This study was carried out with the communities of Khilang, Parche, and Sikles villages of Madi Rural Municipality (Ward no. 1) in Gandaki Province of western Nepal. Sikles is the largest village, situated on the mountainside at an elevation of about 1,700 m. The Sikles area (combinedly called for all three villages) is a part of the Annapurna Conservation Area, which is the largest conservation area in Nepal. The area was selected because of its diverse culture and rich biodiversity (Khakurel et al., 2020, 2021). Secondly, comprehensive documentation of medicinal plants was lacking although previous studies covered a small part of the region (Kumar Rana et al., 2015; Gurung and Rajbhandary, 2017).

Geographically, Sikles lies between the upper subtropical to the lower alpine regions but mostly covers a temperate region. Altitudinal and climatic variations create high diversity of plants in the Sikles area which consist of upper subtropical to lower alpine vegetation (Figure 1). Alnus forests, mixed forests, broad-leaved forests, bushes, and high-altitude grasslands are available in the region. This area is characterized by typical assembles of both western and eastern Himalayan floral elements (Khakurel et al., 2020).

A total population of all three villages is about 2,418, among which Gurungs account for 70% (CBS, 2011). The Gurungs are one of the major ethnic groups of Nepal traditionally lived in mid-to high-hills possessing many generations of experience with the local vegetation. This community has a unique adaptation to different environmental conditions, as revealed by their culture and livelihoods (Messerschmidt, 1976). Agriculture is the main livelihood strategy adopted in the area. In addition, nature-based tourism has contributed largely in local livelihood.

Average age of the informants was 47 with 72 maximum and 21 minimum. The average years of experience of using one or more medicinal plants among informants was 14 while 45 was maximum. Since subset of socioeconomic factors such as gender, age, length of residence in the particular area, and occupation play crucial role in the knowledge acquisition about medicinal plants (Voeks, 2007; Kutal et al., 2021), it is important to understand these factor while collecting information.

We used gender as a first classification criterion to understand whether the knowledge regarding medicinal plants varies among them and how this variable influences the structure of local medical systems. Here, the one-way ANOVA demonstrated that the number of plants listed by women and men informants was not significantly different (p = 0.1023) although, on average, more medicinal plants were reported by male informants (12.325 ± 3.725) than female informants (10.923 ± 2.425) (Mean ± S.D.). Similar results were obtained by Joshi et al. (2020) in Makawanpur (Nepal) and Bibi et al. (2022) in Himalayan region of Pakistan, where gender had no influence on medicinal plants knowledge. Torres Avilez et al. (2016) in their meta-analysis revealed no significant difference between the genders although there was significant difference in country and continent levels. On the other hand, women stands more with method of preparation and mode of administration of different medicinal plants. This dissimilarity between genders may be due to the fact that men generally manage the fieldwork and earning and travel high altitude for medicinal plant collection while women manage mostly the indoor activities and domestic life, which are highly associated with herbal preparations and uses.

Age was used as second classification criterion to find out knowledge distribution among informants. Our result shows that the knowledge of the participants and age had a positive significant correlation (R ² = 0.82, p < 0.05) (Figure 2). Thus, elder people tended to know more about medicinal plants than their younger counterparts. Particularly, age between 45 and 65 years cited higher number of medicinal plants and their uses comparing to other age groups.

Similar pattern of knowledge distribution is reported from Nepal (Rijal, 2008; Luitel et al., 2014), Mexico (Benz et al., 2000), Bolivia (Reyes-García et al., 2006), Ethiopia (Yineger et al., 2008), and Pakistan (Amjad et al., 2020). Reasons for greater knowledge with increasing age could be numerous and have to be interpreted with caution (Al-Fatimi, 2019; Weckmüller et al., 2019). It is logical to mention that with progressive age, people have more time to accumulate knowledge (Voeks and Leony, 2004). Discussion session with young people (n = 14 and average age 16 years) showed that they could name only a few medicinal plants. Other information regarding use, collection sites, and preparation methods was restricted to a very few participants. This demonstrates the gap in knowledge transmission, a common threat to traditional knowledge observed elsewhere (Geissler et al., 2002; Bruschi et al., 2019; Sousa et al., 2022).

A total of 115 wild medicinal plant species belonging to 106 genera and 71 families were reported in this study. Among them nine species were pteridophytes, two species were gymnosperms and remaining 104 species were angiosperms (Supplementary Table S1). The present report of 115 medicinal plant species is about 38% of the total plant species reported from the study area (Khakurel et al., 2020). Uprety et al. (2011) reported only 24% of total flora used as medicinal in Tanahun district. This indicates that the area is an excellent reservoir of plant species of medicinal value. According to Giday and Teklehaymanot. (2013) high diversity of medicinal plants is attributed to good vegetation cover which in turn implies their significant role in plant-based traditional medicine in meeting basic primary healthcare needs. Comparing to the previous study in the same area conducted by Kumar Rana et al. (2015) who reported 42 species and Gurung and Rajbhandary (2017) who reported 66 species, our study reported relatively high number of medicinal plant species with some new reports. Both of the previous studies covered only a small part of the study area but this study covered larger area, included more participants and also covered different seasons. Regarding the origin of plants most of the species were naturalized species with few exotic species as Ageratum conyzoides L. [Asteraceae], Cynoglossum zeylanicum (Vahl) Thub. ex Lehm. [Boraginaceae] etc.

Of the total species reported, 65 (58%) were herbs followed by 24 (21%) trees, 15 (13%) shrubs, and 10 (8%) climbers. This distribution pattern in different life forms is similar to other studies from Nepal (Shrestha and Dhillion, 2003; Kunwar et al., 2006; Uprety et al., 2010). The dominance of herbs could be explained by the fact that the study sites are located in higher elevations ranges thus diversity of herbs or shrubs is higher than that of trees. Use of shrub is, however, less common than use of trees for medicinal purposes (Rokaya et al., 2010). In fact, the study area harbors highest number of herbs (Khakurel et al., 2020). Asteraceae and Rosaceae were the dominant families with six species each followed by Gentinaceae and Ranunculaceae with four species each. Similarly, Berberidaceae, Asparagaceae, Polygonaceae, Lamiaceae, Solanaceae, Apiaceae, and Orchidaceae had three species each. Similar accounts of over utilization of these families are common in different parts of Nepal (Kunwar and Bussmann, 2008; Rokaya et al., 2010; Ambu et al., 2020; Kutal et al., 2021; Kunwar et al., 2022).

Altogether 13 parts (including latex) of the plants were used to treat different diseases. In case of some species multiple parts were used (13 species). Roots (22.80%) were the most used plant parts followed by leaves (21.93%), whole plant (20.18%), and bark (10.53%) (Figure 3). The whole plant was also used, mostly in the case of herbs. Generally, underground parts (roots/rhizomes/bulbs/tubers) were most frequently used. These results show consistency with the other ethnobotanical studies in the Himalayan regions of Nepal (Rokaya et al., 2010; Uprety et al., 2010). Underground parts of plants are the most preferred parts for medicinal purposes possibly because they contain higher amount of bioactive compounds than other parts (Srithi et al., 2009). Excessive use of reproductive parts and roots for the medicine has a negative effect to the population of plants resulting in the declining plant population (Giday and Teklehaymanot, 2013).

According to the respondents, there are certain medicinal plant species that should be collected on specific time or day for their high medicinal efficacy. For instance, Dactylorhiza hatagirea (D. Don) Soó [Orchidaceae], Aconitum gammiei Stapf [Ranunculaceae] and Hymenidium benthamii (Wall. ex DC.) M.G. Pimenov & E.V. Kljuykov [Apiaceae] were collected only on Tuesday and respondents believe that the tuber collected from these species on Tuesday had effective medicinal property.

The methods of preparation and administration of medicinal plants were diverse. Some formulations were prepared using single species (92 species) while others were prepared using multiple species (22 species). For example, the paste prepared from the stem of Rheum australe D. Don [Polygonaceae], Dendrobium amoenum Wall.ex Lindl. [Orchidaceae], and Prunus cerasoides D. Don [Rosaceae] were used in bone fracture. Rhizome of Acorus calamus L. [Acoraceae] was chewed to get relief from cough and throat pain. A cooked vegetable prepared from young shoot of Phytolacca acinosa Roxb. [Phytolaccaceae] was used to cure stomachache and diarrhea. Paste (40%) was the most common preparation followed by juice (18.23%), powder (10%), and decoction (7%) (Figure 4). Some 12% species were also chewed or eaten directly. Paste, powder and juice are the popular methods of preparation of medicinal plants in other parts of Nepal (Rokaya et al., 2010; Uprety et al., 2010).

The most common mode of administration of medicine is oral (65%, n = 75), followed by external application (32%, n = 31), and inhalation (4%, n = 4) as also reported by (Bhattarai et al., 2010; Luitel et al., 2014).

Medicinal plants were used to treat 23 different ailments. Highest number of species (22) were prescribed in stomach problems (abdominal pain, indigestion, gastric, constipation, intestinal problems) followed by 18 in fever, 16 in skin problems (mumps, scabies, and small wounds), 13 each in cut and wounds, burns, and diarrhea and dysentery (Table 1). Regarding reliability of the use reports, the use of the plants obtained in our studies compared with the ethnobotanical publications of Nepal shows a good accordance (Coburn, 1984; Lama et al., 2001; Manandhar, 2002; Shrestha and Dhillion, 2003; Baral and Kurmi, 2006; Bhattarai et al., 2006; Kunwar et al., 2006; Kunwar and Bussmann, 2008; Rokaya et al., 2010; Uprety et al., 2010; Malla et al., 2015; Gurung and Rajbhandary, 2017; Adhikari et al., 2019). This similarity is of great significance because identical plant use by different people from different areas may also be a reliable indication of curative properties (Uprety et al., 2010). For example, different previous studies shows that D. hatagirea is used for stomach problems which was consistent with the current study. Similarly, Swertia chirayita (Roxb.) H. Karst. [Gentianaceae] previously reported to cure fever, headaches and stomach problems which is also good accordance with the current results.

Empirical observation on the use of medicinal plants by the Gurung people on the Kaski district needed to be substantiated with phytochemical and pharmacological studies in order to corroborate their bio-efficacy. Comparisons of local uses and phytochemical/pharmacological properties for most of the medicinal plants showed that traditional use was coherent with known pharmacological and phytochemical properties in most of the cases. For example, Artemisia indica Willd. [Asteraceae] is reported to use for skin problems form our study, phytochemical investigation shows that it has antimicrobial properties (Rashid et al., 2013). Similarly, Paris polyphylla Sm. [Melanthiaceae] is used for the stomach problems. Phytochemical investigations shows that its methanolic extract is gastro-protective as well as anthelmintic properties (Matsuda et al., 2003). In addition, Bergenia ciliata (Haw.) Sternb. [Saxifragaceae] has multiple used mainly in gastrointestinal problems and skeletal problems, pharmacological investigations revealed that it contains antioxidant and anti-inflammatory properties (Ahmad et al., 2018; Zafar et al., 2019). The major aim of the ethnobotanical field studies is to provide main plants of the certain region to perform further phytochemical and pharmacological studies (Andrade-Cetto, 2009). Our study also provide numerous plant species which shows important by quantitative data promising for further phytochemical investigations. Species with high use value but less pharmacologically investigated need to focus for further study. Species such as Pedicularis siphonantha D. Don [Orobanchaceae], Polygonatum cirrhifolium (Wall.) Royle [Asparagaceae], Swertia paniculata Wall. [Gentianaceae], and Tectaria coadunata (J. Sm.) C. Chr. [Tectariaceae] needs further attention.

By comparing the recorded medicinal plants from this study with the other research and database of Nepal, we found that two species namely Berberis concinna Hook. fil. [Berberidaceae] (used for fever), Hymenidium benthamii (Wall. ex DC.) M.G. Pimenov & E.v. Kljuykov [Apiaceae] (for cough and cold) have not been reported previously as medicinal plants. Detail phytochemical investigations seems promising for these species.

Forests, fallow lands, and grasslands were predominant collection sites for the medicinal plants. Of the total species, 89 species were reported to be collected from forests followed by 21 species from grasslands, 10 species from fallow land, 4 species from roadside, and 3 species from riverside. Some specific plants are habitat specific such as B. ciliata (H is found in rocky areas in lowland while Neopicrorhiza scrophulariiflora (Pennell) D.Y. Hong [Plantaginaceae] is found in the rocky slopes in high altitude. The habitat of the medicinal plants can be divided into the two parts in terms of collection time and altitude - lowlands (between 1800 m and 3,000 m; near and around villages, collection time within a day, collection areas easily accessible) and highlands (above 3,000 m; far from villages, collection takes more than a day, collection areas remote and hard to access). Out of the reported species, 96 species are found in the lowlands and 17 species were found in the highlands with 10 species common in lowlands and highlands (Figure 5). Generally, collection of highland medicinal plants is difficult and hence storage of such species for further use is common practice in the study area.

Collection of most of the medicinal plants from wild habitats is a common practice in Nepal (Kunwar et al., 2006; Rokaya et al., 2010; Luitel et al., 2014; Shrestha et al., 2016; Uprety et al., 2016) and elsewhere (Pieroni, 2000; Abbas et al., 2016; Singh et al., 2017; Kassa et al., 2020). Many medicinally important plant species were reported to be found in lowlands near villages as these are mid-altitudinal ranges (1,700–2,200 m). This is in line with Kunwar and Bussmann (2008) who reported an increase of medicinal plant species with increasing altitude up to about 2000 m. The medicinal plant diversity corresponds with total richness of plant diversity in Nepal (Bhattarai and Vetaas, 2003), however, the high value species were reported from the highland areas.

Many plants used in traditional medicine or food have demonstrated some toxicity (Hammad et al., 2019). Nevertheless, plants used in traditional medicines have been considered safe as a result of the long history of use in the treatment of diseases based on knowledge accumulated over several centuries. In many cultural settings, toxic fatalities have been rare due to systematic selection of medicinal plants (Fennell et al., 2004). In our study also, local people had extensive knowledge about differentiating toxic and non-toxic medicinal plants on the basis of morphology or phenology of the species. For example, species from genus Aconitum and Arisaema have both medicinal and poisonous species which is distinguished by the local people. Generally, medicinal plants contain bioactive compounds which demonstrate both intra- and inter-species variation in type and content (Vaou et al., 2022).

Besides, studies documenting traditional knowledge about the use of medicinal plants rarely contain information on potential toxicity of the plants. This could be because such studies tend to focus more on the therapeutic property rather than on toxicological information (Botha and Penrith, 2008). This failure to document and contextualize potential toxicity of the plants in healing traditions and healing practitioners’ methods and approaches to treatment does not promote the safe use of medicinal plants outside the cultural boundaries (Rasool et al., 2022).

More than 78% of the respondents mentioned that the population of the wild medicinal plants is declining while 15% were unaware and the rest mentioned that the status of medicinal plants is unchanged. Majority of the informants (40%) pointed out that the unsustainable harvesting including premature collection to meet trade demand is the major cause for decreasing population in the wild. Species with high traded values such as A. gammiei, Asparagus racemosus Willd. [Asparagaceae], L. neesiana, and N. scrophulariiflora and D. hatagirea were included in this category (Figure 7). Destruction of the habitat including deforestation and habitat fragmentation was second major factor responsible for decreasing the wild population of the medicinal plants. Other causes mentioned by the respondents were lack of proper forest management system and climate change. Overexploitation, increased harvesters, indiscriminate collection, uncontrolled deforestation, and habitat destruction are major threats for medicinal plants around the globe including in Nepal (Bhattarai et al., 2006; Kunwar and Bussmann, 2008; Abbas et al., 2016; Chen et al., 2016). However, it is important to note that not all medicinal plants are affected in the same way by harvesting pressures (van Andel and Havinga, 2008), some plants having multiple biological characteristics such as habitat specificity, distribution range, population size, species diversity, growth rate, and reproductive system play crucial role in the plants availability (Wagh and Jain, 2013; Chen et al., 2016). Root, leaves, and tubers play vital role in the life cycle of the plants, therefore, overharvesting of these parts should be minimized. There is a need for quantitative estimation of threatened species and such species require immediate action for conservation as also pointed out by Taylor et al. (2005).

Only 5% of the people were cultivating one or two medicinal plants in small scale in the backyard. These species were P. polyphylla, L. neesiana, B. ciliata and S. chirayita. Some of the species fall under different conservation status and threat categories of different conservation agencies. For example, Euphorbia royleana Boiss [Euphorbiaceae], Dioscorea deltoidea Wall. ex Griseb. [Dioscoreaceae], Alsophila spinulosa (Wall. ex Hook.) R. M. Tryon [Cytheaceae], Nardostachys jatamansi C.B Clarke. [Caprifoliaceae], Taxus wallichiana Zucc. [Taxaceae] D. amoenum and Coelogyne cristata Lindl. [Orchidaceae]. are listed in Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix II category. Also, some species included in the International Union for Conservation of Nature (IUCN) red list category are N. jatamansi. (Critically Endangered), T. wallichiana Zucc. (Endangered) and P. polyphylla (Vulnerable). Twenty-two species also fall under Conservation Assessment Management Plan (CAMP). Species under CAMP include Aconitum spicatum (Brühl) Stapf [Ranunuculaceae], A. racemosus, Maharanga emodi (Wall.) A.DC. [Boraginaceae] etc. This reveals that these species need more attention for conservation than other species. As there is high diversity of medicinal plants, the conservation of medicinal plants also means conservation of plant biodiversity (Hamilton, 2004). Therefore, the actions and plans should be formulated accordingly.