Ethnomedicinal plant use by Lepcha tribe of Dzongu valley, bordering Khangchendzonga Biosphere Reserve, in North Sikkim, India

Lepcha is the oldest and the first tribe reported from Sikkim, India; majority of its population inhabiting in Dzongu valley, an officially demarcated reserve for Lepcha community, bordering Khangchendzonga Biosphere Reserve, in north district. Lepchas of Dzongu are known for their retention of rich cultural heritage. In view of the on-going cultural and economic changes brought in by the process of globalization, the immediate need was felt to document in details the under-explored ethnomedicinal practices of Lepchas of Dzongu valley. This paper reports 118 species, belonging to 71 families and 108 genera, under ethnomedicinal utility by the Lepchas for curing approximately 66 ailments, which could be grouped under 14 broad categories. Zingiberaceae appeared as the most used family (8 species and 5 genera). As per use pattern, maximum of 30.50% species are to cure stomach related disorders/ailments, followed by 19.49% for curing cut, wounds, inflammation, sprains and joint pains. Administration of medicine orally is recorded in 75% cases. Root and rhizome harvesting targeted 30 species. The changing scenario over time both at socio-cultural front and passing traditional knowledge interests from older to younger generation and rich ethnomicinal wealth of the oldest tribe of Sikkim are discussed in the light of conservation strategies and techniques to adopt.


Introduction
Documentation of traditional knowledge on ethno medicinal use of plants has been considered as a high priority [1][2][3][4][5] to support the discoveries of drugs benefiting mankind. In India, various communities use over 50% of the plant species of any ecosystem in ethnomedicine and in general over 7500 species are utilized in primary health care by various tribes [6]. The tribal populations, who have been the primary inhabitants of natural habitats, hold tremendous amount of traditional knowledge on the use of various biotic resources [4,7], which may have greater importance to the on-going research and discoveries in the field. It is well acknowledged in literature [2,8,9] that their age old practices of using plants to cure numerous ailments have paved the way to further discovery of many life saving drugs. In India, out of over 427 tribal communities in total, the north-east states, including Sikkim, boost to have over 130 major tribes, reaching in to a total sub-tribes or groups of about 300 [10]. The state of Sikkim, though only 7096 Km 2 in area is one of the rich depositories of biota [11]. This represents over 550 medicinal plants, which may offer incredible scope for the development of pharmaceutical sector as potential commercial hub, boosting economy of the state. Ethno-medicinal explorations and simultaneous prioritization of pharmaceutically important plant species for conservation through ex-situ cultivation have been identified as vital aspects for the drug industrial development [6,12,13]. In Sikkim, such exploratory researches on ethnomedicinal use of plants are not sufficiently taken up, especially targeting the remotely located tribal areas in the state; whichever is available mostly confined to simple preliminary listings (mentioned later in this section). The Dzongu valley in north Sikkim, India inhabits the largest population of the Lepcha tribe. The Dzongu valley, an officially demarcated reserve for Lepcha community bordering Khangchendzonga Biosphere Reserve, known for its vast plant wealth is one of the least attended areas on ethnomedicinal aspects, for being sacred and restricted, especially to outsiders.
The Lepchas of Dzongu valley, an isolated forest dweller, living harmoniously with nature over centuries, have accumulated a vast understanding on the use pattern of various wild products of the area. This suggests them as great traditional ethno-botanical practitioners. Sir J.D Hooker, during his botanical explorations to Sikkim Himalaya (1847-1851), mentioned Lepchas of Sikkim for their knowledge on the plants in splendid terms in his monumental work,"Himalayan Journal (1855)" [14]. The bamboo plant has been used quite commonly and exquisitely by the Lepcha community since their existence. Bamboo supplies a frame in the majority of constructions, such as houses and bridges. Lepchas seem to have gained marvel over the technical use of Bamboo, ranging from articles of routine requirement to artifacts, water distribution network, musical instruments, etc [15]. Bamboo is a summom bonum of their spirit. The Bamboo technology can be imported from this community. Lepchas in remoteness from modern facilities of the world got adapted to develop skills required to withstand difficult conditions of nature. Lepchas have become carrier of enormous understanding on the use of plants descended upon them through use of traditional medicinal cure to various ailments [16]. However, a general observation highlights that the Lepcha medicine man or the Lepcha healer, locally called 'Maon-doak', is known to restrict his medicinal practices and prescriptions only to Lepcha community, and he does not share or offer the same to the outsiders. The 'Maon-doak' believes that if his secret traditional knowledge of using plants is disclosed to any unauthorized person, the plants under use would produce adverse effects, and he may encounter ill-fate generated from the rage of the supreme deity of medicinal plants in the forest. This non-sharing attitude must have been one of the strongest reasons for the decline of this archaic system of medicine [14].
The cultural heritage of Lepcha tribe of Sikkim has been in the past and now a centre of attraction for several anthropological studies [15][16][17][18][19][20][21][22][23][24][25], as well as on Lepcha language, heritage and culture in general (http://home.wanadoo.nl/ heleen.plaisier/bibliography.htm; accessed on 17.4.2008, for a detailed compiled list of references) but on ethnomedicinal knowledge of Lepchas only a few sporadic publications are available documenting fragmentarily. Amongst them, as a part of ethnobiological study, Jana & Chauhan [26] have tabulated the use of 38 plant species curing various ailments by Lepchas in Dzongu, giving the plant name, part used, application, etc. Similarly, 21 species of medicinal plants used (part, specific use, and doses) by both Lepchas and Nepalese in north Sikkim, in general, were reported by Maiti et al [27], who further showed concern on the regular collection of plants by the Nepalese collectors. Jha [31]. Since, the Lepchas of Dzongu are known for their retention of rich cultural heritage, and especially in view of the on-going cultural and economic changes brought in by the process of globalization, the immediate need was felt to document in details the under-explored ethnomedicinal practices of Lepchas of Dzongu valley. The present study makes an exhaustive effort in investigating and documenting ethnomedicinal plants of Dzongu. The paper extended the list of such species describing their detailed practices along with quantitative analysis of the data. This study will present an updated and much improved document of the traditional pharmaceutical knowledge of a tribe of Dzongu valley. This effort should be seen serving not only as a sound base for resource assessment but an opportunity for developing scientific guidelines on access and benefit sharing regime on ethnomedicinal plants by the community people. The objectives of the present study is to provide field based assessment and documentation on, (i) authentic listing of plants used in traditional medicinal practices; (ii) the use part and the use pattern of the plants, preparation, ailments cured, etc., and (iii) describing conservation aspects of those plants for the drug.
The Lepchas were hunters and gatherers [21,34] and used to live complete nomadic lives. Since mid-nineteenth century, they began practicing settled agriculture [37] particularly because of increased production of large cardamom, as a cash crop. In addition, Lepchas also grow rice, maize, millet, wheat, buckwheat, pulses, and vegetables, and in some parts sugarcane and fruits, with animal husbandry as another important economic activity. The diet of Lepchas is supplemented with plants and mushrooms, tubers and rhizomes gathered from wild and produce grown in small kitchen garden such as ginger, chilies, beans, cucumber, garlic, sweet potatoes, yams and sugarcane. Originally, the Lepchas were the followers of the Shamanism; they converted to Bhuddism in eighteenth century, and since the middle of the nineteenth century, a significant number of Lepchas has converted into Chiristianity [38]; although, indigenous Lepcha Shamanism has managed to exist till today.

Study area and methodology
Study area An officially demarcated reserve for Lepcha community, the Dzongu, a Bhutia derived name meaning "a place with nine districts" [19], is located about 70 km north to the State Capital, Gangtok -in the north district of Sikkim, India. The Dzongu is bounded to the south-east by Teesta river and north-east by Tholung chu (river) and to the west by rising mountain leading to Khangchendzonga, the house of five treasures ['Kingtsoom Zaongboo Choo", Lepcha name for Mt. Khangchendzonga (3 rd highest mountain in the world) meaning 'bright auspicious forehead peak' that borders the Khangchendzonga Biosphere Reserve (KBR) at north. The KBR was officially notified in the year 2000, covering 2, 61,992 hectares area; the Dzongu valley people have traditional association with the reserve for their resources and religious affinity, and currently promoted eco-tourism by the state government. A fairly triangular shaped Dzongu landscape covers approximately 78 km 2 geographical areas extending between 27°28' -27°38' N lat. and 88°23' -88°38' E long. (as judged from Google Earth) along the 700 m to 6000 m amsl altitude. Dzongu further extends from Sheep-Gyer in the east to Sakyong-Pentong village in the west and Kishong Cho Lake in north to Lum village in the south. The area is characterized by diverse snowy mountainous landscape with steep and narrow valleys and gorges with well drained flanking slopes, receiving high rainfall between June and September. Owing to dense forest cover, the area experiences showers almost throughout the year. The area represents three climatic zones viz. subtropical, temperate and alpine. Further, the area may be divided into two parts, viz. Upper Dzongu; the western side of which can be entered through a bridge at Sankalang over river Teesta and the eastern side is connected by road at Theng via Toong prior to reaching Chungthang; and the Lower Dzongu, which can also be entered through a bridge at Sankalang in the eastern side and a bridge at Phedang near Dikchu bazaar (market) in the western side over the same river. Dzongu is the abode of majority of Lepchas [21]; however, as per 2004 official list of voters, it has a total population of approximately 4513 persons (ca. 10% of total Lepcha population of Sikkim), spreads over 38 villages.
The importance of Dzongu valley is further enhanced by the famous Tholung Gumpa, one of the oldest monasteries in Sikkim built in early 18 th century during the reign of Chogyal Chagdor Namgyal, the king. The Gumpa is situated at an altitude of 2600 m amidst sacred groove "a treasure house of nature", demarcated under buffer zone III of the Khangchendzonga Biosphere Reserve. Since the invasion of Sikkim by Gorkhas during late 17 th and early 19 th century, Tholung Gumpa (monastery) harbours sacred Buddhists and Sikkim relics that were brought here for safety by Lama Lhatsun Chempo, founder of the Tholung monastery. The Ecclesiastical Department, Government of Sikkim keeps these relics in sealed thirteen boxes under custody. In the presence of lamas of the Gumpa and the representatives from concerned department, these relics are taken out once in every three years in the month of April for public display. Tholung Gumpa has very sparse human habitation with merely 15-20 settlements of which 10-12 remain almost vacant throughout the year. The Kishong Cho or Kishong Lake, situated at an altitude of approximately 4200 m having religious significance for Buddhists, also forms a part of Dzongu valley. In addition, there are many sacred caves in Dzongu valley which are said to be used by the lamas for meditation in the past. Large Cardamom cultivation is practiced in the entire Dzongu valley, reaching up to Tholung Gumpa. Both in composition and value, the floristic wealth of Dzongu and its surrounding area is rich and diverse, representing a wide variety of tree species, shrubs, lichens, epiphytes, mosses and bamboos, which provides refuge to several endangered species of birds and animals. Without prior permission from the higher authorities, outside people are not allowed to visit Dzongu valley, being a restricted area [26].

Medicinal plant survey
At first, extensive literature and internet search was carried out to review and assess the existing information on the medicinal plants used by Lepcha tribe, as baseline for extensive research. To get first hand data and further for confirming authenticity of the existing information, extensive field surveys were undertaken between 2006 (groundwork) and 2007 (comprehensive) in Dzongu area, North Sikkim, India. Information was gathered, using semi-structured formats, interviews, and group discussions, on the indigenous uses of plant species as medicine by the Lepcha tribe. During the survey period, conversations with informants were held with the assistance of local resource persons. In view of their belief not to share their knowledge to the outsiders the collection of information was not easy. The objectives of the study were elaborated and efforts were made to take them into confi-dence that purpose of this study is just to document and preserve the traditional knowledge of Lepchas on medicinal plants. In total 125 informants (95 males and 30 females) were interviewed, which included 4 Moandoaks (Lepcha medicine man or Lepcha healer), 27 Thyongs (elderly person in village), 7 Bongthings or Padem (priest following Shamanism), 3 Monks, 2 Muns (a healer who exorcises demons, helps to heal illness and guides souls to the afterlife), 17 graziers and remaining 65 included people belonging to different categories like villagers, farmers, housewives, teachers, shopkeepers, forest managers, contractors, etc., of which 37 were males and 28 were females in different study villages (Passingdang, Lingdem, Fourthmile hamlet, Ruk Lu, Kayeem, Tingvong, Tholung Gumpa, Sakyong-Pentong). These informants were approached and requested to share their knowledge about the plants they use against different diseases, plant parts harvested, method of preparation, etc. All the informants were above 27 years in age. Friendly chats made with teenagers and youngsters and school children, of both genders, helped a lot in confidence building with tribal people. In some villages, the informants were not much cooperative to reveal the secret of their ethnomedicinal knowledge to the strangers unless they were taken in to confidence, which experienced rather as a difficult task, besides language problem. Adopting participatory and group interaction approach, data were further crosschecked. Surveys were also made in the wilderness along altitudinal transects reaching timber line zones (upto Temreng), surrounding natural habitats and the agricultural areas of villages. The help of local representatives was taken to approach the plants growing in areas and or specimens available in the villages with elderly people in some cases. Species were identified using standard Floras and books [9,39,40]. The restriction on the collection of any specimens, especially by the outsiders, for being the landscape as protected/sacred/restricted, suggested adopting the above strategy of field identification. The gathered field information was systematized and analyzed to draw a clear and updated picture of the ethnomedicinal use pattern of plants of Dzongu area in Sikkim. At the same time, efforts were made to compare and discuss the use of some of the medicinal plant species recorded in Dzongu valley with those reported for other tribal groups/traditional healers in India (Table 1).

Results
The study documented 118 medicinal plant species, distributed across 71 families and 108 genera, used by the Lepcha tribe of Dzongu area (Table 2). In terms of number of species used, Zingiberaceae appeared as the most prominent family (8 species, 5 genera), followed by Rutaceae and Poaceae (5 species each), Asteraceae, Rubiaceae, Moraceae (4 species each), Apiaceae, Cucurbitaceae, Solanaceae, Liliaceae, Ericaceae (3 species each) (page number not for citation purposes)    Aconitum heterophyllum Ranunculaceae Rhizome is dried up and taken to relieve body-ache, fever, cold, cough, nose discharge etc. 4 Aconitum spicatum Stapf. Ranunculaceae Rhizome is detoxified by non-stop boiling with water at least for 24 hours, and cut into small pieces and dried, and chewed in case of food poisoning, diarrhoea, cough, inflammation of intestine. Dried rhizome is powdered and consumed to relieve body pain, ear and nose discharge. 5 Acorus calamus Linn. Araceae External application of rhizome paste cures skin diseases and on the forehead in case of fever. Small piece of dried rhizome is taken curing distressing cough. Dried cut piece is given to child for speech clarity or to stammering child. 6 Aesandra butyracea (Roxb.) Baehni Sapotaceae Fruit juice applied on the body before sleeping to soften skin; fruit edible. 7 Ageratum conyzoides Linn. Asteraceae Leaf juice is applied externally to heal surface wounds. Decoction of herb is also given to cure stomach ailments such as diarrhoea, dysentery and intestinal colic with flatulence 8 Allium cepa Linn. Liliaceae Eating raw bulbs eaten raw reduces fever acting as cooling agent. 9 Allium sativum Linn. Liliaceae Raw bulbs are taken in case of indigestion and altitude sickness. Bulb paste cures skin diseases, and the bulb juice is poured in the ear to treat earache. Bulb fried with mushroom act as antidote on snake bite. To drive the snake away from the vicinity of the house during summer months, the rhizome is crushed to mix into with water to sprinkle around the house. 10 Amaranthus tricolour Linn. Amaranthaceae Curry prepared from green leaves stops diarrhoea. Seeds grounded into powder, mixed with water and taken as an infusion to cure general gastric problems. Beaten seeds are fried with butter and fed to pregnant women to lessen pregnancy pains. 11 Amomum subulatum Roxb. Zingeberaceae Gargle with seed decoction with water, is used to treat teeth and gum infection. Pounded root mixed with water treats urinary infection in cattle. 12 Ampelocissus Fermented seeds are taken with traditional drink as medicine during bodyache due to exhaustion. It is also given to the gastric patients.  Rhus semialata Murr. Anacardiaceae Sour juice of fruits is boiled with water, and concentration is further mixed with water and raw egg, treats diarrhoea and dysentery. It is also used as food preservative. 99 Rubia cordifolia Roxb. ex Fleming Rubiaceae Root decoction with water is given to cure urinary infection; paste is used as an ointment to skin diseases. Root is also used to make dyes.  (Figure 1). As per plant part used by Lepcha tribes for ethnomedicine, the maximum number of species are harvested for root and rhizome (34 species combined) and leaves (27 species), followed by fruit, seed, bark and whole plant (Figure 2). Further, destructive harvesting for the whole plant as medicine indicates the use of 9.32% species in the area. In the present study, a maximum of about 29% species are subjected to destructive harvesting using root/rhizome, which may be related to their possible vulnerability towards endangerment [41]. The cases of Aconitum ferox, A. heterophyllum, Picrorhiza kurrooa, Swertia chirayita, Valeriana hardwickii, etc. appeared in the same category.
The 118 medicinal plant species recorded from Dzongu are used to cure about 66 ailments, which authors grouped them under 14 broad categories ( Figure 3). Of which, 36 species (maximum) used to treat stomach related disorders such as diarrhoea, dysentery, indigestion, gas expelling and others; however, 23 species figured in curing cut, wounds, inflammation, sprains and joint pain ( Figure 1). The study revealed that 59.3% plant species are reported to be used to cure more than one ailment. External applications as well as internal consumption are involved in the treatment of diseases. Analysis of species level data discovered the oral (75.0 %), external application (44.4%), nasal (5.5%), eye (2.7%) and the ear (0.93%) as major administration route of ethnomedicine used. It was observed that most of the preparations include single plant species and in rare case the combination of two or more species. It was also observed that different parts of a single species are used to cure different diseases.
The study finds the used administrations are not standardized in general, but depend on the age and physical appearance of the patient, illness and diagnosis of the diseases [28,42,43]. Children are given small doses of medicine than considered in case of adult patients, which further depend on the type of illness and treatment realized appropriate by the local medicine man. The type of disease and level of its severity further decide the course of the frequency of treatments. Each medicinal plant is used either raw or in dried form as medicine. Especially, the underground parts are used in the dried form, which is either cut into small pieces or powdered, and stored [44].
On the collection and use of medicinal plants, about 70% respondents indicated Swertia chirayita as the most frequently used and highly extracted species (whole plant) for its applicability in many common diseases, such as, fever, cold, cough, diarrhoea, stomach-ache ( Use of Pandanus nepalensis as medicine is poorly mentioned in the literature though has important properties. This plant is abundantly available all along the Teesta valley and its tributaries in the warmer parts of the state, including lower parts of Dzongu. Belonging to monocot family it is a medium-sized tree up to 5-6 m in height typically having broad canopy and stout trunk, ringed with many leaf scars and dioeciously branched. The clustered drooping fruit resembles Ananas comosus, but without leaves at the apex of the fruit, which is seen eaten by monkeys and rats. As per Moan-doak, placing or tying up of young or tender leaves on the skin at the place of snake bite helps reduce the pain caused. It may also be chewed as breath sweetener. The fresh leaves also act as a cockroach repellant. The leaves were used for making handwooven mats, carrying bags, fishing bags, thatching roofs, etc. but a dying practice these days. The use of Sphagnum squarrosum (peat moss) and Usnea sikkimensis (old man's beard, a lichen) of the alpine region, in dressing and bandaging cuts and wounds because of their absorbency and insulation, has been reported by some of the elderly persons, who were the hunters and graziers at one time. S. squarrosum is also used as an important source of fuel in the area. Written records exist on the use of U. sikkimensis as a remedy for lung troubles, hemorrhage and asthma, and also the massaging scalp with plant powder helps strengthen hair [14]. Thyongs of Dzongu also reported that U. sikkimensis stops nose bleeding, prevents or treats foot blisters (if inserted inside the shoe) due to continuous wearing of hard leather shoes, and treats skin eruptions and boils (bandaged over the wound). This lichen is inserted in a bag and also used in the form of pillow by the graziers/shepherds. However, such uses of plants sound amazing and interesting to the present generations.

Discussion
In general, over 80% respondent under present study in Dzongu shared that in recent years, dependency on allopathic treatments has increased considerably over traditional health care systems. Loosening interest amongst in young generation, and tough and time consuming process of plant collection and gradually lacking in skill of specific identification, appeared as major reasons for declining trend in using traditional health care system. For living in the close nearness to the district headquarter by the exposures and involvement in developmental programmes offering them livelihood options as well the availability of primary health centers and sub-centers in each village in recent years have further diverted youngsters from using ethnomedicinal practices. Surprisingly, for some particular ailments like bone fracture and dislocation, most of the inhabitants still prefer herbal use rather than the allopathic treatment, as they like to avoid undergoing painful therapies of the later. Many natives still prefer and trust upon using traditional health care system as the excellent and much effective means to cure their ailments over allopathic drugs [42][43][44]. The species subjected to destructive harvesting due to uprooting underground part form over 29% in Dzongu. Often, the threatened taxa, if they are already having small and fragmented populations in a particular area, as well as growing in specific habitats [41], they could be susceptible to further endangerment, if species are approached to commercialization through wild harvesting. It would be crucial to assess their potential of availability, as resource, through population assessment. Ex-situ cultivation of such taxa would not only promote their conservation but also offer income opportunity to    (Table 1.).
Lepchas have learnt to make use of Costus speciosus for curing the disease infecting most sensitive part of the human body (veneral disease and the urinary tract infection), which is not mentioned by other tribes [47-50] under review (Table 1). Similarly, the leaf of Lantana camera, the dominant weed in the region, is being found used only by the Lepchas as an antiseptic and as a pain reliever; this use is not found with other tribes mentioned in this paper. Depending upon the immediate availability of the plant species, they have managed to make multiple uses of single species. For example, Urtica dioica, is used by the Lepcha tribe for curing diarrhoea and cough and the soup prepared from it is given to the pregnant women which helps is easy delivery of child other than bone fracture as used by Apatani tribe. Similar multiple use of another species, Cynodon dactylon, Drymeria cordata and Ficus religiosa, is recorded form Lepcha tribe of Dzongu (Table 1), such use is not reported from other tribes of the north-eastern Indian region indicating that the Lepchas having much more exploratory power and knowledge in comparison to the other existing tribes in the region.
Use of local medicinal plants by Lepchas ensures the continuity of indigenous knowledge associated with the species and has the definite bearing on the identification of their habitats, which are confined in the pockets of the most difficult hill terrain to some extent. The gradual decline in traditional use practices may, therefore, leads to the fading away of the indigenous knowledge associated with the plants in very near future. On the other hand, the people inhabiting Sakyong-Pentong, Tholung, etc., the places which are not approachable by roads, still found to be almost fully dependent on herbal health care system. The present study indicates that the Dzongu area is a rich reservoir of medicinal plants and associated ethnomedicinal practices offering great pharmaceutical potential. The knowledge for identification of medicinal plants, drug preparation and usage for medicines, as great potential amongst Lepcha tribes of Dzongu valley is confined to few old traditional practitioners chiefly. For their getting migrated to cities in search of better livelihood options Major group of ailments cured using the plant species in Dzongu valley, North Sikkim, India Introducing techniques of ex-situ cultivation of commercially viable species [12,51,52] would present a strong option of income generation to community people. To establish self sufficient primary health care system of this remotely placed tribal area, growing herbs in kitchen garden would not only supply raw material at household level but ensure the revival of traditional knowledge and conservation of valuable medicinal plants of the region. Development of kitchen garden growing herbs has greater benefit to train community tribal people on conservation through nursery practices at small scale before venturing into big ones. The current study may be of great use and interest to researchers, pharmaceuticals, foresters and medicinal practitioners. The documentation finds Dzongu valley a highly potential reservoir of high value medicinal plants and rich ethnomedicinal knowledge, and can also be a suitable agroclimatic zone for the cultivation of herbal plant species. Thus the current study will further help in both conservation of traditional ethnomedicinal knowledge as well as the development of native villagers.