoids are the representative and predominated class of constituents isolated from T. hemsleyanum (Lin et al., 2016; Zhang et al., 2016) (Table 2). To date, fifty-one flavonoids and their glycosides have been extracted and identified from T. hemsleyanum. In this series compounds, quercetin (1), orientin (8), vitexin (13), isorhamnetin (20), apigenin (23) and kaempferol (36) are the main types of skeleton, some of their analogues can be identified from hydroxy moiety on C3′ and C4’ on the B ring of flavonoid aglycone. At present, many modern analytical techniques have been used for qualitative and quantitative analysis of flavonoids. Among them, ultra high performance liquid chromatography tandem triple quadrupole time of flight mass spectrometry (UPLC-ESI-Q-TOF-MS) has become a powerful tool for identifying the complicated compounds due to its higher mass accuracy and resolution. Our team used UPLC-ESI-Q-TOF-MS to identify 31 chemical constituents from the aerial part of T. hemsleyanum, including 22 flavonoids, such as isoorientin (10), quercetin (1), kaempferol (36), vitexin (13), isovitexin (17), kaempferol-3-glucoside (37), etc (Sun et al., 2018). According to the report (Liu et al., 2015), total flavonoids of T. hemsleyanum could protect the aged mice from acute lung injury through inhibiting the phosphorylation of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) in lung tissue. Moreover, the flavonoids of T. hemsleyanum had the activity of anti-lung cancer (Wei et al., 2018). Luteolin (30), a flavonoid found in T. hemsleyanum, acted as an anticancer agent against various types of human malignancies such as lung, breast, glioblastoma, prostate, colon, and pancreatic cancers (Muhammad et al., 2019). It is certain that T. hemsleyanum flavonoids give a new vision for researchers to explore clinical anticancer drugs.

Table 2

Chemical constituents isolated from the different parts of T. hemsleyanum.

Name	Detection Mode	Analysis parts of sample	Reference
Flavonoids and their glycosides
quercetin (1)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun (2018)
quercitrin (2)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Zeng et al. (2017)
quercetin-3-O-glucoside (3)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun (2018)
quercetin-3-O-rutinoside (4)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun et al. (2018)
quercetin-3-galactoside (5)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
quercetin-3-O-xylosylglucoside (6)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
quercetin-3-O-xylosylglucose-7-O-rhamnoside (7)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
orientin (8)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
orientin-2″-O-rhamnoside (9)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
Isoorientin (10)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018), Sun et al. (2018)
isoorientin-2″-O-rhamnoside (11)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
isoorientin −4″-O-xyloside (12)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
vitexin (13)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018), Sun et al. (2018)
vitexin-2″-O-rhamnoside (14)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018), Sun et al. (2018)
vitexin-2″-O-glucoside (15)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018), Sun et al. (2018)
vitexin-2″-O-arabinoside (16)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun et al. (2018)
isovitexin (17)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018), Sun et al. (2018)
isovitexin-2″-O-rhamnoside (18)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
isovitexin-2″-O-xyloside (19)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
isorhamnetin (20)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
isorhamnetin-3-rutinoside (21)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
isorhamnetin-3-pyranoarabinose-7-glucosylrhamnoside (22)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
apigenin (23)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun (2018)
apigenin-7-rhamnoside (24)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
apigenin-8-C-xylosyl-6-C-glucoside (25)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
apigenin-6-C-α-L-arabinose-8-C-β-D-glucose (26)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun et al. (2018)
eriodictyol (27)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
eriodictyol-O-hexoside I (28)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
eriodictyol-O-hexoside II (29)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
luteolin (30)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
luteolin-6, 8-di-C-hexoside (31)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
catechin (32)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018), Sun et al. (2018)
catechin glucopyranoside isomer (33)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
epicatechin (34)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018), Sun et al. (2018)
kaempferide (35)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
kaempferol (36)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018), Sun et al. (2018)
kaempferol-3-glucoside (37)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018), Sun et al. (2018)
kaempferol-3-rutinoside (38)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018), Sun et al. (2018)
kaempferol-3-sambubioside (39)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018), Sun et al. (2018)
kaempferol-3-O-neohesperidin (40)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Xu et al. (2014b)
kaempferol-3-O-rhamnoside (41)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Zeng et al. (2017)
kaempferol-7-O-rhamnose-3-O-glucoside (42)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Zeng et al. (2017)
kaempferol-3-robinoside-7-rhamnoside (43)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
kaempferol-3-rutinoside (44)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
kaempferol-3-O-carfuran-7-O-rhamnosyl glucoside (45)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
daidzein (46)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
biochanin A (47)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
procyanidin dimmer (48)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
procyanidin B1 (49)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Xu et al. (2014b)
procyanidin B2 (50)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Xu et al. (2014b)
procyanidin trimer (51)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Zeng et al. (2017)
Phenolic acids and derivatives
gallic acid (52)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun (2018), Xu et al. (2014b)
protocatechuic acid (53)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun (2018)
caffeic acid (54)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018), Sun et al. (2018)
dihydroxybenzoic acid hexoside (55)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
1-caffeoylquinic acid (56)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
3-caffeoylquinic acid (57)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
4-caffeoylquinic acid (58)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
5-caffeoylquinic acid (59)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
1-p-coumaroylquinic acid (60)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
4-p-coumaroylquinic acid (61)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
5-p-coumaroylquinic acid (62)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun (2018)
p-hydroxybenzaldehyde (63)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
p-coumaric acid (64)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
ferulic acid hexoside (65)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
salicylic acid (66)	UPLC-ESI-QTOF-MS/MS1H-NMR,13C-NMR, MS	aerial part, root tuber	Sun (2018), Fu et al. (2015)
chlorogenic acid (67)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018), Sun et al. (2018)
neochlorogenic acid (68)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Xu et al. (2014b), Fan et al. (2016)
cryptochlorogenic acid (69)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Xu et al. (2014b), Fan et al. (2016)
protocatechualdehyde (70)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
salicin-2-benzoate (71)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
trihydroxycinnamoylquinic acid isomer (72)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
protocatechuic acid hexoside (73)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
apiosylglucosyl 4-hydroxybenzoate (74)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
1-O-galloyl-β-D-glucose (75)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun et al. (2018)
protocatechol glucoside (76)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Zeng et al. (2017)
epigallocatechin (77)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun et al. (2018), Xu et al. (2014b)
vanillic acid-1-O-furan celery glucosyl ester (78)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
protocatechuic acid-1-O-furan celery glucosyl ester (79)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
methoxyphenol-1-O-furan glycosyl-O-glucoside (80)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
2-methoxy-4-methylbenzene-1-o-furacresyl glucoside (81)	UPLC-ESI-QTOF-MS/MS	root tuber	Zeng et al. (2017)
oxyresveratrol (82)	UPLC-ESI-QTOF-MS/MS	root tuber	Xu et al. (2014b)
dicaffeoylquinic acid (83)	UPLC-ESI-QTOF-MS/MS	root tuber	Xu et al. (2014b)
4-hydroxycinnamic acid (84)	1H-NMR, LC-MS	root tuber	Chen (2014)
Alkaloids
indole (85)	NMR, UV, MS	aerial parts	Fu et al. (2019)
indole-3-carboxylic acid (86)	NMR, UV, MS	aerial parts	Fu et al. (2019)
indole-3-propanoic acid (87)	NMR, UV, MS	aerial parts	Fu et al. (2019)
5-hydroxy-indole-3-carboxaldehyde (88)	NMR, UV, MS	aerial parts	Fu et al. (2019)
5-hydroxyindole-3-carboxylic acid (89)	NMR, UV, MS	aerial parts	Fu et al. (2019)
6-hydroxy-3, 4-dihydro-1-oxo-β-carboline (90)	NMR, UV, MS	aerial parts	Fu et al. (2019)
hippophamide (91)	NMR, UV, MS	aerial parts	Fu et al. (2019)
4-hydroxycinnamide (92)	NMR, UV, MS	aerial parts	Fu et al. (2019)
pyrrole-3-propanoic acid (93)	NMR, UV, MS	aerial parts	Fu et al. (2019)
S-(−)-trolline (94)	NMR, UV, MS	aerial parts	Fu et al. (2019)
Fatty acids
trihydroxy octadecadienoic acid (95)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
trihydroxy octadecenoic acid (96)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
dihydroxy octadecenoic acid (97)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
9-hydroxy-10,12-octadecadienoic acid (98)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
9-hydroxy octadecatrienoic acid (99)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
hydroxy-octadecenoic acid (100)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
hydroxy-octadecatrienoic acid (101)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
Dihydroxy-octadecatrienoic acid (102)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
dihydroartemisinin ethyl ether (103)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
Trihydroxy octadecadienoic acid isomer (104)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
hydroxy-oxo-octadecatrienoic acid (105)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
octadecenedioic acid di-Me-ester (106)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
stearic acid (107)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
linolenic acid (108)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
linoleic acid (109)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
palmitic acid (110)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
oleic acid (111)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
Organic acids and derivatives
malic acid (112)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
quinic acid (113)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
citric acid (114)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018), Sun et al. (2018)
azelaic acid (115)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
oxalic acid (116)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
galactonic acid (117)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
gallic acid (118)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
succinic acid (119)	UPLC-ESI-QTOF-MS/MS	aerial part, root tuber	Sun (2018), Sun et al. (2018)
fumaric acid (120)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
propanoic acid (121)	GC-MS	root tuber	Sun et al. (2018)
Terpenoids and steroids
β-sitosterol (122)	TCL	root tuber	Chen, 2014
daucosterol (123)	H-NMR, C-NMR, MS	root tuber	Ding et al. (2015)
campesterol (124)	GC-MS	root tuber	Sun et al. (2018)
Stigmasterol (125)	GC-MS	root tuber	Sun et al. (2018)
6-O-benzoyl daucosterol (126)	IR, H-NMR, EI-MS	root tuber	Guo (2018)
ergosterol (127)	IR, H-NMR, MS	aerial part	Ru et al. (2019)
taraxerone (128)	IR, H-NMR, MS	aerial part	Ru et al. (2019)
Taraxerol (129)	IR, H-NMR, MS	aerial part	Ru et al. (2019)
α-amyrine (130)	IR, EI-MS	aerial part	Ru et al. (2018)
pteroside Z (131)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
ganoderic acid H (132)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
3-epipapyriferic acid (133)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
oleanic acid (134)	H-NMR, C-NMR, MS	root tuber	Ding et al. (2015)
Saponins
Ginsenoside Rh1(135)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
Ginsenoside Rh2(136)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
Vinaginsenoside R1(137)	UPLC-ESI-QTOF-MS/MS	root tuber	Sun (2018)
Amino acid and derivatives
Phenylalanine (138)	UPLC-ESI-QTOF-MS/MS	root tuber, aerial part	Sun (2018)
pyroglutamic acid (139)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
glutimic acid hexose (140)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
Tryptophan (141)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun (2018)
L-glutamic acid (142)	UPLC-ESI-QTOF-MS/MS	aerial part	Sun et al. (2018)

Polysaccharide

Saccharide is another important active ingredient extracted from T. hemsleyanum (Shao et al., 2011). Polysaccharide has great potential in clinical application because of its unique pharmacological activity. However, due to the complex structure of polysaccharide, it is difficult and special to determine and synthesize their structures. Guo (2018) extracted the polysaccharides from roots of T. hemsleyanum, RTP-1, RTP-2 and RTP-3 were successively found by protein precipitation and purification. Moreover, further study indicated RTP-3-1 was high purity polysaccharide with a molecular weight of 1244.2 kDa, and it is mainly composed of 4 kinds of monosaccharides: arabinose, galacturonic acid, galactose, and fructose, the proportion is 8.39%, 7.18%, 20.70%, and 63.70%, respectively. Ru et al., 2018a, Ru et al., 2018b) extracted a polysaccharide THP from T. hemsleyanum, with the average molecular weight estimated as 93.307 kDa. The results of study on the composition of polysaccharide showed that it was mainly composed of rhamnose, arabinose, mannose, glucose, galactose with the molar ratio of 0.07:0.14:0.38:0.21:0.31. In 2019, Ru et al., 2019a, Ru et al., 2019b) successfully extracted polysaccharide THDP-3 from T. hemsleyanum with molecular weight of 77.98 kDa, which consists of rhamnose, arabinose, mannose, glucose and galactose with molar ratio of 1.0: 1.3: 2.5: 2.3: 3.1. Moreover, TDGP-3 mainly consists of →4)-α-D-GalAp-(1→, →4)-β-D-Galp-(1→ and →4)-α-D-Glcp-(1→, residues as backbones and β-D-Manp-(1→, →3,6-β-D-Manp-1→ and α-D-Araf-(1→residues as branches.

Phenolic acids

Phenolic acids refer to aromatic carboxylic acids with multiple phenolic groups substituted on one benzene ring. As a secondary metabolite, phenolic acids are widely found in many natural plants and have anti-inflammatory, antioxidant and lipid lowering effects. Twenty-three phenolic acids (No.52–84, Table 1) have been reported in the aerial parts of T. hemsleyanum, such as caffeic acid (54), chlorogenic acid (67), 1-O-galloyl-β-D-glucose (75), protocatechol glucoside (76), epigallocatechin (77), 1-caffeoylquinic acid (56), 3-caffeoylquinic acid (57), 4-caffeoylquinic acid (58), 5-caffeoylquinic acid (59), 1-p-coumaroylquinic acid (60), 4-p-coumaroylquinic acid (61) and 5-p-coumaroylquinic acid (62). There were twenty-one phenolic acids in the root tuber of T. hemsleyanum, some of which were the same as aerial parts.

Alkaloids

Alkaloids are a group of basic organic compounds containing nitrogen that exist in nature. Alkaloids are stored in small quantities in T. hemsleyanum, and the bioactivity investigations of those alkaloids are still rather rare. Wang (Fu et al., 2019) extracted the aerial parts of T. hemsleyanum with 90% ethanol, and then isolated ten alkaloids for the first time, including seven indole alkaloids, an amide, a maleimide, and a carboline. By comparing with the spectral data of known compounds, the alkaloids were respectively identified as indole (85), indole-3-carboxylic acid (86), indole-3-propanoic acid (87), 5-hydroxy-indole-3-carboxaldehyde (88), 5-hydroxyindole-3-carboxylic acid (89), 6-hydroxy-3, 4-dihydro-1-oxo-β-carboline (90), hippophamide (91), 4-hydroxycinnamide (92), pyrrole-3-propanoic acid (93) and S-(−)-trolline (94). The chemical structures were shown in Fig. 2 .

Fig. 2

Selected structures of chemical constituents isolated from T. hemsleyanum.

Organic acids and derivatives

The biologically essential organic acids have been isolated and characterized from T. hemsleyanum as well. Ten organic acids and seventeen fatty acids were identified from the aerial parts and root tuber of T. hemsleyanum, most of which were found in the aerial parts, except stearic acid (97), propanoic acid (121) and dihydroxy octadecenoic acid (102). All the organic acids and fatty acids are listed in No.112–121 and No.95–111 of Table 1, respectively.

Terpenoids and steroids

Terpenoids and steroids are other kinds of secondary metabolites of T. hemsleyanum, thirteen of these compounds have been isolated and identified (NO.122–134, Table 1). Liu (Yang et al., 1998; Liu et al., 2000) isolated and identified α-amyrine (130), β-sitosterol (122), ergosterol (127), taraxerone (128), taraxerol (129) from the aerial part of T. hemsleyanum. In addition, daucosterol (123), campesterol (124), stigmasterol (125), 6-O-benzoyl-daucosterol (126), pteroside Z (131), ganoderic acid H (132), 3-epipapyriferic acid (133) and oleanic acid (134) were successively separated from the tuber roots of T. hemsleyanum (Liu and Yang, 1999).

Inorganic elements

The mineral elements of TCM are indispensable supplements to the bioactive components, which are closely related to the efficacy, toxicity and side effects of TCM. Wu (Wu et al., 2018) demonstrated that T. hemsleyanum contained twenty-seven different mineral elements, namely Li, Be, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Ag, Cd, Cs, Ba, Hg, Ti, Pb, U. Moreover, Ca, Cu, Ni, Ba, Al, K have higher loading values, which are the characteristic elements of T. hemsleyanum. Wang (Wang et al., 2017) has indicated that the contents of Fe, Mn, Zn and Cu in three populations of T. hemsleyanum cultivated in different environments were 323.1–346.6, 36.3–38.1, 23.0–25.1, 3.8–4.1 mg kg−1, respectively.

Other compounds

In addition to the seven kinds of compounds mentioned above, amino acids derivatives in T. hemsleyanum are also reported, such as phenylalanine, pyroglutamic acid, glutimic acid hexose, tryptophan, L-glutamic acid.

Pharmacology

The ethnomedical uses of T. hemsleyanum have stimulated various pharmacological studies on it. The extracts and isolated compounds from T. hemsleyanum showed a variety of bioactivities, such as antiviral, antibacterial anti-oxidant, antipyretic, analgesic, hepatoprotective, immunoregulatory, and antitumor activity. The detailed pharmacological activities of T. hemsleyanum were presented in Table 3 and summarized as follows.

Table 3

Pharmacological effects of T. hemsleyanum.

Crude drug/compounds	Model method	Dose range/concentration	Results	references
Antiviral Activity
A, F, S1, S2	Mice and CEF infected with HVJ, influenza virus PR6, VSV	0.1–25 g/kg (i.g. for 114 days) in vivo, 0.125–1 mg/mL in vitro	Cell proliferation↓, plaque formation↓, animal mortality↓	Yang et al. (1989)
quercetin (1), quercitrin (2), epicatechin (34), quercetin-3-O-rutinoside (4), kaempferol (36), kaempferol-3-glucoside (37), kaempferol-3-rutinoside (38), procyanidin dimmer (48)	MDCK cells inoculated with influenza virus PR8-NS1-Gluc	12.5–100 μg/mL	IC50: 27.4 μg/mL, no cytotoxicity was observed at a concentration of as high as 200 μg/mL	Ding et al. (2019)
Ethyl acetate extracts of T. hemsleyanum	HepG2 cells		IC50: 1.3–48.6 mg/L, CC50: 385.0 ± 56.9 mg/L	Yang and Wu (2009)
BAF, EAF	MA104 cells	TC50 and EC50 of BAF: 2−3 and 2−10, respectively, TC50 and EC50 of EAF: 2−5 and 2−11, respectively	TI value of BAF: 128, TI value of EAF: 64	Yang, Gao and Yan (2019)
PEF	HIV-1ⅢB cells	CC50: 92.54 μg/mL	EC50: 3.54–78.56 μg/mL, TI: 2.03–43.18	Dong and Li (2016)
Antibacterial Activity
EAF, CFF	E. coli, S. typhi, K. pneumonia, P. citrinum, A. flavus, A. niger, R. nigricans	MIC of EAF: 125–250 μg/mL, MIC of CFF: 31.3–125 μg/mL	Inhibitory diameter zone >10 mm	Xiong (2015)
T. hemsleyanum ‘s polysaccharide	E. coli		Inhibiting E. coli's growth through suppressing the F6P's secondary phosphorylation	Chen et al. (2019)
Antioxidant Activity
Total phenolic acid of T. hemsleyanum	DPPH assay, ABTS Assay, FRAP Assay	8.28–38.47 mg/g	DPPH, 3.32 mmol of Trolox/g DW; ABTS, 1.38 mmol of Trolox/g DW; FRAP, 1.85 mmol of FeSO4/g DW	Sun et al. (2013)
Quercetin (1), quercetin-3-O-glucoside (3), procyanidin B1 (49), procyanidin B2 (50), protocatechualdehyde (70), epigallocatechin (77)	DPPH assay	IC50: 12.4–15.99 μmol/L	Their antioxidant activities were better than that of vitamin C	Fu et al. (2015)
Methanol extracts of T. hemsleyanum leaf	SD rats intraperitoneally injected with D-galactose solution	200–1000 mg/kg	SOD↑, GSH↑, MDA↓, T-AOC↑	Sun et al. (2017)
A polysaccharide TDGP-3 from T. hemsleyanum	ICR mice received a high-fat diet for 35 consecutive days	100–300 mg/kg	SOD↑, GSH-Px↑, CAT, MDA↓	Chu et al. (2019)
Ethanol extract of T. hemsleyanum	DPPH assay, FRAP Assay, Prieto method	20–1000 μg/mL	The antioxidant capacity was associated with the contents of total flavonoids and total phenolics	Xu et al. (2015)
Total flavonoids of T. hemsleyanum root tuber	DPPH assay, ABTS Assay, FRAP Assay		DPPH, 27.4 μmol of Trolox/g DW; ABTS, 35.1 μmol of Trolox/g DW; FRAP, 43.3 μmol of Trolox/g DW	Ye and Liu (2015)
Total flavonoids and phenolic acid of T. hemsleyanum leaf	DPPH assay	6.25–100 mg/kg	The antioxidant capacity was associated with the contents of total phenolics	Hossain et al. (2011)
Antipyretic and Analgesic Activity
Ethanol extract of T. hemsleyanum	Rats induced with Brewer's yeast or 2, 4-dinitrophenol	1.2–4.8 g/kg	Body temperature↓, and the duration was up to 180 min	Huang et al. (2005)
Aqueous extract of T. hemsleyanum	Wiser rats induced with Brewer's yeast	2–6 g/kg	5-HT↓, NE↓, DA↓	Yang and Wang (2014)
A polysaccharide from T. hemsleyanum aerial part	Kunming mice induced with Brewer's yeast	200, 400 mg/kg	Body temperature↓	Zhu et al. (2020)
Ethanol extract of T. hemsleyanum	Mice induced with acetic acid and hot plate test	1.2–4.8 g/kg	The pain threshold↑, times of twisting body↓	Huang et al. (2005)
Ethanol extract of T. hemsleyanum	Mice induced with acetic acid	2.5 g/kg	Times of twisting body↓, the pain threshold↑	Wang (2017)
Aqueous extract of T. hemsleyanum	Mice induced with diethylstilbestrol and oxytocin	1.25–5.0 g/kg	Times of twisting body↓, the pain threshold↑, the tension of smooth muscle↓	Lv et al. (2011)
Ethanol extract of T. hemsleyanum	Kunming mice induced with acetic acid and hot plate test	30–120 mg/kg	The pain threshold↑, times of twisting body↓, the maximum of analgesic ratio was 65.58%	Liao et al. (2017)
Anti-inflammatory Activity
Ethanol extract of T. hemsleyanum	Xylene-induced ear edema in mice	2.5 g/kg	Degree of swelling↓, the inhibition rates↑		Wang (2017)
Ethanol extract of T. hemsleyanum	Xylene-induced ear edema in mice, carrageenan-induced paw edema of acute inflammation in rats	30–120 mg/kg (i.g. for 3 days or 7 days)	The inhibition rates↑		Liao et al. (2017)
Ethanol extract of T. hemsleyanum	Xylene-induced ear edema in mice, albumin-induced paw edema in rats	1.2–4.8 g/kg (i.g. for 4 days)	Degree of swelling↓, the inhibition rates↑		Huang et al. (2005)
A purified polysaccharide from T. hemsleyanum	RAW264.7 cells induced by LPS	12.5–50 μg/mL	COX-2↓, iNOS↓		Chu et al. (2019)
Total flavonoids of T. hemsleyanum	C57BL/6 J mice induced by LPS	40–80 μg/g (i.g. for 3 days)	TNF-α↓, IL-1β↓, IL-6↓, IL-12p40↓, sTNF-R1↓, IL-10↑		Liu et al. (2015)
Total flavonoids of T. hemsleyanum	RAW264.7 cells induced by LPS	10–160 μg/mL	TNF-α↓, IL-1β↓, IL-6↓, IL-12p40↓, sTNF-R1↓, IL-10↑, iNOS↓, NF-κB↓, phosphorylation of JNK↓		Liu et al. (2016)
Aqueous extract of T. hemsleyanum	COPD model rats were induced by exposure to cigarette smoke and endotracheal instillation of LPS	1.0 g/kg (i.g. for 28 days)	IL-23↓, IL-17↓		Wang (2016)
Polysaccharide from T. hemsleyanum	RAW264.7 cells induced by LPS	25–100 μg/mL	TNF-α↓, IL-6↓		Huang (2017)
Total flavonoids of T. hemsleyanum	Balb/c mice induced by Con A	1–4 g/kg (i.g. for 28 days)	IL-17↓, IL-6↓, TGF-β1↑, IL-10↑, Foxp3↑, RORγt↓,		Ji et al. (2019)
Hepatoprotective Activity
Aqueous extract of T. hemsleyanum	SD rats induced by CCl4	1.6 g/kg, 16 g/kg (i.g. for 6 days)	GOT↓, ALP↓, MDA↓, SOD↑, GPT↓		Wu et al. (2006)
Aqueous extract of T. hemsleyanum	Kunming mice induced by CCl4	0.6–2.4 g/kg (i.g. for 7 days)	ALT↓, AST↓, MDA↓, SOD↑		Zhong et al. (2006)
Total amino acids from T. hemsleyanum	Kunming mice induced by CCl4	250, 500 mg/kg (i.g. for 7 days)	ALT↓, AST↓, liver index↓, MDA↓, SOD↑		Huang and Mao (2007)
Ethanol extract of T. hemsleyanum	Kunming mice induced by α-isothiocyanate	1.0–4.0 g/kg (i.g. for 10 days)	ALT↓, AST↓, MDA↓, SOD↑, TNF-α↓,		Li et al. (2018)
Aqueous extract of T. hemsleyanum	SD rats induced by CCl4	1.0–4.0 g/kg (i.g. for 8 weeks)	ALT↓, AST↓, HA↓, LN↓, T-BiLi↓, TP↓		Zhang and Ni (2008)
Aqueous extract of T. hemsleyanum	Kunming mice induced by calmette-Guerin bacillus vaccine and LPS	20–40 g/kg (i.g. for 10 days)	MDA↓, SOD↑, ALT↓, AST↓, LDH↓		Yang (2008)
Polysaccharide from T. hemsleyanum	ICR mice induced by CCl4	0.125, 0.2 mg/g (i.g. for 7 days)	ALT↓, AST↓, MDA↓, SOD↑		Ma et al. (2012)
Immunoregulatory Activity
Ethyl acetate extract of T. hemsleyanum	ICR mice induced by Con A	2.5–25 g/kg (i.g. for 15 days)	IFN-γ↑, TNF-α↑		Ding et al. (2008)
Aqueous extract of T. hemsleyanum	Back of SD rats were immersed in 100 °C water for 12s	1.2–4.8 g/kg (i.g. for 7 days)	IgA↑, S-IgA↑, MDA↓, IL-6↓		Zhong et al. (2006)
T. hemsleyanum power	Sanhuang Broiler mixed feeding with 0.5%, 1% and 2% of T. hemsleyanum power diet for 20 days		IL-1↑, IL-4↑, the index of immune organs↑, TNF-γ↑, TNF-α↑		Chen and Li (2015)
Ethyl acetate extract of T. hemsleyanum	ICR mice induced by Con A	9.1–91.2 mg/kg (i.g. for 15 or 30 days)	IFN-γ↑, TNF-α↑, the proliferation of T and B↑,		Xu et al. (2008)

Antiviral activity

According to Yang's literatures (Yang et al., 1989), the nitrogenous alkali-containing extract (A), ketone-containing extract (F), crude extract (S1), and crude extract (S2) of T. hemsleyanum had different antiviral effect on mice and chicken embryo fibroblast (CEF) infected with Hemagglutinating virus of Japan (HVJ), influenza virus PR6, vesicular stomatitis virus (VSV). Specifically, S2 strongly inhibited the proliferation of influenza virus PR6 with at the concentration of 0.5 mg/mL, and 0.5 mg/mL S1 has obvious antiviral effect on HVJ. At the concentrations of 10 mg/mL and 1 mg/mL, both F and S1 displayed a strong suppressive effect on the plaque formation of VSV. In vivo, A, F, S1, S2 have different degrees of antiviral activity. When the concentration of A was 0.1 g/kg, the protective rate was up to 50%, and that of S1 (0.2 g/kg) was 20%. However, the author did not give the sample preparation method. Ding et al. (2019) had demonstrated compounds quercetin-3-O-rutinoside (4), kaempferol (36), kaempferol-3-glucoside (37), quercitrin (2), quercetin (1), kaempferol-3-O-rutinoside (38), procyanidin dimmer (48), and epicatechin (34), which were isolated from T. hemsleyanum, were positively related to the activity of T. hemsleyanum against H1N1 influenza virus. The ethyl acetate extracts of T. hemsleyanum have been shown to obviously restrain the secretion of HbsAg and HbeAg released by HBV, with the IC50 values of 1.3–48.6 mg/L. However, the specific mechanism of action needs to be further confirmed (Yang and Wu, 2009). Wang had proved that the n-butanol and ethyl acetate extraction of T. hemsleyanum had antiviral activity against RSV and were superior to ribavirin with the EC50 values of 0.008 mg/L (Wang et al., 2019). Moreover, the T. hemsleyanum extracts had different degrees of inhibition to different HIV-1 strains. The EC50 values were between 3.54 μg/mL and 78.56 μg/mL and the therapeutic index values were between 2.03 and 43.18. The EC50 values of T. hemsleyanum extract for blocking the fusion of HIV-1 chronic infected cells and normal lymphocytes C8166 cells was 14.79 μg/mL and the EC50 for inhibiting the recombinant HIV-1 reverse transcriptase was 170.15 μg/mL (Dong and Li, 2016). Although these studies have demonstrated that T. hemsleyanum could be used in the treatment of different viruses, the mechanism has been barely reported.

Antibacterial activity

T. hemsleyanum was used in the treatment of throat swelling and pain, sore and toxin, pneumonia and fever, and these diseases were mostly relevant to the invasion of microorganisms. Xiong (2015) used S. aureus LMA1213 and B. subtilis LMA0106, E. coli LMA 1226, S. typhi LMA0217, K. pneumonia LMA0725, M. racemosus LMA3221, P. citrinum LMA7126, A. flavus LMA0816, A. niger LMA3601, R. nigricans LMA2429 as tested species, and evaluated the inhibitory diameter, minimum inhibitory concentration (MIC) of T. hemsleyanum ethanol extracts using oxford cup method and broth micro-dilution method. The results indicated that T. hemsleyanum showed the strongest activity against S. aureus and B. cereus, MIC value both were 62.5 μg/mL. Ethyl acetate extract of T. hemsleyanum ethanol extract (EAF) exhibited the strongest inhibitory activity on E. coli, S. typhi and K. pneumonia. MIC value ranges from 125 μg/mL to 250 μg/mL. Meanwhile, chloroform extract of T. hemsleyanum ethanol extract (CFF) exhibited remarkable activity against P. citrinum, A. flavus, A. niger and R. nigricans. MIC value ranges from 31.3 μg/mL to 125 μg/mL. Chen (Chen et al., 2019) had clarified the antibacterial mechanism of T. hemsleyanum's polysaccharide was that it could inhibit the proliferation of E. coli by interfering with glycolysis and gluconeogenesis.

Antioxidant activity

Antioxidant activity is a prominent value for the further development of natural products. According to the study (Sun et al., 2013), 80% methanol extract of T. hemsleyanum leaves exhibited the highest DPPH radical scavenging activity, with the value of 3.32 mmol of Trolox/g DW, and a similar result was also found in the ABTS radical scavenging activity experiment (1.38 mmol of Trolox/g DW). In the ferric reducing activity assay, 80% methanol extract of T. hemsleyanum leaves had the highest value (1.85 mmol of FeSO4/g DW). Moreover, the results of relationship between phenolic content and antioxidant activity suggested that the phenolics of T. hemsleyanum leaves extracts were the main contributors to the antioxidant activities. In Fu's research (Fu et al., 2015), it had been found that the antioxidant activities of quercetin (1), epigallocatechin (77), procyanidin B1 (49), procyanidin B2 (50), protocatechualdehyde (70) and quercetin-3-O-glucoside (3) in T. hemsleyanum were better than those of vitamin C, and the antioxidant capacity was correlated with the amount of total flavonoids and total polyphenols. It was also confirmed by literature (Xu et al., 2015; Ye and Liu, 2015), which suggested that total flavonoids and total phenols might be the material basis of antioxidant activity. Sun (Sun et al., 2017) established an oxidative stress rat model by D-galactose, total antioxidant capacity, superoxide dismutase (SOD), glutathione (GSH) peroxidase activities of rats were increased after treatment of T. hemsleyanum. Meanwhile, the content of GSH was increased and malondialdehyde (MDA) content was decreased in plasma and tissues of these rats. Interestingly, Chu (Chu et al., 2019a, Chu et al., 2020) isolated a purified polysaccharide from T. hemsleyanum, the results of pharmacological experiment showed that it could ameliorate oxidative damage in RAW264.7 cells via Nrf2-Keap1 and Sirt1-FoxO1 pathways. Based on the above findings, the antioxidant activity of T. hemsleyanum has the characteristics of multi-components, multi-targets and multi-pathways.

Antipyretic and analgesic activity

In the folk, T. hemsleyanum is widely used in the treatment of infantile hyperpyretic convulsion, which was also confirmed by Brewer's yeast or 2, 4-dinitrophenol induced hyperthermia test of rats (Huang et al., 2005). More specifically, the temperature of rats treated with T. hemsleyanum extracts remarkably fell and 5-hydroxytryptamine (5-HT), norepinephrine (NE), dopamine (DA) in hypothalamus also significantly decreased (Yang and Wang, 2014). Besides, a purified polysaccharide from aerial parts of T. hemsleyanum with average molecular weight of 66.2 kDa could markedly suppress the levels of prostaglandin E2 (PGE2) in serum of mice (Zhu et al., 2020). The analgesic activity of T. hemsleyanum was investigated by acetic acid or oxytocin induced writhing response in mice and hot plate test, and the results manifested that T. hemsleyanum could reduce the number of abdominal writhing and increase the pain threshold in hot plate test in a dose-dependent manner (Wang, 2017). T. hemsleyanum could reduce the tension of isolated mouse uterus and the writhing times of oxytocin-induced mice model (Lv et al., 2011). The results further showed the aerial parts of T. hemsleyanum also had analgesic activity taken these finding into consideration as follow: increased the rate of pain threshold prolongation with the maximum extension of analgesic ratio of 65.58%, inhibited acetic acid-induced writhing pain in mice, prolonged the latency of mice's writhing and alleviated the writhing responses with the maximum inhibition ratio of 51.80% (Liao et al., 2017). However, the bioactive compounds and the mechanism of action have not been reported in any literature.

Anti-inflammatory activity

Inflammation has been reported to produce negative effect on various diseases. Consistent with traditional uses, T. hemsleyanum exerted anti-inflammatory activity, the regulation mechanism was closely related to the target molecules including NF-κB and MAPK (Liu et al., 2015). A purified polysaccharide with the average molecular weights of 478.33 kDa from T. hemsleyanum could attenuate inflammation stimulated with lipopolysaccharide (LPS) through suppressing the phosphorylation of MAPKs, down-regulating the expression of COX-2 and iNOS in RAW264.7 cells. Moreover, the purified polysaccharide also improved the growing development and athletic ability of Caenorhabditis elegans (C.elegans), ameliorated the ability of scavenge ROS, O2 −, recovered GSH against LPS-induced inflammation in C. elegans (Chu et al., 2019a, Chu et al., 2020). Liu (Liu et al., 2016) discovered that T. hemsleyanum reduced the production of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin 6 (IL-6), interleukin 12 subunit p40 (IL-12p40), soluble TNF receptors 1 (sTNF-R1) and increased anti-inflammatory cytokine interleukin 10 (IL-10) expression in LPS-induced RAW264.7 cells, which were consistent with the other studies (Wang, 2016; Huang, 2017). Meanwhile, T. hemsleyanum dose-dependently inhibited the production of inducible NO synthase (iNOS) and NO, attenuated the up-regulated expression of Toll-like receptor 4 (TLR4), myeloid differentiation factor-2 (MD-2), myeloid differentiation protein 88 (MyD88) and TLR4/MD-2 complex induced by LPS. Along with the change of TLR4/MD-2, the phosphorylation and activity of c-Jun N-terminal kinase (JNK) and NF-κB were changed at the same time. These data revealed T. hemsleyanum might contribute to the alleviation of LPS-induced inflammatory reaction in RAW264.7 cells via TLR4/MD-2 mediated NF-κB and JNK pathway. Besides, our previous research proved that total flavonoids from T. hemsleyanum (1, 2 and 4 g/kg) and a positive control drug bifendate (200 mg/kg) could ameliorate inflammatory response in autoimmune hepatitis mice by mediating Treg/Th17 immune homeostasis (Ji et al., 2019).

Hepatoprotective activity

Previous findings have demonstrated that T. hemsleyanum has protective effects on various types of liver injury. Water decoction of T. hemsleyanum (1.6 g/mL and 0.16 g/mL) relieved liver injury caused by carbon tetrachloride (CCl4) through decreasing the contents of glutamic-pyruvic transaminase (GPT), glutamic-oxalacetic transaminase (GOT), alkaline phosphatase (ALP) and MDA, while increasing the activity of SOD (Wu et al., 2006). Moreover, water extract and total amino acids of T. hemsleyanum could obviously reduce the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), liver index and the content of MDA in liver, increase the activity of SOD in live, and the protective effect of T. hemsleyanum on liver injury was better than that of biphenyl diester. Furthermore, the pathologic changes of hepatic tissue demonstrated that they could reduce the degree of necrosis, degeneration of inflammatory cell, and infiltration of hepatocytes (Zhong et al., 2006a, Zhong et al., 2006b; Huang and Mao, 2007). Besides, T. hemsleyanum extract had a protective effect on liver injury induced by α-isothiocyanate in mice, which was relevant to the reduction of inflammatory factors, promotion of the total bilirubin metabolism and alleviation of the lipid peroxidation (Li et al., 2018). As for chronic liver injury, Zhang (Zhang and Ni, 2008) observed that the extract of T. hemsleyanum reduced the levels of ALT, AST, hyaluronan (HA), laminin (LN), and total bilirubin (T-BiLi), suppressed the content of total protein (TP) and albumin, improved the ratio of albumin/globulin and the survival rate of chronic hepatic damage rat administrated with CCl4 (Fig. 3 ). With regard to the mice with immune liver injury induced by Calmette-Guerin bacillus vaccine and LPS, T. hemsleyanum (20, 30, 40 g/kg) could also regulate the change of above factors at different levels (Yang, 2008). Unfortunately, the bioactive components of T. hemsleyanum against liver injury have not been reported so far.

Fig. 3

The protective effects of T. hemsleyanum on liver injury.

Immunoregulatory activity

It is believed that the ability of body to cope with diseases depends not only on the adaptive immune response of T and B lymphocytes to specific antigens, but also on the natural immune response. Once the immune system is out of order, the pathological changes of organ tissues will ensue. Xu (Xu et al., 2008) had reported that the ethyl-acetate fraction of T. hemsleyanum enhanced the proliferation of T and B lymphocyte and antibody activity at the dose of 1.82 mg/mL, 5.48 mg/mL, and 9.12 mg/mL, affected delayed-type hypersensitivity and mononuclear-macrophage phagocytosis, and increased the production of serum interferon-gamma (IFN-γ) and serum TNF-α at the dose of 9.12 mg/mL, which was in accordance with Ding's findings (Ding et al., 2008). The extract of T. hemsleyanum (1.2, 2.4, 4.8 g/kg) could antagonize the decrease of serum immunoglobulin A (IgA) content and secretory immunoglobulin A (S-IgA) content in ileum mucus, spleen lymphocyte proliferation, natural killer cell activity, the increase of MDA content in intestinal mucus and serum IL-6 level in scalded rats (Zhong et al., 2006a, Zhong et al., 2006b). In addition, it has been reported that T. hemsleyanum could also increase the levels of IL-1, IL-4 and the index of immune organs (Fig. 4 ) (Chen and Li, 2015). Due to the complex constituents of the extract, the immunomodulatory mechanism of T. hemsleyanum need to be further studied.

Fig. 4

T. hemsleyanum enhanced the differentiation of T cell, reduced inflammatory response, improved cell immunity and alleviated cell damage.

Antitumor activity

In recent years, T. hemsleyanum has been widely used in the prevention and treatment of lung cancer, stomach cancer, colorectal cancer, liver cancer, breast cancer, cervical cancer, thyroid cancer, esophageal cancer, pancreatic cancer, lymphoid cancer and brain tumor (Chu et al., 2019, 2020). It has the characteristics of multi-target, multi-pathway, synergistic effect, non-toxicity, which is valuable for the development of new drugs for the treatment of tumor. Although the mechanism has not been fully elucidated, its antitumor effect may be achieved by inhibiting tumor cell proliferation and migration, inducing cell apoptosis, enhancing immune function.

Inhibiting tumor cell proliferation and migration

The abnormal regulation of cell cycle is an important reason for tumorigenesis. CyclinD1 is a key regulatory protein in G1 phase, and the disorder of G1 phase would lead to the occurrence of tumor. Proto oncogene c-myc is a nuclear protein regulatory gene, Lgr5 is a stem cell marker, and both of them highly expressed in a variety of tumor. Epithelial-mesenchymal transition (EMT) is characterized by a loss of epithelial proteins including E-cadherin, and increased expression of vimentin. EMT is closely connected with the migration and invasion of malignant tumors which accompanied by change activity of matrix metalloproteinase (MMPs) and tissue inhibitor of matrix-metallo proteinase (TIMPs). According to the studies (Xia et al., 2018; Zhang et al., 2017a, Zhang et al., 2017b; Ni et al., 2009; Zhong and Wei, 2014; Zhong et al., 2016; Zhong et al., 2017; Yu et al., 2016; Yu, 2016; Wang et al., 2017; Wang et al., 2014; Jiang and Xu, 2015; Xu et al., 2011; Xu et al., 2010; Yan et al., 2013a, Yan et al., 2013b; Yan et al., 2013a, Yan et al., 2013b), the active components of T. hemsleyanum on the one hand could suppress the expression of Lgr5, CyclinD1 and c-myc, block the cell cycle in G0/G1 phase, reduce the transformation of tumor cells from G1 phase to S phase and then intercept the cell cycle in S and G2/M phase, so that the mitosis process of tumor cells would be blocked and cell proliferation be inhibited (Fig. 5 ). On the other hand, they could decrease the expression of E-cadherin, vimentin, MMP-2 and MMP-9, increase the expression of TIMP-2, suppress the activity of the Wnt/β-catenin pathway and Notch pathway, so that tumor migration and invasion would be inhibited.

Fig. 5

T. hemsleyanum blocked the mitosis process of tumor cells and inhibited the cell proliferation, invasion and metastasis.

Inducing apoptosis of tumor cells

Apoptosis is a cell suicide phenomenon that occurs in a specific time and space. It is closely regulated through a variety of cell signaling pathways, such as mitochondrial apoptotic pathway and death receptor apoptotic pathway. Bcl-2 protease family is the key protein in mitochondrial apoptosis pathway, which can be divided into two categories: pro apoptotic proteins such as Bax and bid and anti-apoptotic proteins such as bcl-2 (Fig. 6 ). Cytochrome c (Cyt-c) and apoptosis inducing factor were released under the action of apoptotic signal. The combination of Cyt-c and apoptosis activator, such as caspase-8, caspase-9 and caspase-10 could activate the downstream apoptosis executor enzymes, such as caspase-3 and caspase-6, and that finally lead apoptosis. Besides, ROS can produce many kinds of free radicals, which cause cell stress reaction and trigger cell apoptosis. However, many types of antioxidant enzymes can scavenge excessive ROS, such as SOD, catalase (CAT) and glutathione peroxidase (GSH-Px). As shown in Table 4 , T. hemsleyanum could reduce mitochondrial membrane potential, increase intracellular Ca2+ concentration, down-regulate the expression of Bcl-2 protein, promote the expression of Bax and Cyt-C protein in tumor cells, and thus activate mitochondrial apoptosis induction pathway. On the other hand, it could activate the expression of caspase protease family, thus induce apoptosis (Peng et al., 2016a, Peng et al., 2016b; Sun et al., 2018; Chen et al., 2018; Xiong et al., 2015; Peng, 2016; Liu and Xia, 2010; Li and Wei, 2012; Ding et al., 2017; Lin et al., 2016; Li and Peng, 2014; Wang and Peng, 2015; Zeng et al., 2012; Zeng et al., 2013; Zhong et al., 2014; Zhang et al., 2017a, Zhang et al., 2017b; Zhang et al., 2010; Wu et al., 2016). Furthermore, T. hemsleyanum could reduce the activity of SOD, CAT and GSH-Px, increase the level of MDA, and enhance the oxidative stress response of tumor cells, thus accelerate the occurrence of apoptosis (Xiong, 2015).

Fig. 6

The enhancement of mitochondrial membrane permeability, the destruction of mitochondrial integrity and the stimulation of ROS cause apoptosis of tumor cells.

Table 4

Mechanism of T. hemsleyanum in the treatment of tumor.

Crude drug/Compound	Methods used	Dose range/concentration	Results	Reference
Inhibiting proliferation of tumor cell
quercetin-3-O-glucoside (3)	NBT-II cells	1–25 μg/mL	HGF/SF-Met signaling↓, migration↓, invasion↓	Xia et al. (2018)
T. hemsleyanum Flavones	EC9706 cells	0.5–20 g/L	The inhibition rate of cell↑, adhesion rate↓, migration rate↓, invasion cell number↓, Notch1 mRNA ↓	Zhang et al. (2017)
T. hemsleyanum Flavones	mice inoculated H22 cells	15–90 mg/kg (i.g. for 12 days)	Cell growth↓, TIMP-2↑	Ni et al. (2009)
T. hemsleyanum Flavones	A549 cells	0.5–10 g/L	Cell growth↓, apoptosis↑, p-p38↑, p-ERK↑	Zhong et al. (2014)
T. hemsleyanum Flavones	A549 cells	0.5–10 g/L	Cell proliferation↓, cell migration↓, MMP-2↓, MMP-9↓, TIMP-2↑	Zhong et al. (2016)
T. hemsleyanum Flavones	A549 cells	1–10 mg/mL	Cell proliferation↓, DUB activity↓, ub-prs↑, USP14↓, UCHL5↓, POH1↓	Zhong et al. (2017)
T. hemsleyanum Flavones	HT29 and SW620 cells	1.6–6.4 mg/mL	The proportion of S + G2/M phase, β-Catenin↓, Cyclin D1↓, c-myc↓	Yu et al. (2016)
T. hemsleyanum Flavones	AOM-DSS induced C57BL/6 mice	4–8 g/kg (i.g. for 114 days)	Tumor volume↓, Lgr5↓, Cyclin D1↓, c-myc↓, E-cadherin↓, Vimentin↓, Wnt/β-catenin pathway↓	Yu (2016)
T. hemsleyanum Flavones	BALB/c mice inoculated HepG2 cells	3.75–15 g/kg (i.g. for 21 days)	Tumor growth↓	Wang et al. (2017)
Ethylacetate extract of T. hemsleyanum	HepG2 cells	5–25 g/kg (i.g. for 21 days)	Tumor growth↓, IFN-γ↑, TNF-α↑	Wang et al. (2014)
Ethanol extract of T. hemsleyanum	MCF-7 cells	5–160 g/L	Cell proliferation↓, migration↓, proportion of cells in G0/G1 phase↓, apoptosis rate↑	Jiang et al. (2015)
Ethanol extract of T. hemsleyanum	HL60 cells	1.56–6.25 μg/mL	Cell proliferation↓, apoptosis rate↑	Xu et al. (2011)
Ethanol extract of T. hemsleyanum	K562 cells	3.13–100 μg/mL	Cell growth↓, apoptosis rate↑, P53↑, C-myc↓	Xu et al. (2010)
Lyophilized powder of T. hemsleyanum	C57BL/6 J mice inoculated H22 cells	1.79–7.16 g/kg	Cell growth↓, prolong survival rate↑	Yan et al. (2013)
Lyophilized powder of T. hemsleyanum	BALB/c mice inoculated A549 cells	1.79–7.16 g/kg	Cell growth↓, tumor volume↓	Yan et al. (2013)
Inducing apoptosis of tumor cells
Ethylacetate extract of T. hemsleyanum	HepG2 cells	0–200 μg/mL	Ca2+↑, cytochrome c↑, caspase-3↑, caspase-9↑	Peng et al. (2016)
Methanol extract of T. hemsleyanum leaves	Kun-Ming mice inoculated H22 cells	250–500 mg/kg (i.g. for 16 days)	Cell growth↓, Bcl-2↓, Bax↑, VEGF↓, cle-caspase 9↑, cle-caspase 9↑	Sun et al. (2018)
Ethylacetate extract of T. hemsleyanum	HepG2 and SMMC-7721 cells	50–250 μg/mL	Cell proliferation↓, Bcl-2↓, caspase-3↑, Bax ↑	Chen et al. (2018)
Ethanol extract of T. hemsleyanum root tuber	HeLa cells	10–40 μg/mL	Cell growth↓, caspase-3↑, caspase-9↑, caspase-8↑	Xiong et al. (2015)
Ethylacetate extract of T. hemsleyanum	HepG2 cells	50–200 μg/mL	The proportion of Bcl2/Bax↓, p53↑, outflow of Ca2+↓, Cytochrome C↑, caspase-9↑, PARP↑, pro-caspase-3↑	Peng (2016)
Ethylacetate extract of T. hemsleyanum	HT-29 cells	0.1–10 mg/L	Cyto C↑, Bax↓, Cytochrome C↑	Liu and Xia (2010)
Ethylacetate extract of T. hemsleyanum	C57BL/6 J mice inoculated Lewis lung cancer cells	0.1–0.3 g/kg (i.g. for 14 days)	Apoptosis rate↑, Bcl2↓, Bax↑, caspase-3↑	Li and Wei (2012)
Ethylacetate extract of T. hemsleyanum	PANC-1 cells	50–200 μg/mL	Bax↑, P53↑, Bcl2↓	Ding et al. (2017)
Ethylacetate extract of T. hemsleyanum	Balb/c mice inoculated HT29 cells	0.1–0.3 g/kg (i.g. for 14 days)	Tumor weight↓, caspase-3↑	Lin et al. (2016)
Ethanol extract of T. hemsleyanum	Hela cells	1–16 mg/L	The inhibition rate of cell↑	Li and Peng (2014)
Ethylacetate extract of T. hemsleyanum	HCCC-9810 cells	25–200 μg/mL	Cell proliferation↓, caspase-3↑	Wang and Peng (2014)
Ethanol extract of T. hemsleyanum	A549 cells	1–100 mg/L	Rate of apoptosis↑	Zeng et al. (2012)
Ethanol extract of T. hemsleyanum	A549 cells	1–100 mg/L	Caspase-3↑	Zeng et al. (2013)
Ethylacetate extract of T. hemsleyanum	H1299 cells	0.5–10 mg/mL	pro-caspase-3↓, cle-PARP↑, pro-caspase-9↓, PARP↓, cle-caspase-3↑, cle-caspase-9↑	Zhong et al. (2014)
T. hemsleyanum Flavones	SPC-A-1 cells	0.5–10 g/L	Cell proliferation↓, cleaved- caspase-3↑	Zhang et al. (2017)
T. hemsleyanum Flavones	SMMC-7721 cells	2–10 mg/mL	Cell proliferation↓, Rate of apoptosis↑	Zhang et al. (2010)
T. hemsleyanum Flavones	SW620 cells	0.25–1 mg/mL	Cell proliferation↓, cle-caspase-3↑, cle-caspase-9↑, Bax↑, Bcl2↓	Wu et al. (2016)
Petroleum Ether Fraction of T. hemsleyanum	Hela cells	10–40 μg/mL	Caspase-3↑, caspase-8↑, caspase-9↑, CAT↓, SOD↓, GSH-pX↓, MDA↑	Xiong (2015)
Enhancing immune function
Total flavonoids of T. hemsleyanum	C57BL/6 mice inoculated lewis lung carcinoma cells	5–15 mg/kg (p.o. for 14 days)	Tumor growth↓, regulatory T-cell development↓, TGF-β↓, PGE2↓COX2↓	Feng et al. (2014)
T. hemsleyanum Flavones	C57BL/6 mice inoculated lewis lung carcinoma cells	7.5–30 mg/kg (i.g. for 14 days)	Tumor volume↓, TGF-β↓, PGE2↓, COX2↓	Feng et al. (2014)
T. hemsleyanum Flavones	C57BL/6 mice inoculated lewis lung carcinoma cells	3.125–12.5 mg/kg (i.g. for 14 days)	PGE2↓, COX2↓	Zhang and Feng (2017)
T. hemsleyanum Flavones	C57BL/6 mice inoculated Lewis lung cancer cells	5–20 mg/kg (i.g. for 14 days)	Arg-1↓, iNOS↓, MDSCs(GR-1+ CD11b+)↓, proportion of CD8+ T cells↓, CD4+T cells↑, ratio of CD4+T/CD8+T↑	Hu et al. (2018)
T. hemsleyanum Flavones	C57BL/6 mice inoculated Lewis lung cancer cells	7.5–30 mg/kg (i.g. for 23 days)	The proportion of Treg cell↓, CD152↓	Zhang and Feng (2017)
Ethylacetate extract of T. hemsleyanum	C57BL/6 mice inoculated Lewis lung cancer cells	5–25 g/kg (i.g. for 14 days)	Tumor weight↓, spleen index↑, thymus index↑, IFN-γ↑, TNF-α↑	Li et al. (2012)
Polysaccharide of T. hemsleyanum aerial part	BALB/c mice inoculated with 4T1 cells	50–250 mg/kg (i.g. for 14 days)	Tumor volume↓, liver index↓, CD4+↓, CD25+↓, Foxp3+↓, Treg cells↓, the proportion of CD3+/CD4+↑, CD3+/CD8+ ↑, CD4+/CD8+ ↑	Guo et al. (2019)
T. hemsleyanum and its formula with ginseng or curcuma wenyujin	615 mice inoculated MFC cells	2.25–2.70 g/kg (i.g. for 22 days)	Tumor volume↓, Treg ratio↓, COX-2↓, PGE2↓	Feng et al. (2014)

Enhancing immune function

It has been well documented that the promotion of body immunity played a pivotal role in cancer development and treatment (Neil et al., 2008; Hinrichs and Rosenberg, 2014). Regulatory T cells (Tregs) have significant functions in the regulation of immune responses (Fig. 7 ). Tregs can express CD4, CD25 and Foxp3, which are associated with solid tumors. The inhibiting effect of Tregs on other CD4T cells and cytotoxic CD4T cells depends on intercellular communication and the secretion of inhibitory cytokines such as transforming growth factor beta (TGF-β). TGF-β induces the expression of cyclooxygenase 2 (COX2), and the overexpression of COX2 secretes high levels of PGE2. PGE2 significantly up-regulates the expression of the Treg cell-specific transcription factor forkhead/winged helix transcription factor gene (Foxp3) in CD4+ and CD25+ T cells. Thus, the induction, maintenance and function of the Tregs are closely related to COX2-PGE2 pathway. Numerous studies have shown that T. hemsleyanum could decrease the expression of PGE2, COX2 and TGF-β, down-regulate the proportion of CD4+, CD25+, Foxp3+T and Tregs, consequently improve the immunosuppressive state of tumor patients or animals, enhance the immune function of the body and achieve the anti-tumor effect (Feng et al., 2014a, Feng et al., 2014b, Feng et al., 2014c; Feng et al., 2014; Zhang and Feng, 2017a, Zhang and Feng, 2017b; Hu et al., 2018; Zhang and Feng, 2017, 2017; Li et al., 2012; Guo et al., 2019; Feng et al., 2014).

Fig. 7

The role of Treg cells, PGE2, COX2 and TGF-β in tumor cell immunity.

Toxicology

More and more attention has been paid to the toxicological study of T. hemsleyanum. Jiang made a toxicological evaluation on the decoction of T. hemsleyanum root tuber according to the dosage for folk clinical use was 15 g/person/day, and results indicated that the oral LD50 of rats and mice was more than 100 g/kg and 40 g/kg, respectively (Jiang and Guo, 2005). Furthermore, after feeding with T. hemsleyanum root tuber at 6.25, 12.5 and 25.0 g/kg daily for 30 days, there was free of mortality and toxicity, which demonstrated that the long-term use of T. hemsleyanum root tuber was safe and non-toxic (Jiang and Xu, 2005). The acute toxicity test of crude extracts of T. hemsleyanum aerial parts showed that the maximum tolerated dose given by intragastric administration in mice could reach as high as 80.4 g/kg/d, which was equivalent to 321.6% of the daily dose of 60 kg of human body weight. During the 14 day observation period, no toxic reaction, no animal death and no other abnormal changes about blood and biochemical indexes, organ coefficient and organ pathology were found (Chen et al., 2017). Besides, it also had been proved that the oral toxicity of T. hemsleyanum aerial parts formula granules was small, the maximum tolerable dose of gavage was more than 30.4 g/kg/d, and it was safe and reliable in clinical dosage (Xie et al., 2019).

Conclusion and future perspectives

T. hemsleyanum is an excellent medicinal plant containing bioactive constituents, which have been linked to its traditional application, such as anti-febrile convulsion, anti-pneumonia, anti-hepatitis, anti-upper respiratory infection, anti-asthma, anti-traumatic injury, antitumor. Available pharmacological studies on compounds and crude extracts indicated broad biological effects of T. hemsleyanum, providing basic evidences for traditional uses. Although the present review comprehensively summarized the knowledge on the botany, traditionally and ethnobotanical uses, phytochemistry, pharmacology and toxicity of the T. hemsleyanum, there are some gaps still require scientific evaluation and exploration.

First, a large number of studies focused on the verification of traditional pharmacological activities by now, while the phytochemical analysis of the assessed extract was lack, and the functional components were unknown. As is known to all, TCM generally contains extremely complicated phytochemical components, and different medicinal parts contain different kinds of chemical components. Different phytochemical profiles of herbs may result in different potencies in biological assessments, and the synergistic effect of different components may also affect their pharmacological activities. Therefore, phytochemical analyses are indispensable to determine the correlation between components and pharmacological activities with the aim of discovering promising precursors for the clinical drug development. Additionally, the lack of sample preparation method, or inaccurate use different part of TCM could result in low reproducibility of the reported pharmacological effects. Moreover, the identification of T. hemsleyanum has not been described in some studies and no voucher number has also been reported, so that the taxonomic validity of the voucher specimen cannot be validated. Some studies did not mention the identification methods and the detailed information (including location, collection date, developmental stage, plant or plant parts, collector, etc) of the T. hemsleyanum.

Second, some current findings have been assessed with some problems concerning their pharmacological methods and experimental designs. Some methods used in pharmacological activities of T. hemsleyanum do not have an appropriate design due to the lack of a positive control group, which makes the results less reliable. Additionally, few of the in vitro studies mentioned the passage number and population doubling time (PDL) of the cell line used. Regarding the tests on animal models, few study described complete data regarding compliance with regulations on the ethical treatment of experimental animals, including the institutional committee or organization that approved the design of the experiments. Furthermore, some pharmacological studies above-mentioned assessed the pharmacological activities only using a simple cell line or animal model without further investigating the underlying mechanisms of action. Moreover, the characteristic mode of “multi-component, multi-target, integrated adjustment” of TCMs urgently needs further pharmacological research to fully clarify.

Third, the reliability of T. hemsleyanum for treating poor joint flexure and extension, irregular menstruation of women, rheumatic arthralgia, viral meningitis, bruise and eczema has been confirmed by long-term clinical practice, but current findings are not enough to verify and elucidate these traditional uses from the perspective of modern pharmacology. Moreover, data on many aspects of T. hemsleyanum, such as acute and chronic toxicity, pharmacokinetics, quality control standard and the clinical value of active compositions is still limited which call for further study in order to establish safety and toxicological limits and provide guidance for clinical applications.

In conclusion, the information of T. hemsleyanum on the traditional usages, origin, chemical constituents, pharmacological activities, and toxicology has been comprehensively shown to make people more aware of T. hemsleyanum and promote its further investigation for the development of new herbal medicine and health products.

Author contributions

Ji T. performed experiments, analyzed data, and prepared the manuscript. Ji W. W. and Wang J. participated in analysis of data and preparation of the manuscript. Chen H. J. participated in pharmacological studies and data analysis. Cheng K. J., Qiu D. and Yang W. J. provided the samples and did help in the manuscript preparation. Furthermore, as the guarantor of this work, Peng X. designed and supervised the overall study and prepared the manuscript. They had full access to all available data and took responsibility for the integrity and the accuracy of the data in this study.

Declaration of competing interest

The authors declare no conflict of interest pertaining to this manuscript.