Withania frutescens. L Extract: Phytochemical Characterization and Acute and Repeated Dose 28-Day Oral Toxicity Studies in Mice.

BACKGROUND: Withania frutescens. L (W. frutescens) is a perennial woody medicinal plant belonging to family Solanaceae largely used by the indigenous population to Morocco for the treatment of disease.
OBJECTIVE: The purpose of this study was to investigate the chemical composition, acute, and subacute toxicity of W. frutescens extract in mice.
MATERIALS AND METHODS: The phytochemical composition of W. frutescens extract was determined using a gas chromatograph (GC/MS). Acute toxicity study was carried out in mice through oral administration of single doses 500 mg/kg, 1000 mg/kg, and 2000 mg/kg for 14 days. Subacute toxicity was performed with oral administration of repeated doses 500 and 2000 mg/kg/day for 28 days. Biochemical parameters (alanine aminotransferase, aspartate aminotransferase, urea, and creatinine), as well as histopathological changes potentially occurred in organs, (liver, kidney, and spleen) were evaluated.
RESULTS: The results of chromatographic analysis showed the richness of W. frutescens extract in interesting phytochemical compounds majorly constituted of bicyclo[3.1.1]heptane, 6,6-dimethyl-2-methylene-(C10H16). Regarding acute toxicity study, the results showed no clinical symptoms occurred in treated mice compared to the control group and no histological changes detected in analyzed organs of treated mice with dose put to 2000 mg/kg nor adverse effect on biochemical parameters.
CONCLUSION: The outcome of this work showed no toxic effect of W. frutescens in mice up to dose 2000 mg/kg bodyweight. Therefore, this study could scientifically validate further traditional use with safety in the range of tested doses.

1. Introduction

Plants possess the ability to synthesize, through complex metabolic pathways many bioactive compounds that play a crucial role in their adaptive functions versus climatic conditions. Plants contain a wide variety of phytochemical molecules (polyphenols, alkaloids, and so on) with different biological and pharmacological properties (antitumour, antiviral, antimicrobial, antioxidant, healing, and so on). Plants are an important source of bioactive molecules. Nowadays, the search for new natural drugs with fewer side effects is highly appreciated. However, the use of phytochemical compounds without scientific proof could negatively affect human health through potential toxic effects. To achieve this goal, overall approaches adopted at verifying the scientific validity of plants or their derivatives were used in traditional medicine. The huge use of plants in traditional medicine can be explained by sociocultural factors inherited from the early people or inaccessibility to modern medicine for medication due to high costs [1]. However, the use of plants for medication without scientific validly reporting on toxic profiles of plants can cause serious issues for human health [2]. The toxicological study is necessary to determine potential toxic doses of plant or their derivatives. Several factors may influence that toxicological profile should be taken into account including the growth stage and maturity of plants and plant parts used (leaves, roots, bark, flowers, seeds, etc.) and storage conditions of products (freshly harvested or stored for a long time), as well as seasonal variation of phytochemical content [3].

W. frutescens is a perennial woody medicinal plant systematically placed within the Magnoliophyta division, class Magnoliopsida, order Solanales, family Solanaceae, and genera Withania. This plant is very higher in bioactive chemical classes like tannins, mucilage, terpenoids, saponins, flavoinds, and polyphenols. W. frutescens has been widely used by the indigenous population against intoxication [4], as other studies reported their pharmacological properties (antioxidant, antimicrobial, and antifungal) [5]. Genus Withania is widely used in traditional medicine for the treatment of stress, inflammation, conjunctivitis, tuberculosis, and many other infections [6-10] and exhibited immunomodulatory effects on animal models as reported in the earlier data [11-15]. To the best of our knowledge, no early literature investigated the toxicity assessment of W. frutescens and therefore the current research was undertaken to screen its phytochemical composition as well as its toxicological profile in mice.

2. Materials and Method

2.1. Plant Material

Withania frutescens was collected during the period of March-April 2018 (the season when development and flowering are at their peak), 34.01300500° N; 4.75206833° W. Botanical identification was carried out by Professor Amina Bari (Faculty of Sciences, Department of Biology, Fez-Morocco), and the voucher specimen has been deposited under reference BPRN69. The roots of W. frutescens were washed and dried at room temperature (25 ± 2°C). The powder obtained was extracted by hydroethanolic maceration with 70% ethanol and 30% distilled water (W/V : 1/10) for 24 hours [16].

2.2. Phytochemical Analysis

The phytochemical identification of W. frutescens extract was done by a gas chromatograph (GC/MS). 0.003 g of W. frutescens extract was obtained by adding 200 μl of N-methyl-N-trimethylsilyl tri fluoroacetamide (MSTFA), then heated at 37°C for 30 min. 0.1 μl of this extract was injected for analysis. The analysis was carried out using a gas chromatograph coupled to a mass spectrophotometer (GC-MS) (Model 5973 from Brand Agilent Technologies). Helium was used as a carrier gas with a typical pressure range (psi) of 0.9 ml/s. The furnace temperature program was 70-270°C at 4°C/min and maintained at 270°C for 20 min. The temperature of the injector was set to 280°C and that of the detector to 290°C. The injection was carried out in fractionated mode [17].

2.3. Animal

Swiss albino mice weighing between 22 and 25 g obtained from the pharmacology laboratory of the Faculty of Sciences, Department of Biology, Fez-Morocco, were used to perform the study. The animals were divided into groups with 5 in each and kept in cages for acclimatization under laboratory conditions (temperature 20-22°C, photoperiod of 12 hours of light) for 7 days [18]. The procedures used in the current research work are in accordance with the internationally accepted guidelines for care and use laboratory animals. The Animal Ethics Review Committee of the Faculty of Sciences of Fez, Morocco, reviewed and approved this study.

2.4. Preparation of Test Solutions

The extract was dissolved in distilled water, then the mixture was homogenized by stirring (3-5 min) with a magnetic stirrer. The solution obtained was kept in a closed plastic jar and placed in a refrigerator after each use. The volume of solution chosen to be administered to animals was determined by the following formula:

where V = volume of solution chosen to be administered (ml); D = dose (mg/kg); P = weight of animal (kg); C = concentration of solution chosen to be administered (mg/ml).

2.5. Acute Oral Toxicity

This experimental study was conceptualized according to the guideline 423 (OECD, 2001) [19]. Animals were divided into 4 groups with 5 mice in each. Doses 500 mg/kg, 1000 mg/kg, and 2000 mg/kg were chosen to be orally administered to treated mice by the time the control group received physiological solution (vehicle) after fasting for 18 h under acute toxicity conditions according to the earlier protocols. Afterward, animals were placed under monitoring for recording immediate clinical symptoms then daily for 14 days [20].

2.6. Subacute Oral Toxicity

Subacute toxicity study was conducted according to OECD, 1998, Guideline No. 407 [21]. After devising the animals into 3 groups with 5 mice in each, treated groups daily received 500 mg/kg (group II) and 2000 mg/kg (group III) by the time the control group (group I) received physiological solution (vehicle) for 28 days. Signs and symptoms of toxicity were observed for 28 days, and body weight was measured weekly. On day 28, the animals were sacrificed after anesthesia for blood and organ collection. Organ weights were estimated to calculate the relative weight of organs [22].

2.7. Relative Organ Weights (ROW)

The relative weight of spleen, liver, and kidney excised from treated animals was calculated using the following formula [23]:

2.8. Analysis of Serum Biochemistry

The biochemical analysis of serum was performed at the end of the experimental period. The blood was transferred into heparin tubes then centrifuged at 3500 rpm for 10 minutes. The serum was recovered and stored into tubes for analysis. Creatinine, urea, aspartate aminotransferase (ASAT), and alanine aminotransferase (ALAT) were evaluated using an automated analyzer.

2.9. Histopathological Evaluation

At the end of the experimental period, animals were anesthetized and sacrificed by cervical dislocation. Afterward, organs were excised and weighed in order to calculate the relative weight of organs. Vital organs such as kidney and liver were preserved in 10% formalin for histopathological analysis [24].

2.10. Statistical Analysis

Data were expressed as means ± SEM (five replicates). Statistical significance was determined using the ANOVA test. The difference was considered to be statistically significant when p < 0.05.

3. Results and Discussion

3.1. Identification of Phytochemical Composition of W. frutescens Root Extract by GC-MS

The phytochemical identification of the plant extract studied in this work revealed the presence of interesting phytochemical compounds. The chromatographic profile showed the peaks of compounds present in the extract studied with a retention time of identified compounds (Figure 1 and Table 1).

Figure 1

Chromatographic profile of phytochemical compounds of W. frutescens extract.

Table 1

Identification of phytochemical compounds contained in the W. frutescens root extract.

Peak	RT	Phytochemical compounds identify	Area (%)
1	15.087	3,3,6-tTrimethyl-1,4-heptadien-6-ol (C10H18O)	2.54
2	14.151	Tricyclo[2.2.1.0(2,6)]heptane-3-methanol, 2,3-dimethyl-(C10H16O)	1.14
3	13.280	Bicyclo[3.1.0]hexan-3-one, 4-methyl-1-(1-methylethyl)-, [1S-(1α,4β,5α)]-(C10H16O)	2.35
4	12.983	Bicyclo[2.2.1]heptan-2-ol, 1,7,7-trimethyl-(C10H18O)	4.84
5	12.782	Bicyclo[3.1.1]heptan-3-ol, 2,6,6-trimethyl-, (1α,2β,3α,5α)-(C10H18O)	0.82
6	11.525	2,6-Octadien-1-ol, 3,7-dimethyl-, (Z)-(C10H18O)	2.04
7	11.035	2,6-Octadien-1-ol, 3,7-dimethyl-, (E)-(C10H18O)	0.99
8	10.931	Benzene, 1-ethyl-2,3-dimethyl-(C10H14)	1.26
9	10.790	Benzene, 1-methyl-3-(1-methylethyl)-(C10H14)	1.33
10	9.698	Bicyclo[2.2.1]hept-2-ene, 1,7,7-trimethyl-(C10H16)	4.56
11	9.377	Bicyclo[2.2.1]hept-2-ene, 2,7,7-trimethyl-(C10H16)	10.19
12	9.100	Bicyclo[3.1.1]heptane, 6,6-dimethyl-2-methylene-, (1S)-(C10H16)	28.48
13	7.855	Tricyclo[2.2.1.0(2,6)]heptane, 1,7,7-trimethyl-(C10H16)	3.90
14	5.028	Thiophene, 3-phenyl-(C10H8S)	0.76
15	4.952	Methanamine,N,N-di(2-trimethylsilyloxyethyl)-(C11H29NO2Si2)	34.12
16	4.852	Silanamine, N,1,1,1-tetramethyl-N-(trimethylsilyl)-(C7H21NSi2)	0.66
Total			99.98

Gas chromatographic analysis showed more than 16 compounds identified in the extract with different percentages such as 28.48% bicyclo[3.1.1]heptane, 6,6-dimethyl-2-methylene and 34.12% methanamine,N,N-di(2-trimethylsilyloxyethyl). The latter was dominant bioactive compounds in the root extract besides other compounds with low percentages of 4.56% bicyclo[2.2. 1]hept-2-ene, 1,7,7-trimethyl; 4.84% bicyclo[2.2.1]heptan-2-ol, 1,7,7-trimethyl; 10.19% bicyclo[2.2.1]hept-2-ene, 2,7,7-trimethyl; and 3.90% tricyclo[2.2.1.0(2,6)]heptane, 1,7,7-trimethyl. The compounds revealed by GC-MS as well as their percentage are presented in Table 1. The difference in the percentage of detected compounds could be due to the presence of volatile phytochemical compounds that are easily identified by gas chromatograph (GC/MS). The solvents used in this method can produce new chemical compounds with an insignificant percentage. According to the earlier phytochemical identification, Withania frutescens is known for its phytochemical richness [16] and pharmacological properties (anti-inflammatory, analgesic, antimicrobial, and antifungal) [25] and biological properties (antioxidant power) [5].

3.2. Acute Toxicity

The bodyweight of animals and physical appearance are preliminary factors that could be used to identify toxic effects occurred in mice treated with extract [26]. The body weight of mice treated with 500, 1000 mg/kg, and 2000 mg/kg was not adversely affected during the experimental period of dosing (14 days) (Figure 2). No clinical symptoms occurred in mice treated with 500 nor those treated with 1000 mg/kg (diarrhoea, immobility, excitement, contortion, refusal of food, trembling, and mortality). Animals received 2000 mg/kg got relaxed during the first 40 minutes followed the gavage. This effect could be due to the fact that the family solanaceous and specifically the genus Withania induce relaxation effects on treated mice as reported in the earlier data. Genus Withania could be considered as a promising source of adaptogenic and antistress substances [10], which was also recorded for treated mice with 2000 mg/kg in the current work.

Figure 2

Effects of acute administration on body weight after 14 days of treatment with W. frutescens. L extract.

4. Subacute Toxicity

4.1. Clinical Observations and Body Weight

During the whole experimental period of dosing (28 days), animals were placed under observation for recording toxicity signs. Thus, no adverse effect noticed nor behavioral changes appeared on treated mice with dose up to 2000 mg/kg/day; however, animals got relaxed after 25 minutes of gavage for about three hours and that was recorded from day 4 until the end of the experimental test. All treated animals gained weight during the whole period of treatment. Therefore, that could confirm the safety of the extract tested on treated mice since no weight alteration was observed (Figure 3).

Figure 3

Effects of subacute administration on body weight after 28 days of treatment with W. frutescens extract.

4.2. Relative Organ Weights

After 28 days of administration of the extract, the mice were sacrificed for collection of organs such liver, kidney, and spleen and were weighed to calculate the relative weight of each. The relative weight of the kidney and liver and spleen excited from treated animals showed no significant change compared to the control group (p > 0.05) (Figure 4). These findings were in accordance with the earlier data as reported that the administration of either natural or chemical toxicants to animals may cause a decrease in their internal organ weight [27] and therefore we can confirm the safety of the extracted tested in the animal at a dose up to 2000 mg/kg/day.

Figure 4

Relative weight of kidney and liver and spleen organs after 28 days of treatment with the extract.

4.3. Effects of Withania Frutescens Extract on Biochemical Parameters

The results of biochemical parameters showed no significant change in alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), urea, nor creatinine of treated mice with 500 mg/kg and 2 mg/kg body weight under subacute toxicity conditions (p > 0.05) (Figure 5). These findings could confirm the safety of W. frutescens extract at dose up to 200 mg/body weight since any significant increase in transaminase activities could be explained by potential liver damage; otherwise, the increase in urea and creatinine concertation is frequently induced by kidney alteration [12, 13].

Figure 5

Effect of W. frutescens extract on animal biochemical parameters ((a) urea, (b) creatinine, (c) ASAT, and (d) ALAT). Values are expressed as mean ± SEM, n = 5; ns: not significant; p > 0.05; ∗p < 0.05; ∗∗p < 0.01; ∗∗∗p < 0.001.

4.4. Histology Evaluation of Animal Organs

The histological study of the liver tissue showed no histological alteration in the liver tissue after analyzing liver section of animals treated with 500 and 2000 mg/kg for 28 days for potential changes in cell architecture, bile ducts, hepatic vein, and artery, as well as hepatic fat (Figure 6). Figure 7 shows that the kidney tissues of mice received the extract remained normal without morphological changes in cortex, distal tubule, proximal tubule, and glomerulus compared to the control group which received a vehicle (distilled water). No histological changes were detected in all treated groups with doses 500 and 2000 mg/kg. The spleen is an organ that regulates the formation and destruction of red blood cells and has a role in the storage of red blood cells, lymphocytes, and other figurative elements of blood. Morphological comparison of spleen tissue of treated mice with dose up to the maximum (2000 mg/kg) showed no histological change compared to the control group. These histopathological findings were in agreement with those of biochemical parameters that showed no change in AST, ALT, urea, nor creatinine Figure 8.

Figure 6

Photomicrographs of liver slices of animals after 28 days of extract administration (hematoxylin/eosin, X 40).

Figure 7

Kidney histology of animals treated with 500 mg/kg, 2000 mg/kg, and control (hematoxylin/eosin, X 40).

Figure 8

Microscopic photo of spleens of animals receiving the ethanolic extract of W. frutescens (hematoxylin/eosin, X 40).

Transaminases or aminotransferases are enzymes that catalyze the transport of alpha-amino radicals from alanine and aspartic acid to alpha-ketoglutaric acid. Transaminases found normally in the liver, muscle, kidney, pancreas, and other tissues. These enzymes are commonly synthesized in the cytoplasm of cells and discharged into blood circulatory when cells get damaged [28]. A plasmatic increase of transaminase activities frequently results in cases of myopathy, rhabdomyolysis, or myocardial infarction and hemolysis [29]. Analysis of urea and creatinine of treated mice with the plant extract in this work revealed no significant change in their values compared to the control group. These results could confirm the safety of the extract in mice up to doses tested since the plasmatic increase of urea and creatinine is considered a primary marker of nephrotoxicity [30]. The results of acute toxicity of root extract showed no toxic effect on the serum parameters nor the behavior of animals were effected as also confirmed by the histological examination that showed the absence of morphological and structural changes in excised organs from treated mice. The use of this species in traditional pharmacopoeia against intoxication could mean that the plant has an ancient pharmacological potential [4]. The traditional use of W. frutescens could be safe since the plant extract was tested negative for potential toxic in mice at dose up to 2000 mg/kg. Genus Withania exhibits adaptogenic and antistress activities with lower doses than those investigated in this work. The adaptogenic activity of standardized extract of W. somnifera roots was studied against chronic stress in animal with promising results. Therefore, the roots studied could be used in the treatment of some clinical diseases especially since W. somnifera roots has been classified belonging the plant drugs known to promote physical and mental health, increase the body's resistance to disease and various adverse environmental factors, revitalize the body versus debilitating conditions, and increase the longevity [10].

5. Conclusion

The use of plants in the treatment of some diseases remains dangerous without scientific validity. The outcome of the present study showed no toxic effect on treated mice with W. frutescens up to the maximum dose (2000 mg/kg). This study was considered as a preclinical step for further phytotherapeutic use of W. frutescens without potential adverse effects when used at a dose up to 2000 mg/kg.