Ethnomedicinal plants used by the ethnic people living in fringe villages of Rasikbil of Cooch Behar District , West Bengal, India

Objectives: The field study was undertaken at the adjoining villages of Rasikbil of Cooch Behar district, West Bengal, India to record the ethnomedicinal plants used by the Rava, Santal and Oraon people and to explore their traditional knowledge to treat common ailments. Methods: With the help of pretested semi-structured questionnaire, tribal men and women were interviewed on ethnomedicinal uses of local flora during July 2018 to January 2020. The questionnaire covered aspects like local name, scientific name, family, used parts, ethnomedicinal uses, among others. Routine methods of plant collection and herbarium techniques were followed and the collected species were identified using relevant sources. Findings: A total of 57 plant species of 34 families were found to be used to treat several diseases like cough and cold, diabetes, among others. In few cases, the plant parts were used in combination with other plant parts to prepare traditionalmedicine. The plant family Fabaceae represents the highest number (6 species) of ethnomedicinal plants among others. Among different plant parts used for the preparation of medicine, leaves were most frequently used (49.12%) for the treatment of diseases. Besides, fruits, seeds, roots, etc. were also found to be used as traditional medicine for the treatment of ailments among human beings. Applications: The traditional knowledge of ethnic people regarding the utilisation of ethnomedicinal plants may be used in the preparation of pharmaceutical products which could contribute towards availability of essential drugs at much reduced cost. In addition, populations of medicinal plants must bemonitored in order to conserve them and aid in planning sustainable utilisation.Novelty: In comparison to earlier reports, present study revealed 14 more plant species having immense ethnomedicinal values and frequently used by the tribal people in the area. In this regard, the study is significant to enrich the existing database.


Introduction
The World Health Organization defines traditional medicine (or folk medicine) as "the sum total of the knowledge, skills, and practices based on the theories, beliefs, and experiences indigenous to different cultures, whether explicable or not, used in the maintenance of health as well as in the prevention, diagnosis, improvement or treatment of physical and mental illness" (1) . In India, the folklore systems play a crucial role in meeting the health care needs of the rural community (2) . The most ancient records of ethnomedicinal uses of plant species are available in the form of Vedas, Samhitas and Epics like Ramayana and Mahabharata. Traditional knowledge of medicinal plant species is an important source of information for health care, throughout the world (3) . Nowadays, despite of the development of the modern medical facilities, the rural people depend on the traditional medicine due to low cost, unavailability of primary healthcare service and the side effect of the synthetic drugs (4) . Over 80 % of the World's population directly depends upon the plants for their health care (5) . Recently, the plant species are facing highest threat of extinction mainly due to loss of natural habitat or climate change, urbanization, encroachment of forest lands, etc. So, it is utmost important to conserve the flora from destruction. Conservation and sustainable uses of biological resources are important in the preservation of traditional knowledge (6) .
The district of Cooch Behar is in the under developing status and mostly the rural people depend on medicinal plants to treat common physical problems like smaller injuries, cough and cold and abdominal disorder. Although, documentation of medicinal plants have been done earlier in the district (7)(8)(9)(10)(11)(12)(13) , the present study will definitely enrich the database of medicinal plants by recording new medicinal plant species used by the ethnic people in the district not reported earlier from the district. Keeping all these in mind, the present field survey was undertaken to explore traditional ethnomedicinal knowledge of ethnic people living in fringe villages of Rasikbil of Cooch Behar district of West Bengal, India.

Study Area
The survey work was carried out at the adjoining tribal villages (Atia Mochar, Chengtimari, Madhurbhasa, Paglirkuthi and Takoamari) of Rasikbil (

Data Collection
The field survey was carried out during July 2018 to January 2020 to collect information on the medicinal uses of plants found in the studied area. A total of four field surveys were done across different seasons to get maximum information. Routine methods of plant collection and herbarium techniques (14) have been followed in the study. The plants were collected in its flowering stage as far as possible, from its natural habitat. Digital photographs of the plants were also taken wherever possible. While collecting information on ethnomedicinal plants, information has been gathered by interviewing the tribal men and women using pretested semi-structured questionnaires (15) . Prior Informed Consent (PIC) was taken from each informant before the interview.
Information about the plants were recorded with regards to their vernacular/ local names, plant parts used, uses, process of preparation of medicine either individually or in combination with other plant parts, and mode of application and doses for the treatment of a particular disease(s). All the collected plant specimens were identified using relevant floras and standard literatures (16)(17)(18) and the voucher specimens were deposited in the Department of Botany, A. B. N. Seal College, Cooch Behar.

Results and Discussion
Altogether 57 plant species belonging to34 families ( Table 1 ; Figure 1 ) were found to be used for medicinal purposes by the ethnic people of the studied area to treat several diseases ( Figure 2 ). A total of 32 diseases ranging from common stomach problem to jaundice were treated by the use of these medicinal plants. Mostly traditional medicine found to be used by the tribal people to treat cough and cold and to heal cuts and wounds followed by diabetes, skin problems, intestinal worms, stomach problems, jaundice and dysentery. Most of the traditional knowledge of medicinal plants seems to be confined to the elder people, while the modern generation have little interest about the importance of the medicinal resources available in their surroundings (19) . https://www.indjst.org/   The plants listed are in the alphabetical order according to families, followed by genus and species within each family. The reported plants are arranged according to their vernacular name(s) (as recorded during the field work), scientific name, family, parts used and ethnomedicinal uses. Although, the respondents revealed preliminary information regarding the methodology of herbal preparations; but in most cases, they usually hesitate to disclose their knowledge about the exact methodology of herbal preparation and dosage as they believe that upon disclosure of the knowledge (particularly to urban people) the effect of medicine will vanish.
Most of the plants reported in this study were collected from their natural habitat (68.42%) and the rest from the home gardens (31.58%). On the basis of their growth habit, herb (38.60 %) dominates among plant types followed by tree (33.33%), shrub (22.81 %) and sub-shrub (5.26 %).
The plant family Fabaceae is represented by the highest number of species (6 species; 10.53%), followed by Apocynaceae (5 species; 8.77%), Lamiaceae (4 species; 7.02%), Acanthaceae, Asteraceae and Combretaceae (3 species each; 5.26%), Euphorbiaceae, Malvaceae, Myrtaceae, Rutaceae and Zingiberaceae (2 species each; 3.51 %), and the rest of the families are represented by single plant species each ( Figure 1). Among different plant parts used ( Figure 3) for the preparation of medicine, leaves are found to be the most frequently (49.12 %) used plant parts followed by fruits (14.04 %), seeds and roots (8.77 % each), flower and petiole (5.26 % each), bark, stem and rhizome (3.51 % each) and only in one occasion, the use of entire plant, flower bud and branch (1.75 %) are also recorded. In few cases, the plant parts are used in combination with other plant parts to prepare the traditional medicine. Most of the ethnobotanical studies confirmed that leaves are the major portion of the plant used in the treatment of diseases (10)(11)(12)(13)(20)(21)(22)(23)(24)(25) . Scientific documentation of the plant species utilised for different ethnomedicinal purposes by the ethnic communities in the Cooch Behar district have been done earlier by several authors (7)(8)(9)(10)(11)(12)(13) but the present survey has reported additional 14 medicinal plant species which is definitely a new inclusion in the existing database.
Although, the use of medicinal plants among the ethnic people in the studied area to treat different diseases is certainly outnumbered by the modern medicine, still their dependency on surrounding plants to get relieved from day-to-day ailments is https://www.indjst.org/ undeniable. Recently many medicinal plant species used by them are disappearing from the natural vegetation due to loss of natural habitat, encroachment of forest lands, illegal cattle grazing, etc. Bhattacharya et al. (26) has recommended few management strategies for the betterment of socio-environmental structure. Proper training and awareness programme from appropriate authority on the importance of biodiversity resources as well as harmful effects of deforestation may protect the natural habitat from destruction (26) . Sustainable uses and cultivation of these medicinal plants may restore the natural vegetation in the studied area. The conservation and sustainable use of medicinal plants have been studied extensively (27)(28)(29) .

Conclusion
There seems to be an in-depth knowledge about the curative properties of many plants among the tribal population living at the adjoining villages of Rasikbil, and the list of taxa presented here is by no means exhaustive. During the course of the study, 57 plants are found to be used by ethnic people in the studied area. In spite of the development and spread of modern medicine in the studied areas, traditional medicine is of prime importance to address health problems. Traditional knowledge of medicinal plants and their uses by ethnic communities are useful for conservation of inherited traditional medicine as well as for drug development. However, modern generations are least interested for traditional medicine. This study may help in the utilisation of these plants as crude drugs or as raw material in the preparation of pharmaceutical products required in the promotion of primary health care. This could contribute towards the availability of essential drugs at much reduced cost. However, it would only be possible if populations of medicinal plants are monitored scientifically in order to plan the proper conservation and sustainable utilisation.