Ethnomedicinal uses of plants by major ethnic groups of Hilly Districts in Nepal: A review

Plants are used as ethno-medicine by indigenous people living all around the world. In Nepal, plants are being used for healing diseases since a long period by various ethnic groups of rural areas due to difficulty in the availability of modern medicines. Many researchers have contributed to documentation of ethnomedicinal knowledge on plants in Nepal; however few studies have been carried out on hilly districts. Our study aims to review and compile all the published research documents on ethnomedicinal uses of plants by various ethnic groups of hilly districts in Nepal. Altogether 35 published documents till August 2020, accessed through Google Scholar and Research Gate were selected for our study. A total of 215 plant species from 93 families was found to be used for the treatment of 139 types of diseases by 10 ethnic groups of 13 hilly districts. Also, leaves were used for the treatment of maximum numbers of diseases (69). Plants from Fabaceae, Asteraceae, and Poaceae, etc. were used to treat major diseases like; diabetes, asthma, stomachache, fever, jaundice, etc. Traditional knowledge on medicinal uses of plants is needed to be explored and documented to preserve traditional medicinal knowledge as well as medicinal plants.


INTRODUCTION
Ethno-botany is defined as the science of interaction between people and plants [1] and deals with the study and documentation of indigenous knowledge of people on plants i.e. how plant resources are used by ethnic groups (people having their own common cultures, languages, and belief systems) [2]. Ethno-medicine deals with the study of traditional medical practices by different ethnic groups [3]. More than 20,000 species of higher plants are used for the traditional medicinal practices by indigenous people (native people) living around the world [4]. Indigenous people of developed and developing countries are using plants as a source of medicine [5,6,7].
There are 1950 species of medicinal plants being used in Nepal [8], out of which 143 species are listed as commercial medicinal plants [9]. In Nepal, the lower sub-tropical region (1000-1500 m) harbors a maximum number (679 species) of medicinal plants [10]. Traditional herbal medicines have been practiced by rural people in Nepal since a long time ago because they are easily available, having no side-effects and are cheaper than modern medicines [11,12]. The ethnic groups have the best knowledge on the uses of plants and also transferring it to their next-generation [11]. The methods of using plants to cure several diseases vary among ethnic groups and also among healers [13]. The ethnomedicinal knowledge is being recognized worldwide because it support on innovation and formulation of many modern medicines [11,14]. The discovery of new drugs can be obtained through the bio-visioning of indigenous medicinal plants [15]. It is important to document and explore indigenous knowledge on medicinal plants of different ethnic groups because the knowledge might get lost with the loss of knowledgeable persons, biodiversity loss, and socio-economic changes [16,17].
Many researchers have contributed on ethnomedicinal study of plants in Nepal. However, no review study has been done till now on ethnomedicinal uses of plant species by various ethnic groups of hilly districts in Nepal. Therefore, this study has attempted to review and compile all research articles on ethnomedicinal uses of plants by different ethnic groups of hilly districts in Nepal.

MATERIALS AND METHODS
The entire information was obtained from a review of several published sources including research notes and reports, academic papers, journals, and theses from 1988-2020. Google Scholar and Research gate were the primary databases for obtaining the whole data on ethnomedicinal uses of several Miya, et al. Tangbetons Kaski 60 64 [32] (Abbreviation for districts is used for researches carried out from more than one district.)

RESULTS
There are 126 ethnic groups in Nepal, out of which 59 are officially recognized as indigenous ethnic groups [18]. Brahmin, Chhetri, Gurung, Magar, Tamang, Thami, Newar, Rai, Limbu, etc. are major indigenous ethnic groups residing on the hilly region of Nepal [18]. Documents focusing on single ethnic groups are described in our results and discussion. Ethnomedicinal uses of plants by 10 ethnic groups of 13 hilly districts are described in this paper.
The ethnic groups, their inhabited districts from where researches were carried out, numbers of plants used as a medicine, and numbers of diseases or ailments treated are mentioned in (Table 1). Plants with their scientific name, Nepali name, family, parts used, diseases treated, and used by respective ethnic groups are given in (Table 2).

DISCUSSION
Altogether 215 species of plants were found to be used for the treatment of 139 types of diseases. Whole plant or its parts i.e. rhizome, stem, bark, twig, leaf, root, fruit, bulb, seed, latex, tuber, flower, and buds of plants were used for the treatment of single or multiple diseases. The plants' parts used and numbers of diseases treated are mentioned in (Figure 1). According to our              analysis, the leaf is used for the treatment of maximum numbers of diseases (69 diseases) and twig being used for minimum numbers of diseases (7 diseases).

CONCLUSIONS
Medicinal plants are major sources of crude drugs for healing diseases by various ethnic groups living near the forests of Nepal. A total of 215 Plant species from 93 families is used for the treatment of 139 types of diseases or ailments by 10 ethnic groups residing in 13 hilly districts of Nepal. The whole plant or its parts were used for medicinal purposes and leaf is found to be used for the treatment of maximum numbers of diseases.
Ethnomedicinal knowledge is the foundation for the invention of new medicines. Proper documentation of traditional knowledge on medicinal plants with their identification and cultivation should be done which helps to preserve traditional knowledge as well as medicinal plants. Highly valuable medicinal plants are needed to be grown commercially to reduce pressure on these species in wild habitats. Young generations should be encouraged and trained in traditional medicinal knowledge. Phytochemical and pharmacological researches are needed to be carried out for scientific validation of the medicinal properties of the plant species used by indigenous people.