Ethnomedicinal assessment of Irula tribes of Walayar valley of Southern Western Ghats, India.

The present study was aimed to explore the traditional knowledge of Irula tribal people who are practicing herbal medicine in Walayar valley, the Southern Western Ghats, India. A total number of 146 species of plants distributed in 122 genera belonging to 58 families were identified as commonly used ethnomedicinal plants by them. Interestingly, 26 new claims were also made in the present study. Through the data obtained from Irula tribal healers, the herbs were mostly used for medicine (40.4%) followed by trees (26.7%) and climbers (18.5%). In addition leaves were highly used for medicinal purposes, collected from 55 species (38%) followed by multiple parts from 18 species (12%). Acorus calamus is the species of higher use value (1.80) assessed to be prescribed most commonly for the treatment of cough. High informant consensus factor (1.0) obtained for insecticidal uses and cooling agent indicates that the usage of Canarium strictum and Melia dubia, and Mimosa pudica and Sesamum indicum respectively for that purposes had obtained high degree of agreement among the healers in using these species for the respective purposes. The most commonly used method of preparation was decoction (63%) followed by raw form (23%), paste (12%) and powder (2%). Therefore, it is suggested to take-up pharmacological and phytochemical studies to evaluate the species to confirm the traditional knowledge of Irulas on medicinal plants.

Introduction

Since few centuries, it is reported that about one fourth of the common drugs used worldwide are derived from plants (Ernst, 2005). Among the top 252 common formulations of the drugs, 219 are obtained from plants alone (Dobson, 1995). As the indigenous people are the more reliable source of information on medicinal plants (Iwu et al., 1999), for the past few decades, use of ethnobotanical information in medicinal plant research has gained great attention among the scientific community (Heinrich, 1999). Documentation of ethnobotanical species for further scientific validation and subsequent processing for commercialization in India are also getting importance in recent decades (Venkatasamy et al., 2010, Arunachalam and Parimelazhagan, 2011, Ayyanar and Ignacimuthu, 2011, Senthilkumar et al., 2013, Pushpakarani and Natarajan, 2014). India, the megabiodiversity nation is not only endowed with a variety of flora and fauna but also has several ethnic communitiesv. By practicing and using the plants for thousands of years, the ethnic and aboriginal people have gained immense practical knowledge about the medicinal plants (Pullaiah et al., 2003).

Western Ghats, the biodiversity hotspot and medicinal plants emporium of India harbours about 3500 plant species of therapeutic importance, and many of them are still used by several tribal communities for their health care particularly for first aid remedies (Abraham, 1981; Nair and Jayakumar, 2003). Richness of medicinal plants in the Western Ghats parts of Coimbatore and Nilgiri districts of Tamil Nadu is high due to the existence of varied types of ecosystems in this landscape (Ramachandran, 2007). Irulas, Thodas, Malasars, Muduvas and Puliars are the major tribal communities in this part doing effective medical practice by using plants (Paulsamy, 2004). However, few reports on ethnobotanical information without much quantitative analysis are only available for this region (Umapriya et al., 2011, Rasingam, 2012). Assessment of information on medicinal plants provided by tribal healers is most required as it gives additional support to know the level of healing property of plants. Irulas, one of the 615 tribal communities of India are living in different topographic habitats (plains, mountains, valleys etc. in Tamil Nadu) and also in the Walayar valley and foothills of Siruvani hills of Southern Western Ghats (Edgar, 1909). Using plants for their day-today health problems is the common medical practice among them (Karthikeyani, 2003). Despite this ethnobotanical significance, no reports are available on medicinal plants used by the Irulas of Walayar valley. To address this lacuna, documentation and quantitative analysis were made in Walayar valley, among the Irula tribals to explore their traditional knowledge on plants for medicinal uses.

Materials and methods

Study area and the tribal community

The study area, Walayar Valley, located in lower Western Ghats of Coimbatore district, Tamil Nadu State and Palghat district, Kerala State and the Palghat gap of both States covers an area of ca.12500 ha (ca. 4200 ha in Tamil Nadu and 8300 ha in Kerala) between the altitude 370 and 450 m above msl. The geographical location of Walayar valley is 10° 77′ 0-3″ N and 76° 51′ 06-10″ E (Fig. 1). In this landscape, ca. 55% of the geographical area occupied by moist tropical semi-evergreen forest dominated by the tree species, Chloroxylon swietenia (Champion and Seth, 1968) is a protected forest for biodiversity conservation. The only inhabitant, Irula tribal community is permitted to do agriculture and collection of minor forest produce for their own use without posing any problem to species diversity. The Walayar river runs across the valley and its environ occupies ca. 2% of geographical area of this region. The agricultural land around the forests in this valley spreads over an area of ca. 40% of total geographical area. Annual rainfall ranges between 1500 and 2200 mm for the past 15 years.

Figure 1

Location of study area, the Walayar valley.

The population of Irula tribals in Walayar valley is ca. 470, distributed in six hamlets each consists of 6–15 families. According to anthropological literature, Irula, one of the oldest tribal communities of India belongs to the Negrito race (migrated from Africa) which is one among the six ethnic groups that add to the racial mosaic of India (Von, 1982). Few elders in this community have the knowledge on medicinal uses of plants which are used mainly for first aid remedies like stomach problems, fever, headache, skin problems, etc.

Data collection

Six field visits were made in Walayar valley for getting ethnobotanical information during the period between October, 2013 and May, 2015 in all the six Irula habitations. Totally five ageold healers of in-depth knowledge on medicinal plants were identified for collecting information by interrogations. To determine the difference in knowledge among the Irula people, we cross checked the information collected with the other informants. The number of times, the healers repeated the same use of the plants was noted. For documenting the ethnobotanical information, field data sheet has been prepared and used. Local name of the plant, parts used for treatment, preparation methods, other plants used as ingredients, mode of administration etc., were collected for all medicinal plants used by Irulas. The plant species were identified with the help of keys provided in ‘The Flora of Presidency of Madras’ (Gamble and Fischer, 1935) and ‘The Flora of Tamil Nadu Carnatic’ (Matthew, 1983). Identified species were confirmed with Dr. V. Balasubramaniam, Plant Taxonomist in the Botany Department of Kongunadu Arts and Science College, Coimbatore. Herbarium specimens are maintained in the Botany Department of the College.

Ailment categories

Sixteen ailment categories were grouped (Cook, 1995) as presented elsewhere (Venkatachalapathi et al., 2016) on basis of the information provided by the Irula healers of Walayar valley.

Analysis of data

Informant consensus factor (F) was used to know the level of consensus among the informants or healers on the use of a plant for a particular ailment category. The Use Value (UV) is importance of a species in terms of its use in herbal remedy in relation to other species. Fidelity level (FL) is a tool to determine the most frequently used plant species as per the informants for the treatment of a disease in a particular ailment category. The UV, F and FL were calculated as per the formula of Trotter and Logan, 1986, Phillips et al., 1994 and Friedmen et al. (1986) respectively.

Results

The Irula tribes of Walayar valley utilized a large number of 146 species of 122 genera belonging to 58 families for the treatment of various medicaments (Table 1). One of the interesting observations made in the study is that among the 146 ethnomedicinal plants, 26 claims from the species like Acacia leucophloea, Alstonia venenata, Artocarpus heterophyllus, Carissa spinarum, Curculigo orchioides, Hybanthus enneaspermus, Melia dubia and Solena amplexicaulis etc. are new and are reported for the first time (Table 1). Among the medicinal plant families represented, Fabaceae registered more number of 16 species followed by Euphorbiaceae (9 species), Lamiaceae (7 species) and Asclepiadaceae (6 species). Through the data obtained from life-form analysis, incidence of herbs (40.4%) were the primary source of medicine followed by trees (26.7%) and climbers (18.5%) (Fig. 2). In addition, among the utilization of various plant parts investigated, leaves of greater number of 55 species followed by whole plant (16 species), fruits (13 species) and rhizomes (12 species) were used by the tribal community for the treatment of common ailments such as cold, cough, jaundice, rheumatism etc. (Fig. 3). However, 18 species were exploited for their multiple usage in herbal remedy. They were administered either alone or in combination with parts of other species (Table 2). Generally, they were prescribed as decoction (63%), raw form (23%), paste (12%) and powders (2%) (Fig. 4).

Table 1

List of medicinal plants used by the Irula tribal community in Walayar valley of Coimbatore district, Southern Western Ghats, India.

S. No.	Botanical name and family	Local name	Use value	Parts used	#Ailment category: number of use reports (ailments treated)	Preparation	Application
1	TreesAcacia catechu Willd. (Mimosaceae)	Karungali	0.60	Stem	GIA-1 (ulcer) RSD-1 (chest pain) SMSD-1(swelling)	DecoctionDecoctionDecoction	OralOralOral
2	∗,†A. leucophloea (Roxb.) Willd. (Mimosaceae)	Vellvale maram	1.40	Bark	DID-4 (wound healing) GIA -3 (stomach problem)	RawDecoction	TopicalOral
3	†A. nilotica (L.) Willd. (Mimosaceae)	Karuvale maram	0.20	Stem and bark	DC-1 (toothache)	Past	Toothpaste
4	Aegle marmelos (L.) Corr. (Rutaceae)	Vilvam	0.60	Leaf and fruit	ED-1 (diabetes) Fvr-1 (fever) DID-1 (antiinflammatory)	Raw DecoctionDecoction	OralOralOral
5	†Ailanthus excelsa Roxb. (Simaroubaceae)	Perumaram	0.20	Leaf	GUA-1 (menstrual problem)	Decoction	Oral
6	†Alangium salviifolium (L.f.) Wangerin. (Alangiaceae)	Alangi	0.80	Leaf and stem	GIA-2 (stomach ache) RSD-2 (chest pain)	RawDecoction	OralOral
7	∗,†Albizia amara ROXB. (Fabaceae)	Arappu	1.20	Leaf	HC-6 (dandruff)	Raw	Oral
8	†A. lebbeck (L.) Benth. (Fabaceae)	Vagai	0.20	Leaf	DID-1 (eczema)	Raw	Oral
9	∗,†Alstonia venenata R. Br. (Apocynaceae)	Sinnappalai	0.20	Latex	DID-1 (wound)	Raw	Oral
10	∗,†Artocarpus heterophyllus Lam. (Rutaceae)	Pala	0.60	Leaf and fruit	SMSD-1(arthritis) DID-2 (antioxidant and skin diseases)	DecoctionRaw	OralOral
11	Azadirachta indica A. Juss. (Meliaceae)	Vembu	0.60	Whole plant	PB-1 (snake bite) CSCD-1 (blood purification) SMSD-1 (rheumatism)	Raw DecoctionDecoction	OralOralOral
12	†Canarium strictum Roxb. (Burseraceae)	Sambirani chedi	0.20	Bark	IC-1 (mosquito repellent)	Powder	Topical
13	†Canthium diococcum (Gaertn.) Merr. (Rubiaceae)	Payira maram	0.40	Leaf	PB-1 (dog bite) GIA-1(stomach ache)	DecoctionDecoction	OralOral
14	∗,†Carissa spinarum Linn. (Apocynaceae)	Chrukila	0.40	Fruit and latex	ENT-1 (mouth ulcer) DID-1 (antioxidant)	DecoctionRaw	OralOral
15	Cassia fistula Linn. (Caesalpiniaceae)	Kakke maram	1.00	Stem and flower	Fvr-2 (fever) GIA-2 (stomach pain) DID-1 (antiinflammatory)	DecoctionDecoctionDecoction	OralOralOral
16	†Cinnamomum camphora (L.) Nees & Eberm. (Lauraceae)	Pachkarpooram	0.20	Stem	ENT-1 (ear ache)	Decoction	Oral
17	∗,†Commiphora caudata Wight & Arn. (Burseraceae)	Kiluvai	0.80	Leaf	Fvr-4 (fever)	Decoction	Oral
18	∗,†Dalbergia sissoo Roxb. ex DC. (Fabaceae)	Ette	0.20	Stem	DID-1 (skin diseases)	Past	Topical
19	†Dodonaea angustifolia (L.f.) Benth. (Sapindaceae)	Baraley	0.40	Leaf and bark	SMSD-2 (Bone fracture and head ache)	Past	Topical
20	†Erythrina variegata (L.) Merr. (Fabaceae)	Mullumurungai	0.40	Leaf	RSD-2 (cold and cough)	Decoction	Oral
21	Ficus racemosa Roxb. (Fabaceae)	Athi	0.60	leaf, bark and fruit	CSCD-1 (blood secretion) GUA-1 (leucorrhoea) SMSD-1 (arthritis)	RawDecoctionDecoction	OralOralOral
22	∗Limonia acidissima L. (Rutaceae)	Vilampalam	0.60	Fruit	GUA-1 (leucorrhoea) DID-1 (antioxidant) SMSD-1 (arthritis)	RawDecoctionDecoction	OralOralOral
23	†Mangifera indica L. (Anacardiaceae)	Mavin mara	0.80	Leaf, bark and fruit	DID-2 (Wound healing and antioxidant) GIA-1 (menstrual problem) SMSD-1 (swelling)	RawDecoctionDecoction	OralOralOral
24	∗,†Melia azedarach L. (Meliaceae)	Malaivembu	0.60	Bark	GIA-3 (stomach ache)	Decoction	Oral
25	∗M. dubia L. (Meliaceae)	Malaivembu	0.60	Bark	IC-1 (mosquito repellent) ED-1 (diabetes) GIA-1 (stomach ache)	PowderDecoctionDecoction	TopicalOralOral
26	∗,†Mesua ferrea L. (Calophyllaceae)	Churuli	0.20	Flower	GIA-1 (stomach ache)	Decoction	Oral
27	†Moringa oleifera L. (Moringaceae)	Murungai	0.40	Leaf, flower and fruit	GUA-2 (male fertility)	Decoction	Oral
28	Phyllanthus emblica L. (Euphorbiaceae)	Nelli	0.60	Fruit	CSCD-1 (blood purification) DID-1 (antioxidant) HC-1 (hair tonic)	RawDecoctionDecoction	OralOralOral
29	†Pongamia pinnata L. (Fabaceaae)	Pungam	0.40	Seed	SMSD-2 (rheumatism)	Decoction	Oral
30	†Sapindus emarginatus Vahl. (Sapindaceae)	Pucha	0.60	Stem and fruit	SMSD-1 (head ache) GH-2 (piles and bathing)	DecoctionDecoction	OralOral
31	†Syzygium aromaticum (L.) Merrill & Perry. (Myrtaceae)	Kiraampu	0.60	Fruit	DC-3 (toothache)	Past	Toothpaste
32	†S. cuminii L. (Myrtaceae)	Naval	1.40	Leaf, bark, fruit and seed	ED-4 (diabetes) DID-2 (antioxidant) GIA-1 (dysentery)	RawRawDecoction	OralOralOral
33	†Tamarindus indica L. (Fabaceae)	Puli	0.40	Seed	PB-1 (scorpion bite) DID-1 (antioxidant)	DecoctionRaw	OralOral
34	†Terminalia arjuna (Roxb.) W. & A. (Combritaceae)	Marutu	0.20	Bark	RSD-1 (chest pain)	Decoction	Oral
35	†T. bellerica Roxb. (Combritaceae)	Thanikai	0.20	Bark	RSD-1 (chest pain)	Decoction	Oral
36	†T. chebula Retz. (Combritaceae)	Kadukkai	0.20	Fruit	GIA-1 (stomach pain)	Decoction	Oral
37	†Wrightia tinctoria R. Br. (Apocynaceae)	Palai	0.20	Leaf	DC-1 (toothache)	Past	Toothpaste
38	†Ziziphus mauritiana L. (Ramnaceae)	Elanthai	0.60	Leaf	DID-3 (wound)	Past	Topical
39	†Z. enophylla L. (Ramnaceae)	Malai elanthai	0.60	Leaf	DID-3 (wound)	Past	Topical
40	Shrubs†Argemone mexicana L. (Papaveraceae)	Kutiyotti	0.60	Latex	GIA-1 (ulcer) DID-2 (pimples and wound healing)	DecoctionRaw	OralOral
41	†Atalantia monophylla L. (Rutaceae)	Kattuelumichai	1.00	Fruit	SMSD-4 (body pain) DID-1 (antioxidant)	DecoctionRaw	OralOral
42	†Begonia malabarica L. (Begoniaceae)	Rattha choori	0.80	Whole plant	SMSD-4 (arthritis and joint pain)	Raw and Decoction	Oral
43	†Calotropis procera (Aiton) W.T.Aiton. (Asclepiadaceae)	Vella Erukku	0.20	Latex	DID-1 (wound)	Raw	Oral
44	†Cassia auriculata L. (Fabaceae)	Aavaarampoo	1.20	Flower	ED-6 (diabetes)	Raw and Decoction	Oral
45	†Citrus limon (L.) Burm. f. (Rutaceae)	Elumichi	0.20	Fruit	GIA-1 (dysentery)	Raw and Decoction	Oral
46	†Clerodendrum inerme (L.) Gaertn. (Lamiaceae)	Sangam	0.20	Leaf	DID-1 (skin diseases)	Decoction	Oral
47	†Helicteres isora L. (Sterculiaceae)	Valampuri edampuri	0.20	Fruit	ENT-1 (ear ache)	Decoction	Oral
48	†Jatropha gossypifolia L. (Euphorbiaceae)	Adalai	0.60	Latex	ENT-3 (mouth ulcer)	Decoction	Oral
49	†Justicia adhatoda L. (Acanthaceae)	Adatodai	1.20	Leaf	Fvr-6 (fever)	Decoction	Oral
50	†J. gendarussa L. (Acanthaceae)	Vadaikkutti	0.20	Leaf	SMSD-1 (body pain)	Decoction	Oral
51	∗,†Lantana camara L. (Verbenaceae)	Unnichedi	0.40	Leaf	DID-2 (wound healing and antiinflammatory)	Past / Decoction	Topical /Oral
52	†L. wightii L. (Verbenaceae)	Unnichedi	0.60	Leaf	DID-3 (wound healing)	Past	Topical
53	†Manihot esculenta L. (Euphorbiaceae)	Maravalli	0.20	Rhizome	DID-1 (wound healing)	Past	Topical
54	∗,†Pavetta indica L. (Rubiaceae)	Vellaippavattai	0.80	Leaf	PB-4 (snake bite)	Decoction	Oral
55	†Rauvolfia serpentina (L.) Benth. (Apocynaceae)	Amalpori	0.80	Leaf	PB-4 (snake bite)	Decoction	Oral
56	†R. trtraphylla L. (Apocynaceae)	Pampukaalaachchedi	0.60	Leaf	PB-3 (snake bite)	Decoction	Oral
57	∗,†Solanum surattense L. (Solanaceae)	Kandankathiri	1.20	Whole plant	RSD-6 (cold and wheezing)	Decoction	Oral
58	†Vitex negundo L. (Verbenaceae)	Notchi	1.40	Leaf	SMSD-7 (headache and body pain)	Decoction	Oral
59	Herbs†Abutilon indicum L. (Malvaceae)	Thuththi	0.80	Whole plant	GH-4 (piles)	Decoction	Oral
60	†Acalypha indica L. (Euphorbiaceae)	Kuppaimeni	0.20	Leaf	LP-1 (jaundice)	Decoction	Oral
61	†A. fruticosa L. (Euphorbiaceae)	Punairananki	0.20	Leaf	DID-1 (skin disease)	Past	Topical
62	†Achyranthes aspera L. (Ameranthaceae)	Nayuruvi	0.40	Whole plant	PB-2 (dog bite and poisonous bite)	Decoction	Oral
63	†Acorus calamus L. (Acoraceae)	Vasambu	1.80	Rhizome	RSD-5 (cough)	Decoction	Oral
64	∗,†Aerva lanata L. (Ameranthaceae)	Poolai poo	1.20	Leaf	ED-6 (kidney stone)	Raw	Oral
65	†Alpinia galanga L. (Zingiberaceae)	Perratthei	0.40	Rhizome	SMSD-1 (rheumatism) GIA-1 (ulcer)	DecoctionDecoction	OralOral
66	†Aloe vera L. (Liliaceae)	Sotru katrallai	0.80	Whole plant	GUA-4 (menstrual problem)	Raw and Decoction	Oral
67	Amorphophallus paeniifolius (Dennst.) Nicolson. (Araceae)	Kattukarunai	1.00	Rhizome	GH-2 (tonic) GIA-1 (carminative) GUA-1 (menstrual problem) DID- 1 (antiinflammatory)	RawDecoctionDecoctionDecoction	OralOralOralOral
68	†Andrographis paniculata L. (Acanthaceae)	Neelavembu	0.80	Whole plant	PB-4 (snake bite)	Decoction	Oral
69	∗,†Anisomeles malabarica (L.) R.BR. (Lamiaceae)	Peymiratti	0.20	Leaf	DID-1 (eczema)	Past	Topical
70	†Asystasia gangetica L. (Acanthaceae)	Mitikirai	0.40	Leaf	SMSD-1 (rheumatism) ED-1 (diabetic)	DecoctionRaw	OralOral
71	†Centella asiatica L. (Apiaceae)	Vallarai	0.60	Whole plant	CSCD-1 (memory power) GIA-2 (gas trouble and stomach ache)	RawDecoction	OralOral
72	†Chromolaena odorata L. (Astraceae)	Kamyunist Alai	0.20	Leaf	DID-1 (wound healing)	Past	Topical
73	†Cleome aspera L. (Cleomaceae)	Karumpoondu	0.20	Leaf	DID-1 (eczema)	Past	Topical
74	†C. monophylla L. (Cleomaceae)	Ellukku sakkalathi	0.40	Leaf	Fvr-1 (fever) SMSD-1 (inflammation)	DecoctionDecoction	OralOral
75	∗,†C. viscosa L. (Cleomaceae)	Naikadugu	0.80	Leaf	ENT-4 (ear ache)	Decoction	Oral
76	†Coleus aromaticus Benth. (Lamiaceae)	Karpooravalli	0.40	Leaf	RSD-2 (cough and cold)	Raw and Decoction	Oral
77	†Commelina benghalensis L. (Comllinaceae)	Kancatam	0.20	Whole plant	DID-1 (wound healing)	Past	Topical
78	†Curcuma aromatica Salisb. (Zingiberaceae)	Manjal	1.00	Rhizome	SMSD-1 (tumor) DID-4 (wound healing and antiinflammatory)	RawDecoction	OralOral
79	∗,†Curculio orchids Gaertn. (Hypoxidaceae)	Nilapanai	1.20	Rhizome	CSCD-4(heart problem) SMSD-1 (joint pain)	DecoctionDecoction	OralOral
80	†Cyanotis axillaris L. (Commelinaceae)	Vallukkai	0.40	Leaf	SMSD-1 (swelling) DID-1 (itching)	RawDecoction	OralOral
81	†Cymbopogon citratus STAPF. (Poaceae)	Elumichai pul	0.20	Root	GIA-1 (diarrhoea)	Decoction	Oral
82	†Cynodon dactylon L. (Cyperaceae)	Arugam pull	0.40	Whole plant	GIA-2 (indigestion and stomach ache)	Raw and Decoction	Oral
83	†Cyperus rotundus L. (Cyperaceae)	Korai kilangu	0.20	Rhizome	DID-1 (wound)	Past	Oral
84	†Desmodium gangeticum (L.) DC. (Fabaceae)	Orilai	0.40	Stem and root	Fvr-1 (fever) SMSD-1 (head ache)	DecoctionDecoction	OralOral
85	†Eclipta prostrata L. (Asteraceae)	Karisalankanni	1.00	Leaf	HC-5 (hair tonic)	Decoction	Oral
86	∗,†Eleusine coracana (L.) Gaertn. (Poaceae)	Kaelvaragu	0.20	Seed	Fvr-1 (fever)	Decoction	Oral
87	†Enicostemma axillare L. (Gentianaceae)	Vellarugu	0.20	Leaf	PB-1 (snake bite)	Decoction	Oral
88	†E. littorale Blume. (Gentianaceae)	Vellarugu	1.20	Leaf	PB-6 (snake bite)	Decoction	Oral
89	†Evolvulus alsiniodes L. (Convolvulaceae)	Vishnukiranthi	0.20	Whole plant	Fvr-1 (fever)	Decoction	Oral
90	†Hemidesmus indicus L. (Asclipadaceae)	Nannari	0.80	Root	Fvr-1 (fever) GIA-3 (stomach problem)	DecoctionDecoction	OralOral
91	∗,†Hybanthus enneaspermus L. (Violaceae)	Orithalthamarai	1.00	Whole plant	GUA-5 (male fertility)	Raw and Decoction	Oral
92	†Hygrophylla auriculata Schum. (Acanthaceae)	Voyal chullai	0.20	Leaf	GUA-1 (menstrual problem)	Decoction	Oral
93	†Hyptis sauveolens (L.) Poit. (Lamiaceae)	Karunchsatachi	0.20	Leaf	DID-1 (eczema)	Past	Topical
94	†Leonotis nepetaefolia (L.) W.T. Ait. (Fabaceae)	Theanthumpai	0.20	Leaf	DID-1 (eczema)	Past	Topical
95	†Mimosa pudica L. (Fabaceae)	Thootal sinigi	1.20	Whole plant	CA-4 (body coolant) RSD-2 (asthma)	DecoctionDecoction	OralOral
96	†Notonia grandiflora DC. (Astraceae)	Muyalkathu	0.20	Leaf	ENT-1 (ear ache)	Decoction	Oral
97	†Ocimum sanctum L. (Lamiaceae)	Nallathulasi	1.20	Leaf	RSD-6 (cold and cough)	Decoction	Oral
98	†O. tenuiflorum L. (Lamiaceae)	Karut tulasi	0.40	Leaf	RSD-2 (cold and cough)	Decoction	Oral
99	†Oxalis corniculata L. (Oxalidaceae)	Paliakirai	0.40	Whole plant	Fvr-1 (fever) ED-1 (kidney stone)	DecoctionRaw	OralOral
100	†Phyllanthus amarus Schum. & Thonn. (Euphorbiaceae)	Kizhaanelli	1.20	Whole plant	LP-6 (jaundice)	Decoction	Oral
101	†P. maderaspatensis L. (Euphorbiaceae)	Civappu kilanelli	0.60	Fruit	GIA-3 (indigestion)	Raw and Decoction	Oral
102	†P. reticulatus Poir. (Euphorbiaceae)	Karunelli	0.40	Leaf	GH-1 (piles) DID-1 (antioxidant)	DecoctionRaw	OralOral
103	∗,†Physalis minima L. (Solanaceae)	Kupanti	0.40	Leaf	GIA-1 (gas trouble)	Decoction	Oral
104	†Plectranthus amboinicus (Lour.) Spreng. (Lamiaceae)	Karpooravalli	1.20	Leaf	RSD-6 (cold and cough)	Decoction	Oral
105	†Plumbago zeylanica L. (Plumbaginaceae)	Chittiramoolam	1.20	Flower	GUA-5 (sterility in women)	Decoction	Oral
106	†Polygala arvensis Willd. (Polygalaceae)	Vecinankai	0.20	Root	SMSD-1 (inflammation)	Decoction	Oral
107	Pseudarthria viscida (L.) Wight & Arn. (Fabaceaae)	Moovilai	0.60	Stem and root	CSCD-1 (heart problem) Fvr-1 (fever) GIA-1 (dysentery)	DecoctionDecoctionDecoction	OralOralOral
108	†Sansevieria roxburghiana Schult. (Agavaceae)	Sanam	0.80	Leaf	ENT-4 (ear ache)	Decoction	Oral
109	†Sesamum indicum L. (Pedaliaceae)	Ellu	0.80	Seed	CA-4 (body coolant)	Decoction	Oral
110	∗,†Sida rhombifolia L. (Malvaceae)	Kurunthotti	0.40	Leaf and root	SMSD-1 (tumor) GIA-1 (gas trouble)	RawDecoction	OralOral
111	†Spermacoce latifolia Aubl. (Rubiaceae)	-	0.20	Leaf	DID-1 (wound healing)	Past	Topical
112	†Tephrosia purpurea (Linn.) Pers. (Fabaceae)	Kozhunji	0.20	Root	GIA-1 (stomach problem)	Decoction	Oral
113	∗,†Tragia involucrata L. (Euphorbiaceae)	Kanchori	0.20	Fruit	SMSD-1 (one side headache)	Raw and Decoction	Oral
114	†Tridax procumbens L. (Astraceae)	Vettukkaya puntu	0.80	Leaf	DID-4 (wound healing)	Past	Topical
115	†Vernonia cinerea (L.) Less. (Asteraceae)	Mukuttipoondu	0.20	Leaf	SMSD-1 (paralysis)	Decoction	Oral
116	†Vigna radiata (L.) R. Wilczek. (Fabaceae)	Pasipayaru	0.20	Seed and latex	DID-1 (skin disease)	Past	Topical
117	†Withania somnifera L. (Solanaceae)	Amukkaramkizangu	0.60	Rhizome	SMSD-3 (nervous disorders)	Decoction	Oral
118	Climbers†Abrus precatorius L. (Fabaceae)	Kundu mani	1.20	Seed, latex and root	ENT-4 (eye pain) GUA-2 (delivery pain)	DecoctionDecoction	OralOral
119	†Acacia sinuata (Lour.) Merr. (Fabaceae)	Seeyakkai	0.40	Fruit	DC-1 (toothache) HC-1 (dandruff)	PowderPowder	OralOral
120	†Ampelocissus tomentosa (Roth) Planch. (Vitaceae)	Kattukodi mundiri	0.80	Fruit	DID-4 (antioxidant and skin diseases)	Raw	Oral
121	†Asparagus racemosus Willd. (Asparagaceae)	Thanneervittan	1.20	Rhizome	ED-6 (urinary problem)	Decoction	Oral
122	†Antigonon leptopus Hook. & Arn. (Polygonaceae)	Kodi roja	0.20	Root	DID-1 (anti-inflammatory)	Decoction	Oral
123	†Aristolochia bracteolata L. (Aristolochiaceae)	Aaduthinnapalai	0.80	Leaf	DID-3 (eczema, scabies and ringworm infection) PB-1 (snake bite)	DecoctionDecoction	OralOral
124	†A. indica L. (Aristolochiaceae)	Aaduthinnapalai	0.80	Leaf	DID-3 (eczema, scabies and ringworm infection) PB-1 (snake bite)	DecoctionDecoction	OralOral
125	†Basella rubra L. (Basellaceae)	Kodippasali	0.40	Leaf	CSCD-2 (anaemia and increase WBC)	Raw and Decoction	Oral
126	†Cardiospermum canasense Wall. (Sapindaceae)	Mudakathan	1.40	Leaf	SMSD-6 (joint pain) GIA-1 (stomach ache)	RawDecoction	OralOral
127	∗,†C. halicacabum Wall. (Sapindaceae)	Mudakathan	1.00	Leaf	SMSD-4 (joint pain) GIA-1 (stomach ache)	RawDecoction	OralOral
128	†Cissus quadrangularis L. (Vitaceae)	Pirandai	1.00	Stem	GIA-5 (indigestion and inducing appetite)	Raw	Oral
129	†Coccinia grandis L. (Cucurbitaceae)	Kovai	0.20	Leaf	LP-1 (jaundice)	Decoction	Oral
130	†Cucurbita moschata Duch. ex Lam. (Cucurbitaceae)	Poosani	0.20	Fruit	GH-1 (increase weight)	Raw and Decoction	Oral
131	†Cuscuta chinensis L. (Convolvulaceae)	Manjapulluruvi	0.20	Stem	SMSD-1 (bone fracture)	Past	Oral
132	∗,†Cyclea peltata L. (Menispermaceae)	Padaikilangu	0.40	Whole plant	GIA-1 (stomach ache) GH-1 (tonic)	DecoctionDecoction	OralOral
133	†Dioscorea oppositifolia L. (Dioscoreaceae)	Kavvala kodi	1.60	Rhizome	GIA-4 (piles) DID-4 (wound)	DecoctionDecoction	OralOral
134	†D. pentaphylla L. (Dioscoreaceae)	Kaattuvalli	0.20	Rhizome	GIA-1 (stomach ache)	Decoction	Oral
135	†Gloriosa superba L. (Liliaceae)	Kanuvalikodi	0.20	Root	GUA-1 (abortion)	Decoction	Oral
136	†Gymnema sylvestre R. Br. (Asclipadaceae)	Chirukurunjan	1.00	Leaf	ED-5 (diabetes)	Decoction	Oral
137	†Ipomea staphylina Roemer & Schultes. (Convolvulaceae)	Onan kodi	0.20	Latex	GH-1 (cracked feet)	Raw	Oral
138	∗,†Mukia maderaspatana (Linn.) M. Roemer. (Cucurbitaceae)	Mosumosukkai	1.40	Leaf	GH-7 (piles)	Decoction	Oral
139	†Pergularia daemia Forsk. (Asclepiadaceae)	Vaeliparuththi	0.40	Leaf and fruit	RSD-1 (asthma) GIA-1 (gas trouble)	DecoctionDecoction	OralOral
140	†Piper betle L. (Piperaceae)	Vetrilai	1.20	Leaf	GIA-4 (indigestion) DID-2 (skin disease)	DecoctionPast	OralTopical
141	†P. nigrum L. (Piperaceae)	Kurumilagu	0.40	Seed	RSD-2 (cold and cough)	Decoction	Oral
142	†Sarcostemma acidum Roxb. (Asclepiadaceae)	Somamum	0.40	Latex	RSD-1 (cough) DID-1 (antiinflammatory)	DecoctionDecoction	OralOral
143	∗,†Solena amplexicaulis L. (Curcurbitaceae)	Pulivanchi	1.40	Rhizome	DID-7 (skin diseases and antiinflammatory)	Decoction	Oral
144	†Tylophora indica R. Br. (Asclipedaceae)	Mekachettu	0.20	Leaf	RSD-1 (asthma)	Decoction	Oral
145	Epiphytes†Loranthus flacata Linn. f. (Loranthaceae)	Pulluruvi	0.20	Bark	GUA-1 (menstrual problem)	Decoction	Oral
146	†Viscum album Mistletoe. (Loranthaceae)	Pulluruvi	0.80	Fruit	CSCD-3 (heart problem) SMSD-1 (tumour)	DecoctionDecoction	OralOral

∗Species of new claim; #Ailment categories: Circulatory system/cardiovascular diseases (CSCD), Cooling agent (CA), Dental care (DC), Dermatological infections/diseases (DID), Ear, nose, throat problems (ENT), Endocrinal disorders (ED), Fever (Fvr), Gastro-intestinal ailments (GIA), General health (GH), Genito-urinary ailments (GUA), Hair care (HC), Liver problem (LP), Poisonous bite (PB), Respiratory system diseases (RSD), Skeleto-muscular system disorders (SMSD) and Insecticidal (IC); †species with 100% fidelity level.

Figure 2

Percent life-forms of medicinal plants used by Irulas in Walayar valley.

Figure 3

Percent plant parts used for medicine preparation. Le – Leaf, St – Stem, Ba – Bark, Fl – Flower, Fr – Fruit, Se – Seed, La – Latex, Ro – Root, Rh – Rhizome, Wh - Whole plant and Mul - Multiple parts.

Table 2

Ingredients added for the preparation of herbal medicines by the Irula healers.

S. No.	Botanical name	Other plants added	Other ingredients added
1	TreesAcacia catechu	Alpinia galanga, Cleome monophylla and Cyanotis axillaris (chest pain)	Milk
2	A. leucophloea	Alangium salviifolium, Cyclea peltata, Dioscorea pentaphylla and Tephrosia purpurea (wound healing and stomach ache)	Coconut oil and honey
3	A. nilotica	Curcuma aromatica (toothache)	Coconut oil
4	Aegle marmelos	Curcuma aromatica, Piper nigrum and P. betle (diabetes)	Coconut oil and honey
5	Ailanthus excelsa	Curcuma aromatica, Piper nigrum and P. betle (menstrual problem)	Coconut oil
6	Alangium salviifolium	Acacia catechu, Terminalia arjuna, T. bellerica and Curculio orchids (chest pain)	Milk and honey
7	Albizia lebbeck	Anisomeles malabarica, Cleome aspera and Curcuma aromatica (eczema)	Coconut oil
8	Alstonia venenata	Curcuma aromatica (wound healing)	Coconut oil
9	Artocarpus heterophyllus	Ficus racemosa, Begonia malabarica, Pedalium murex and Cardiospermum halicacabum (arthritis and skin diseases)	Coconut oil
10	Azadirachta indica	Ficus racemosa, Alpinia galanga, Phyllanthus emblica and Asystasia gangetica (blood purification)	Milk and honey
11	Canarium strictum	Allium sativum and Curcuma aromatica (mosquito repellent)	–
12	Canthium diococcum	Curcuma aromatica, Piper nigrum and P. betle (dog bite and stomach ache)	Salt
13	Cassia fistula	Justicia adhatoda, Oxalis corniculata and Hemidesmus indicus (fever)	Milk
14	Cinnamomum camphora	Helicteres isora, Cleome viscosa and Costus specious (ear ache)	Coconut oil
15	Commiphora caudata	Ocimum sanctum, Cleome monophylla and Piper nigrum (fever)	Milk/honey
16	Dalbergia sissoo Roxb.	Curcuma aromatica (skin diseases)	Coconut oil
17	Dodonaea angustifolia	Cardiospermum halicacabum, C. canasense, Curculio orchids and Cissus quadrangularis (joint pain)	Egg white yoke and coconut oil
18	Erythrina variegata	Ocimum tenuiflorum, Piper nigrum and P. betle (cough and cold)	Honey
19	Ficus racemosa	Hemidesmus indicus, Pavetta indica, Vetiveria zizanioides, Curcuma aromatica and Ailanthus excelsa (leucorrhoea)	Milk and honey
20	Limonia acidissima	Hemidesmus indicus, Pavetta indica, Vetiveria zizanioides, Curcuma aromatica, Cardiospermum canasense and Ailanthus excelsa (leucorrhoea and arthritis)	Milk and honey
21	Mangifera indica	Curcuma aromatica (wound healing)	Coconut oil
22	Melia azedarach	Hemidesmus indicus, Terminalia arjuna, T. bellerica, Centella asiatica and Cynodon dactylon (stomach ache)	Milk
23	M. dubia	Allium sativum, Canarium strictum and Curcuma aromatica (mosquito repellent)	–
24	Mesua ferrea	Curcuma aromatica, Piper nigrum and P. betle (dog bite and stomach ache)	Sugar
25	Phyllanthus emblica	–	Sugar, milk and honey
26	Pongamia pinnata	Cardiospermum halicacabum and Cardiospermum canasense (rheumatism)	Neem oil
27	Syzygium cuminii	–	Milk and honey
28	Tamarindus indica	Curcuma aromatica, Piper nigrum and P. betle (scorpion bite)	Coconut oil
29	Terminalia arjuna	Alpinia galanga, Curculio orchids, Cleome monophylla, Terminalia bellerica and Cyanotis axillaris (chest pain)	Coconut oil, sugar and honey
30	T. bellerica	Alpinia galanga, Curculio orchids, Cleome monophylla, Terminalia bellerica and Cyanotis axillaris (chest pain)	Coconut oil, sugar and honey
31	T. chebula	Curcuma aromatica, Piper nigrum and P. betle (dog bite and stomach ache)	Salt
32	Wrightia tinctoria	Curcuma aromatica (toothache)	–
33	Ziziphus mauritiana	Curcuma aromatica (wound healing)	Coconut oil
34	Z. enophylla	Curcuma aromatica (wound healing)	Coconut oil
35	ShrubsArgemone mexicana	Curcuma aromatica, Piper nigrum and P. betle (ulcer and pimples)	Milk and coconut oil
36	Atalantia monophylla	Adhatoda vasica, Eucalyptus globules and Ocimum basilicum (body pain)	Honey
37	Begonia malabarica	Cardiospermum halicacabum, C. canasense and Cissus quadrangularis (arthritis and joint pain)	Egg white yoke
38	Cassia auriculata	–	Milk
39	Citrus limon	–	Salt and sugar
40	Clerodendrum inerme	Curcuma aromatica (skin diseases)	Coconut oil
41	Helicteres isora	Cleome viscosa and Costus specious (ear ache)	Coconut oil
42	Jatropha gossypifolia	–	Coconut oil
43	Justicia adhatoda	Syzygium cuminii, Ocimum sanctum, Begonia malabarica, Piper nigrum and P. betle (fever)	–
44	J. gendarussa	–	Coconut oil
45	Lantana camara	Curcuma aromatica (wound healing)	Coconut oil
46	L. wightii	Curcuma aromatica (wound healing)	Coconut oil
47	Manihot esculenta	Curcuma aromatica (wound healing)	Coconut oil
48	Pavetta indica	Achyranthes aspera, Enicostemma littorale, Rauvolfia serpentina, R. trtraphylla, Ocimum sanctum, Piper nigrum and P. betle (snake bite)	–
49	Rauvolfia serpentina	Achyranthes aspera, Enicostemma littorale, Ocimum sanctum, Rauvolfia trtraphylla, Piper nigrum and P. betle (snake bite)	–
50	R. trtraphylla	Achyranthes aspera, Enicostemma littorale, Rauvolfia serpentina, Ocimum sanctum, Piper nigrum and P. betle (snake bite)	–
51	Solanum surattense	Piper nigrum, Zingiber officinale and Asystasia gangetica (weezing)	Food
52	Vitex negundo	Cleome viscosa, Cynodon dactylon, Euphorbia hirta, Ocimum sanctum and Piper nigrum (headache and body pain)	Coconut oil
53	HerbsAbutilon indicum	Cassia auriculata and Cynodon dactylon (piles)	Castor oil
54	Acalypha indica	Piper nigrum and P. betle (jaundice)	Milk
55	Achyranthes aspera	Citrus limon, Vitex negundo, Piper nigrum and P. betle (dog bite and poisonous bite)	–
56	Acorus calamus	Ocimum sanctum, Piper nigrum and P. betle (cough)	Honey
57	Curculio orchids	Citrus limon, Pseudarthria viscid, Terminalia arjuna and T. bellerica (heart problem) Cardiospermum halicacabum and C. canasense (joint pain)	–Egg white yoke
58	Cleome monophylla	Commiphora caudate, Ocimum sanctum and Piper nigrum (fever)	Milk/honey
59	C. viscosa	Cinnamomum camphora, Helicteres isora and Costus specious (ear ache)	Coconut oil
60	Coleus aromaticus	Piper nigrum and P. betle (cough and cold)	–
61	Cymbopogon citratus	Allium sativum and Piper nigrum (diarrhoea)	Sugar/salt
62	Cynodon dactylon	–	Sugar
63	Desmodium gangeticum	Curcuma aromatica, Piper nigrum, Hemidesmus indicus and Ocimum sanctum (fever) Cleome viscose and Cynodon dactylon (headache)	Gingelly oil and Neem oil
64	Eclipta prostrata	Phyllanthus emblica, Hibiscus rosa-siensis, Cleome viscose and Cynodon dactylon (hair tonic)	Coconut oil
65	Eleusine coracana	–	Salt
66	Enicostemma axillare	Achyranthes aspera, Enicostemma littorale, Rauvolfia trtraphylla, Hibiscus rosa-siensis, Ocimum sanctum, Piper nigrum and P. betle (snake bite)	Salt
67	E. littorale	Achyranthes aspera, Enicostemma axillare, Rauvolfia trtraphylla, Hibiscus rosa-siensis, Ocimum sanctum, Piper nigrum and P. betle (snake bite)	Salt
68	Evolvulus alsiniodes	–	Sugar
69	Hemidesmus indicus	Ocimum sanctum and Piper nigrum (fever)
70	Hybanthus enneaspermus	–	Milk and honey
71	Hygrophylla auriculata	–	Honey
72	Mimosa pudica	Alpinia galanga, Piper nigrum and Zingiber officinale (asthma)	Honey
73	Notonia grandiflora	Helicteres isora, Cleome viscosa and Costus specious (ear ache)	Coconut oil
74	Ocimum sanctum	Piper nigrum and P. betle (cough and cold)	Honey
75	O. tenuiflorum	Piper nigrum and P. betle (cough and cold)	Honey
76	Oxalis corniculata	Hemidesmus indicus, Piper nigrum and P. betle (fever)	Honey
77	Phyllanthus amarus	Andrographis paniculata, Piper nigrum and Piper betle (jaundice)	Milk
78	P. reticulatus	Abutilon indicum, Cassia auriculata and Cynodon dactylon (piles)	–
79	Physalis minima	Piper nigrum and P. betle (gas trouble)	Milk
80	Plectranthus amboinicus	Piper nigrum and P. betle (cough and cold)	Honey
81	Plumbago zeylanica	Hemidesmus indicus, Pavetta indica, Vetiveria zizanioides, Hybanthus enneaspermus, Begonia malabarica and Piper nigrum (sterility in women)	Milk/honey
82	Pseudarthria viscida	Terminalia arjuna, T. bellerica, T. chebula, Curculio orchids, Phyllanthus emblica and Desmodium gangeticum (heart problem and fever)	Coconut oil, Milk/honey
83	Sansevieria roxburghiana	Helicteres isora, Cleome viscosa and Costus specious (ear ache)	Coconut oil
84	Sida rhombifolia	Curcuma aromatica, C. neilgherrensis, Piper nigrum, Zingiber officinale, Wrightia tinctoria and Asparagus racemosus (tumor)	Coconut oil, salt, milk/honey
85	Spermacoce latifolia	Commelina benghalensis and Curcuma aromatica (wound healing)	Coconut oil
86	Tephrosia purpurea	Hemidesmus indicus, Cymbopogon citratus and Zingiber officinale (stomach problem)	Milk/honey
87	Tridax procumbens	Curcuma aromatica (wound healing)	Coconut oil
88	Vernonia cinerea	Curcuma aromatica, Cardiospermum halicacabum and C. canasense (paralysis)	Egg white yoke
89	Vigna radiata	Curcuma aromatica (skin disease)	Coconut oil
90	Withania somnifera	Syzygium cuminii, Begonia malabarica, Piper nigrum and P. betle (fever)	Milk/honey
91	ClimbersAbrus precatorius	Asparagus racemosus, Acalypha indica, Citrus limon, Curcuma aromatica, Piper nigrum, Allium sativum, Cleome viscosa and Costus specious (delivery pain and eye pain)	Milk/honey
92	Ampelocissus tomentosa	Curcuma aromatica and Citrus limon (antioxidant and skin diseases)	Honey and coconut oil
93	Antigonon leptopus	Curcuma aromatica, Solena amplexicaulis and Citrus limon (anti-inflammatory)	Coconut oil
94	Asparagus racemosus	Allium sativum, Citrus limon, Cyperus rotundus and Phyllanthus amarus (urinary problem)	Butter milk/cow milk
95	Aristolochia bracteolata	Achyranthes aspera, Aristolochia indica, Curcuma aromatica, Zingiber officinale, Wrightia tinctoria, Citrus limon, Vitex negundo, Piper nigrum and P. betle (snake bite, eczema, scabies and ringworm infection)	Coconut oil
96	Basella rubra	Basella alba, Phyllanthus emblica, Centella asiatica and Ficus racemosa (anaemia and increase WBC)	Honey
97	Cardiospermum canasense	Cardiospermum halicacabum, C. canasense, Curculio orchids, Cissus quadrangularis and Dodonaea angustifolia (joint pain)	Pungam oil, egg white yoke and coconut oil
98	Cissus quadrangularis	Allium cepa, A. sativum and Murraya koenigii (indigestion and inducing appetite)	Asafoetida
99	Coccinia grandis	Azadirachta indica, Phyllanthus amarus, Ocimum sanctum, Piper nigrum and P. betle (jaundice)	Milk and honey
100	Cucurbita moschata	Allium cepa, A. sativum and Murraya koenigii (increase weight)	Gingelly oil
101	Cuscuta chinensis	Cardiospermum halicacabum, Cissus quadrangularis and Curculio orchids (joint pain)	Egg white yoke and coconut oil
102	Cyclea peltata	Hemidesmus indicus, Pavetta indica and Vetiveria zizanioides (stomach ache and tonic)	Milk
103	Dioscorea oppositifolia	Abutilon indicum, Cassia auriculata and Cynodon dactylon (piles)	Castor oil
104	D. pentaphylla	Hemidesmus indicus, Allium cepa and A. sativum (stomach ache)	Milk and honey
105	Gloriosa superba	Cynodon dactylon, Justicia adhatoda, Piper nigrum and P. betle (abortion)	Coconut oil and honey
106	Gymnema sylvestre	–	Milk and honey
107	Ipomea staphylina	Curcuma aromatica, Cocculus hirsutus, Cuminum cyminum and Madhuca longifolia (cracked feet)	Coconut oil
108	Mukia maderaspatana	Curcuma aromatica (piles)	Coconut oil
109	Pergularia daemia	Piper nigrum and Tephrosia purpurea (asthma and gas trouble)	Milk
110	Piper betle	Coccinia grandis, Cissus quadrangularis, Curcuma aromatica and Piper nigrum (indigestion and skin diseases)	Milk and honey
111	P. nigrum	Allium cepa, A. sativum, Piper nigrum and P. betle (cold and cough)	Milk and honey
112	Sarcostemma acidum	Cocculus hirsutus, Cuminum cyminum and Madhuca longifolia (cough and antiinflammatory)	Coconut oil
113	Solena amplexicaulis	Cuminum cyminum and Madhuca longifolia (antiinflammatory)	Coconut oil
114	Tylophora indica	Piper nigrum, Withania somnifera, Allium sativum and Tephrosia purpurea (asthma and gas trouble)	Milk
115	EpiphytesLoranthus flacata	Curcuma aromatica, Piper nigrum and P. betle (menstrual problem)	Coconut oil
116	Viscum album	Acacia catechu, Terminalia arjuna, T. bellerica and Curculio orchids (chest pain)	Milk and honey

Figure 4

Percent form of medicine preparation by Irula tribe.

Evidently, the current study documents, Acorus calamus as the most commonly used species prescribed for the treatment of cough by the Irula tribes with highest use value of 1.80 (Table 1). Other important species with high use value more than 1.20 were Abrus precatorius, Acacia leucophloea, Aerva lanata, Albizia amara, Cardiospermum canescens, Cassia auriculata, Dioscorea oppositifolia, Enicostemma littorale, Justicia adhatoda, Mimosa pudica, Mukia maderaspatana, Ocimum sanctum, Phyllanthus amarus, Piper betle, Plectranthus amboinicus, Plumbago zeylanica, Solanum surattense, Solena amplexicaulis, Syzygium cumini and Vitex negundo (Table 1). For employing informant consensus factor (F), more than 50 use-reports were obtained for certain ailment categories viz., dermatological infections (82 use-reports, 45 species), skeleto-muscular system disorders (54 use-reports, 29 species) and gastro-intestinal ailments (50 use-reports, 30 species) (Table 3) and their F values ranged between 0.10 and 1.0 (Table 3). In this study, high F value was obtained for insecticidal uses (1.0) and cooling agent (0.85), whereas lower F was obtained for endocrinal disorders, especially diabetes (0.10). It was found that the Irula tribals commonly apply bark powders of Canarium strictum and Melia dubia for mosquito repellency and Mimosa pudica and Sesamum indicum as body coolant in Walayar valley. Appreciably, it has been determined that a high number of 100 species have obtained 100% fidelity and were highly preferred for treating particular ailments (Table 1).

Table 3

Ethnobotanical consensus index for traditional medicinal plant use categories.

S. No.	Ailment category	Number of use-reports (Nur)	Number of taxa (Nt)	Informants’ consensus factor (Fic)
1.	Circulatory system/cardiovascular diseases (CSCD)	14	8	0.46
2.	Cooling agent (CA)	8	2	0.85
3.	Dental care (DC)	6	4	0.40
4.	Dermatological infections/diseases (DID)	82	45	0.45
5.	Ear, nose, throat problems (ENT)	19	8	0.61
6.	Endocrinal disorders (ED)	31	28	0.10
7.	Fever (Fvr)	20	11	0.47
8.	Gastro-intestinal ailments (GIA)	50	30	0.40
9.	General health (GH)	23	9	0.63
10.	Genito-urinary ailments (GUA)	25	12	0.54
11.	Hair care (HC)	8	4	0.57
12.	Liver problem (LP)	8	3	0.71
13.	Poisonous bite (PB)	29	12	0.60
14.	Respiratory system diseases (RSD)	35	16	0.55
15.	Skeleto-muscular system disorders (SMSD)	54	29	0.47
16.	Insecticidal (IC)	2	2	1.00
Total		414	223
				Average Fic = 0.55

Discussion

The information on therapeutic uses of 146 species (Table 1) collected from the Irula tribal community of Walayar valley was compared with that of the early publications (Rajendran and Henry, 1994, Vashistha, 2015). In this content, 26 new claims were documented and are reported for the first time in this study (Table 1). Remaining species were already reported for their various medicinal uses (Jain and Goel, 1995, Yesodharana and Sujana, 2007, Sanjeev et al., 2015). Among the 58 families represented, Fabaceae manifested the first dominant family in terms of species richness followed by Euphorbiaceae, Lamiaceae and Asclepiadaceae (Table 1). It has been reported already that the members of these families, owing to rich variety of secondary metabolites and Lamiaceae members due to more types of volatile oils are getting importance in healing the illness (Sanjeev et al., 2015). From the life-form analysis, herbs were found to be the most common functional group of plants followed by trees and climbers (Fig. 2). In general, richness of herbaceous species than any other life-forms is higher in any natural community which may lead to more use of herbs for medicinal purposes than the species of other habits (Giday et al., 2010, Pushpakarani and Natarajan, 2014, Swapna, 2015). In support of this fact, Venkatachalapathi et al. (2014), also enumerated a higher number of herbaceous species than the other life-forms in various vegetations of Attukal area of Western Ghats, an adjoining part of Walayar valley.

Among the assortment of plant parts utilized, leaves were most frequently used by the Irula tribal community for healing purpose (Fig. 3). These results were in accordance with previous literatures that several traditional healers prescribe mainly the leaves for the preparation of medicines (Gonzalez et al., 2010, Amjad et al., 2015). Umapriya et al. (2011) found that the Irula tribals of Palamalai hills of Coimbatore, India also utilize leaves mainly for their therapeutic applications. Perhaps a more likely explanation for the high utility of leaves is that they can be collected very easily than the other parts (Ayyanar and Ignacimuthu, 2011). Furthermore, leaves are the active sites of photosynthesis and hence the production of a variety of bioactive entities (Bahmani et al., 2014). Obviously, for remedies preparations decoction form was prescribed by Irulas in Walayar valley (Fig. 4). Decoction is the major form of medicine preparation in some tribal communities worldwide (Ahirwar, 2010, Bahmani et al., 2014, Amjad et al., 2015). Raw consumption, paste and powder forms were also prepared and prescribed by the Irulas of Walayar. Further, Irula healers informed that preparation of medicine was made by using single plant part or in combination with parts of more than one species (Table 2). The study revealed that a single mode of medicine preparation was more predominant (52.7%) in comparison to multiple modes (26.01%). Umapriya et al. (2011) also reported that the single mode of medicine preparation by the Irula tribe in Palamalai hills of Western Ghats, is the most common type. Similar observations for other tribal communities were documented elsewhere (Erinoso and Aworinde, 2012, Savithramma et al., 2012, Senthilkumar et al., 2013, Shosan et al., 2014). The single mode of medicine preparation by the Irula tribe may be attributed to the presence of phytochemical constituents such as saponins, tannins, alkaloids, alkenyl phenols, flavonoids, terpenoids, phorbol esters and sesquiterpene lactones in the individual herbals which lead to the desired healing effect (Lixin et al., 2014). A single herb may even contain more than one aforementioned phytochemical constituents which works synergistically with each other in producing pharmacological effect (Bahmani et al., 2015). A sizeable number of 38 species used for multiple modes of preparation of medicine in the present study may be explained that certain pharmacological actions of active constituents of certain herbals are significant only when potentiated with other plants, but not evident when used alone (Parasuraman et al., 2014). Similar to Kani tribe (Ayyanar and Ignacimuthu, 2011), Irula tribal healers of Walayar valley utilize oils of coconut, castor, gingelly, pongam and neem for the preparation of paste. According to their traditional knowledge, certain specific plant parts were used for the preparation of medicines and they were administrated in dosage according to the age of the patients. The present study clearly demonstrated that some plants have high use value (Table 1). Among them, Acorus calamus is the most specifically used species well recognized by all informants for the treatment of cough. Similar to our study, Arunachalam and Parimelazhagan (2011) also reported that this species is generally prescribed by the Hooralis tribes of Kadambur hills of Eastern Ghats, India for treating cough and other throat problems. Saikia et al. (2013) in Assam and Venkatachalapathi et al. (2015) in nearby Walayar valley also found that A. calamus is mainly prescribed for the treatment of cough. In contrast, certain plant species were reported to have very low use values (0.20) in the present study as they were used for very little number of specific uses (Table 1).

Informant consensus factor (F)

F arrived for any species depends upon its availability and the knowledge of informants on medicinal plants (Venkatachalapathi et al., 2015). In the present study, the illnesses were grouped into 16 major ailment categories and their F values ranged between 0.10 and 1.0 per illness category (Table 3). The average F value for all ailment categories was 0.55, indicating a moderate level of informant consensus. However, it was not comparable to that of other studies in Tamilnadu by Ragupathy et al. (2008) among the “Malasars” of Velliangiri holy hills and Ayyanar and Ignacimuthu (2011) among the Kani tribals in Tirunelveli hills, the only two investigations with quantitative assessment in Tamil Nadu that showed the average F values, more than 0.70. Remarkably, high F obtained in the present study for the two ailment categories viz., insecticidal uses (1.0) and cooling agent (0.85), indicating a higher level of consensus among the Irula healers for the usage of species for these categories. They commonly apply bark powder of the species, Canarium strictum and Melia dubia particularly in avoiding mosquito bites through topical application. The insecticidal property category was not included in standardized illness groupings by Cook (1995). However, it was included in the present study, as the Irula tribes were commonly using these two species for their mosquito repellency very regularly. It may be explained that as the Walayar valley is situated in Palakkad gap of Western Ghats, rainfall through south-west monsoon is highly effective (ca. 1100 mm between June and September alone). This moist condition results in thick vegetations of various types and the wetted soil with dense plant formation becomes the favourable site for insects including mosquitos. Higher informant consensus was recorded by other workers also for certain ailment categories (Owuor and Kisangan, 2006, Black et al., 2007, Ragupathy et al., 2008, Ayyanar and Ignacimuthu, 2011, Venkatachalapathi et al., 2015). The high F obtained may indicate that there may be some key phytochemical ingredients in these species which require further phytopharmacological analysis to validate the species scientifically. In our study, lower consensus factor was obtained for endocrinal disorders (F 0.10) which includes only one illness, diabetes (Table 3). Logically, it may be the indicative of the lack of diabetic patients among the Irula communities of Walayar valley. However, no clinical data are made available for diabetics for the Irula tribals in Walayar area.

Fidelity level

Among the 146 plants used for medicinal purposes by the Irula tribal community, interestingly it has been determined that a high number of 100 species have obtained 100% fidelity and most of them were used for the treatment of single ailment category as per the informants (Table 1). This fact indicates that all these 100 species were the highly preferred plants for treating the illness of particular ailment category due to their high healing potential. In agreement with the present findings, the species viz., Acacia nilotica, Acorus calamus, Cassia auriculata, Cissus quadrangularis, Tridax procumbens and Vitex negundo available in Walayar landscape were already reported to have 100% fidelity in Tirunelveli hills (Ayyanar and Ignacimuthu, 2011).

Conclusion

This wide spectrum of usage of 146 plant species indicates their strong traditional knowledge on medicinal plants. The moderate, average F value (0.55) reveals that the consensus on traditional knowledge on medicinal plants among the Irula healers of this landscape has not been shared adequately. However, consensus for certain illness categories viz., insecticidal property and cooling agent shows the effectiveness and reliability of the species viz., Canarium strictum and Melia dubia, and Mimosa pudica and Sesamum indicum on healing the respective ailment. Several new claims made in the study showed the unique knowledge of Irulas of this region on medicinal plants. Recognizing more species with high fidelity level and greater use value indicates the presence of rich varieties of phytoconstituents in these species. The species of high use value, new claims and greater fidelity level and the taxa on which higher consensus were obtained among the informants for using them in particular ailment category are suggested for further studies in the line of phytochemistry and pharmacology and hence to identify them for pharma industries.