Medicinal plants used in management of certain ailments by the Monpas of Dirang, Arunachal Pradesh, India

The Monpas of Arunachal Pradesh, India has rich traditional knowledge on traditional medicines, while, the current study attempts to document the traditional knowledge on the medicinal plants used by them. The field and herbarium techniques were followed to obtain the essential information on the use of medicinal plants. The collected plant species were identified with the consultation of taxonomic literature Floras and Herbaria. Altogether 16 medicinal plant species belonging to 13 families were reported to be used by the Monpa community of this region. Leaves (32%) were the most frequently used plant part, while the flowers (5%) were the least. A total of 16 different medical conditions were reported to be neutralized using these plants. As it was claimed by the locals, these medicinal plants are considered to have no side effects and have multiple health benefits. The plant species Oenanthe javanica , with the highest CIs (Cultural Importance Index) and URs (Use Report) score was reported to be the culturally most significant plant among all the medicinal plants used by the Monpas of this region. Moreover, ICF (Informants Consensus Factor) values specified that there was high agreement in the use of plants in the headache and gastro-intestinal ailments category among the users. The rich bio-resources of this region may be further explored to widen the potentiality of herbal medicines.


Introduction
India is one of the major Biodiversity centres of the world and is enriched by about 45,000 plant species (Hussain and Hore, 2008). The tribal communities residing in the country depend on the forest resources for their livelihood and use their indigenous knowledge to harvest the rich bioresource (Ramakrishnan et al., 2000). The entire Eastern Himalayan has been rated as one of the top 12th global Biodiversity Hotspots (Meyer et al., 2000).
The State of Arunachal Pradesh of this region is considered as the hub centre of potential plants with an officially recorded list of more than 500 species (Sarmah et al., 2000). The state comprises all the characteristic vegetation types of the country, thus, the region is also considered to be the centre of medicinal and aromatic plants (Kaul and Haridasan, 2000).
The indigenous knowledge on ethnomedicines of Arunachal Himalaya is very rich and diversified among the tribes (Dolo et al., 2006). Likewise, the Monpa community of this state has rich traditional knowledge on medicine. Through this research, an effort has been made to document the traditional knowledge on medicinal plants used by the Monpa community of Arunachal Pradesh. The study also focused on the use of the plant-based medicine as well as non-medicinal practices including spiritual healings.

Materials and Methods
Study area, ethnology, and culture Dirang in West Kameng District, Arunachal Pradesh is situated at 26º 28' N to 29º 30' N latitude and 91º 31' E to 97º 30' East longitude. The region resides on the bank of the Kameng river with an average altitude of 4900 ft AMSL.
This beautiful hill station is inhabited by the Monpa ethnic community, sharing their traditions and heritage with Western Bhutan. The Monpa belongs to the Tibeto-Mongoloid racial stock and believes in reincarnation and transmigration of the soul (Nima et al., 2011). They perform several dramatic dances of which "Achilamu" is the most popular. The Lossar (the local new year) and Choskar are among the major religious festivals celebrated once a year (Figure 1).
The Monpas are agriculturists, practice both shifting and settled types of cultivation (Nima et al., 2011).
Raring of Livestock such as yaks, cows, pigs, sheep, seasonal fishing, and hunting of wild animals are the primary source of income.

Demography of informants
A total of 50 informants were interviewed; of these, 35 were male and 25 were female (Table 1). The informants were categorized into five different age groups, i.e., 30-40, 40-50 and 50-60 (Table 1). Field survey and data collection The field and herbarium techniques were followed (Jain and Rao, 1977) to obtain the essential information on the use of medicinal plants. The survey was done with the help of questionnaires, which was followed by group interviews for comparative statements and authentication about particular plant species used in curing ailments. The necessary information on plants and part/parts used in curing different ailments were also recorded.
To authenticate the collected information, a survey was also conducted to visit the river banks, where the local people usually collect the medicinal plants. Further, the nature of ailments and symptoms were recorded through oral descriptions stated by the villagers. An ethnobotanical market survey was done to assess the commercial feasibility of certain species and information on their uses was collected from the local herbal traders. The collected plant species were identified with the consultation of taxonomic literature and Floras (Bentham and Hooker, 1977) and Herbaria of BSI (Itanagar). The Scientific name of the plants was crossverified visiting the website www.theplantlist.org.

Analysis of quantitative data
Informant Consensus Factor (Logan, 1986) was calculated using the formula: IFC=Nur−Nt/(Nur−1). Where "Nur" refers to the total number of use reports for each disease cluster and "Nt" refers the total number of species used for that cluster. This formula was used to determine the consensus among the respondents and to find out the homogeneity in the documented information. The URs was calculated for each species in the data set (Prance et al., 1987). The CIs was also calculated for all the collected plants (Tardio and Pardo-de-Santayana, 2008). All the calculations were done using 'ethnobotanyR' software.

Results and Discussion
Taxonomic evaluation of the reported medicinal plants A total of 16 medicinal plant species belonging to 13 families were reported to be used by the tribal community of this region for the treatment of various ailments (Table 2 and Figure 6). The family Lamiaceae was reported with 3 species and Piperaceae with 2 species; ratio of the family to species of the rest was maintained at 1:1 ( Figure 2). As depicted in Figure 3, the life forms of the collected plants include herbs (47%), trees (27%), shrubs (13%) and climbers (13%).  Monpas of this region are still depending on the plants for healing purposes. These plants were reported to be used in curing several diseases for many decades. Also, the properties such as easy accessibility, effectiveness, easily processed at a very affordable price make these traditionally available medicines more reliable and locally acceptable. The detail on these medicinal plant species including local name, plant parts used, medicinal properties, mode of administration, and their traditional uses are described in Table 2.
Several plant parts were used in curing ailments (Figure 4). Leaves (32%) were the most frequently used plant part, while the flowers (5%) were the least. A total of 16 different medical conditions were reported to be addressed using these plants ( Figure 5). These diseases comprise heart-related problems, high/low blood pressure, gums-related problems, indigestion, gastric, diarrhoea, blood clotting, headache, body ache, cancer, jaundice, piles, cold and fever, diabetes, aromatherapy, and hypertension. As per the local healers, these plants have several modes of administration, of which, decoction is the most common method of administration. Apart from being used in the preparation of herbal drug formulation, medicinal purposes, these plants also have other utilities. For instance, O. javanica and H. cordata are consumed as vegetables. The leaves of A. nepalensis are used in the preparation of traditional butter tea. Likewise, Z. simulans and L. cubeba are used as edible spices and flavouring agents while preparing traditional cuisines, the stem of G. fragrantissima is used as toothbrush, the raw berries of Gaultheria sp. and V. glaucoalbum are edible, the wood of R. arboreum are burned in rituals. Seed flour of P. australis is used in the preparation of varieties of traditional cuisines. Additionally, some of these medicinal plants have several records of their utility other than their therapeutic uses. H. cordata was also reported to have anti-bacterial and anti-inflammatory activities (Sekita et al., 2016). O. javanica is a valuable herb consumed by most Asian countries for food (Lu and Li, 2019). A. nepalensis, are also commonly been used in traditional agroforestry systems for shade, fodder, fuelwood, and timber (Rana et al., 2018). Rhodojuice, a processed juice of R. arboreum flower is recognized and now widely popular among the Indians (Srivastava, 2012). P. australis have multiple utilities including food, fodder, construction, fuel, fiber, etc (Zang et al., 2016).
It was also informed that these medicinal plants are considered to have no side effects with multiple health benefits. Despite their use as medicines, these plant species have been extensively used as vegetables, in religious ceremonies, and food plants as well. There was, however, no written documentation of this knowledge as it is transmitted only through oral communication.

Conclusions
The Monpas of this region have demonstrated their knowledge as potential users of plant-based therapy to cure various ailments. There is, however, a potential threat to these plants as a result of the increasing trend of habitat fragmentation of plants, cultural deviation, and acceptance of modern allopathic medicines. Thus, there is a need for awareness among the locals to conserve these medicinal plants in natural ecosystems with appropriate measures. Additionally, these rich resources may be further explored to widen the potentiality of herbal medicines.

Authors' Contributions
Conceptualization: LW; Writing and editing of original draft: TW; Supervision and validation: ST. All authors read and approved the final manuscript.
Ethical approval (for researches involving animals or humans) Not applicable.