Ethnomedicinal uses of plants by Santal tribe of Alipurduar district, West Bengal, India

Objectives: To document the traditional knowledge on medicinal plants used by the Santal tribe residing at seven different villages in Alipurduar district of West Bengal, India to treat common human ailments. Methods: The field survey was conducted during July 2018 to January 2020 using guided fieldwalk method. Santal traditional medicinal practitioners (locally called Kabiraj) and local knowledgeable Santal men and women were interviewed with the help of pretested semi-structured questionnaries to record their knowledge on ethnomedicinal uses of local vegetation in their surroundings. The questionnaire covered aspects like local name, scientific name, family, used parts, ethnomedicinal uses, among others. Plants were collected mostly during the flowering stage and routinemethod of herbarium techniques was followed and the collected plants were identified using relevant sources. Findings: Altogether 73medicinal plants of 45 families were recorded to be used to treat 38 types of diseases ranging from very common physical problems to complex diseases. Fabaceae represents the highest number (5 species) of medicinal plants. Herbs (39.73%) and trees (38.36%) represents the dominant life-forms andmostly the plants were collected from the natural habitat (56.16%). For the preparation of medicine, leaves were found to be most frequently used (47.50%) plant part than the others. In general, ethnomedicines were prepared from the fresh plant materials and were administered orally (66.25%) or topically (33.75%). Applications: Documentation of medicinal plants used by the Santals in the treatment of various diseases could further be utilised to develop new drugs and pharmaceutical products. However, to achieve sustainable development, conservation, cultivation and proper utilisation of medicinal plants should be monitored scientifically. Novelty: Utilization of medicinal plants by the Santal tribe has been documented for the first time from Alipurduar district and has enriched the existing database of medicinal plants.


Introduction
India, the home of the World's largest number of indigenous people (8.6% of the total population of India) (1) has a rich herbal heritage. It is well known that the tribal people are mostly dependent on plants than the other communities for their daily livelihood, especially for herbal medicine. Even today, in developing countries, more than 80% population is directly dependent on herbal medicine for healthcare (2,3) . In India, the use of medicinal plants for the treatment of diverse variety of ailments has been recorded from ancient times (4,5) and the documentation of such traditional knowledge on ethnomedicine has developed many modern medicines (6,7) . Santals, one of the Adivasi, the third-largest tribes in India after Bhil and Gond, mainly found in the states like Jharkhand, West Bengal, Assam, Tripura, Bihar and Odisha. In West Bengal, they constitute 47.43% of the total tribal population, of which 94.02% lives in rural areas (Census India 2011; http://censusindia.gov.in/). The people from rural areas mostly depend on the herbal or traditional medicine in-spite of the development of modern medicine due to low cost of herbal medicine, unavailability of primary healthcare services and the side effect of the synthetic drugs (8) . Santals are the descendants of the Austric-speaking Proto-Australoid race (9) . As they have lived on this land probably for thousands of years, they are a rich depository and guardians of indigenous traditional knowledge on medicinal plants (10) and most of the knowledge passed on by verbal means from one generation to another and very rarely documented (11) . So, documentation of the medicinal plants used by them can play an important role in the conservation of indigenous knowledge as well as such documentation may be a potential source of discovery of newer and effective drugs. However, day-by-day the population to carry on traditional knowledge is reducing due to the impact of Western lifestyle (12) and less interest on the usefulness of medicinal plants are available in their surroundings (13) .
Several ethnobotanical studies on medicinal plants have been conducted in different districts of West Bengal over the past six decades  , focusing primarily on various ethnic groups, but documentation of the ethnobotanical knowledge of Santal tribe is very scanty (37)(38)(39) .
Scientific documentation of the traditional knowledge of Santal tribe in Alipurduar district of West Bengal is not made so far as per literature surveyed. Sukla and Chakravarty (40) and Raj et al. (41) Figure 1).

Data collection
A total of four field trips were completed for the documentation of traditional knowledge on medicinal plants during July 2018 to January 2020. The data were collected with the help of pretested semi-structured questionnaires (43) . Two Santal traditional healers and other knowledgeable persons were interviewed. Prior Informed Consent (PIC) was taken from each informant before interview. Information about the plants were recorded with regards to their vernacular/ Santal name(s), plant parts used, uses, process of preparation of medicine either individually or in combination with other plant parts, and mode of application and dosages for the treatment of a particular disease(s). Plant specimens were collected in their flowering condition as far as possible with guided-walk. Routine methods of plant collection and herbarium techniques (44) have been followed during the study. Digital photographs of the plants were also taken wherever possible. Plant specimens were identified with the help of relevant floras and standard literatures (45)(46)(47) and the voucher specimens were kept at the Department of Botany, A. B. N. Seal College, Cooch Behar.

Results and Discussion
The results of the field survey have been presented in Table 1. The collected medicinal plants are arranged in alphabetical order according to families and then according to genus and species within -each family. Information regarding Santal name(s) (as recorded during the field work), scientific name, family, habit, parts used and ethnomedicinal uses for each species have also been provided. In most cases, however, the precise method of the preparation of medicine and dosage of administration were not disclosed. As the tribal healers were afraid that on disclosure of such knowledge to the outsiders, their value as a medicine man gets affected.

Medicinal plants recorded and their distribution into families
The present field survey has recorded a total of 73 ethnomedicinal plants belonging to 69 genera and 45 families ( Table 1 ; Figure 2) used by the Santal tribal healers and other Santal men and women. Distribution of plants within families shows variation. The family Fabaceae is represented by highest number of species (5 species, 6.85 %) followed by Apocynaceae (4 species, 5.48 %), Acanthaceae, Amaranthaceae, Arecaceae, Cucurbitaceae, Moraceae, Piperaceae and Solanaceae (3 species each, 4.11 %), Amaryllidaceae, Asteraceae, Combretaceae, Lamiaceae, Poaceae, Rutaceae and Zingiberaceae (2 species each, 2.74 %) and the rest 29 families represented by single species (1.37 %). The members of the family Fabaceae contain active chemical constituents like flavonoids, alkaloids, coumarins, tannins, etc. (48) , which are used extensively in the treatment of wide variety of human diseases (49) .
Result on the growth habit of the plants shows that herb (29 species, 39.73%) and tree (28 species, 38.36%) dominates among the plant type followed by climber (9 species, 12.33%) and shrub (7 species, 9.59%). Mostly the plants were collected from natural habitat (56.16%) and the rest from the home gardens (43.84%). Besides, collection from natural vegetation, cultivation of medicinal plants in their home garden probably indicated their dependency on ethnomedicine to get relief from common physical problems.

Plant parts used, mode of preparation and routes of administration
For the preparation of medicine, various plant parts ( Table 1; Figure 3) are found to be used by the Santals. Leaves (47.50%) are found to be the dominant plant parts used followed by fruits (11.25%), bark (10.0 %), roots and seeds (6.25% each), latex (5.0%), bulb, stem, tuber  (30,36,37,41,42,(50)(51)(52)(53)(54) . Use of plant parts other than leaves may harm the mother plant (37,55) and in the present study maximum utilization of leaves indicates sustainable use of the biological resources by the Santals.

Diseases treated
Altogether 38 types of physical problems ( Figure 4) were found to be treated by the use of the documented medicinal plants. Most of the herbal preparations are found to be used by the Santals to treat dysentery (11 species, 15.07%), followed by abdominal pain and skin diseases (6 species, 8.22% each), stomach problems and female disorders (5 species, 6.85% each), cough and cold, diarrhoea and fever (4 species, 5.48% https://www.indjst.org/ each), anemia, bone fracture, cuts and wounds, diabetes, hypertension, snake bite (3 species, 4.11% each), among others. This clearly suggests the great extent of traditional knowledge possessed by the healers and the other tribal people to treat several diseases. This knowledge is passed down by verbal means from one generation to another. In the study area, the traditional knowledge is also taught to the interested younger ones (only Santals) by the elders in a 5-days custom (starts on Maha Panchami of Durga puja festival) called Dasaibonga. However, recent generations are less aware regarding the importance of the rich traditional knowledge on medicinal plants in their elders. This observation is corroborated with the previous studies as reported by Khatun and Rahman (12) and Uniyal et al. (13) .

Conclusion
Scientific documentation of traditional knowledge of Santal tribe from the district Alipurduar is done for the first time which will definitely enrich the database. Their knowledge on ethnomedicinal plants is no doubt very rich in the treatment of very common physical problems to complex diseases. This knowledge may be helpful for the development of modern drugs. Day-by-day due to various reasons the natural vegetation degradation is rampant, it will be helpful for further research. Cultivation and sustainable utilization of the threatened taxa is utmost necessity in order to maintain their population in nature.