integr med res 6 ( 2 0 1 7 ) 372–387 Available online at www.sciencedirect.com Integrative Medicine Research j ournal homepage: www.imr-journal.com Original Article Pharmacological, ethnopharmacological, and botanical evaluation of subtropical medicinal plants of Lower Kheng region in Bhutan a,∗ b c Phurpa Wangchuk , Karma Yeshi , Kinga Jamphel a Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia b Wangbama Central School, Ministry of Education, Thimphu, Bhutan c Non-communicable Disease Division, Department of Public Health, Ministry of Health, Thimphu, Bhutan a r a t i b s c t l e i n f o r a c t Article history: Background: The Bhutanese Sowa Rigpa medicine (BSM) uses medicinal plants as the bulk Received 13 May 2017 ingredients. Our study was to botanically identify subtropical medicinal plants from Received in revised form the Lower Kheng region in Bhutan, transcribe ethnopharmacological uses, and highlight 4 August 2017 reported pharmacological activities of each plant. Accepted 17 August 2017 Methods: We freely listed the medicinal plants used in the BSM literature, current formula- Available online 1 September 2017 tions, and the medicinal plants inventory documents. This was followed by a survey and the identification of medicinal plants in the Lower Kheng region. The botanical identification of Keywords: each medicinal plant was confirmed using The Plant List, eFloras, and TROPICOS. Data min- Bhutanese Sowa Rigpa medicine ing for reported pharmacological activities was performed using Google Scholar, Scopus, ethnobotany PubMed, and SciFinder Scholar. Lower Kheng Results: We identified 61 subtropical plants as the medicinal plants used in BSM. Of these, medicinal plants 17 plants were cultivated as edible plant species, 30 species grow abundantly, 24 species pharmacological activities grow in moderate numbers, and only seven species were scarce to find. All these species grow within the altitude range of 100–1800 m above sea level. A total of 19 species were trees, and 13 of them were shrubs. Seeds ranked first in the parts usage category. Goshing Gewog (Block) hosted maximum number of medicinal plants. About 52 species have been pharmacologically studied and only nine species remain unstudied. Conclusion: Lower Kheng region is rich in subtropical medicinal plants and 30 species present immediate economic potential that could benefit BSM, Lower Kheng communities and other Sowa Rigpa practicing organizations. © 2017 Korea Institute of Oriental Medicine. Published by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). ∗ Corresponding author at: Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns campus, McGregor Rd., Smithfield, Queensland 4878, Australia. E-mail address: [email protected] (P. Wangchuk). http://dx.doi.org/10.1016/j.imr.2017.08.002 2213-4220/© 2017 Korea Institute of Oriental Medicine. Published by Elsevier. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). P. Wangchuk et al/Medicinal Plants in Bhutan 373 survey and the botanical identification of LAMP in the Lower 1. Introduction Kheng region, which is in the central–southern belt of the subtropical zone in Bhutan (Fig. 1). Our survey/study of medic- Plants are the basis of both traditional medicines (TMs) and inal plants from Lower Kheng region addresses the important modern drug discoveries. More than 50,000 plant species are research questions including: Does Lower Kheng region host used in TM worldwide and majority of them are being used as many medicinal plants as Langthel Gewog under Trongsa 1,2 in Asian medicines. Asian medicines comprise oral-based district? What type of medicinal plants grow there? What folklore medicines (local healing system) and the scholarly is their status? Could Lower Kheng be used as an alterna- TM systems. While most of the folklore medicines remain tive collection site for harvesting LAMP in bulk quantities for neglected, undocumented, and are becoming rare or extinct MSP? Could Lower Kheng people benefit through the medici- due to fast-paced modernization, the scholarly TM systems nal plants collection program? Are there any scientific studies still thrive in many Asian countries including Bhutan. conducted to verify the ethnopharmacological uses of these In Bhutan, while some traditional physicians argue that plants? Our ethnobotanical survey findings involving Lower Sowa Rigpa originated in the 8th century CE with the advent of Kheng region are presented here for the first time. Mahayana Buddhism, many scholars believe that it was only in 1616 that Lama Zhabdrung Nawang Namgyal laid written foundation to this medical system. The Bhutanese Sowa Rigpa 2. Methods medicine (BSM) belong to the larger corpus of the Tibetan scholarly medical (TSM) system, which was derived from 2.1. Study area and plant sample size Chinese Traditional Medicine, Indian Ayurvedic Medicine, 3 Greco-Roman medicine, and the Persian medicine (Galenos). The study areas included the following Gewogs (blocks of However, the country’s culture, tradition, local medical prac- villages; Fig. 1): (1) Phangkhar Gewog (Pantang, Shilingtoed, tices, geography, and vegetation influenced the way BSM Kulumtay villages); (2) Goshing Gewog (Lichibi, Buddhashi, evolved independently over many centuries, making it spe- Lamtang villages); and (3) Ngangla Gewog (Ribarty, Manas, cific to Bhutan. The similarities and differences between TSM Sonamthang, Kagtong villages). Few sub-villages, which are 4 and BSM was described by us previously. One significant dif- made of 4–15 households, were combined with the big- ference between TSM and BSM is the use of medicinal plants. ger villages. For example, Lichibi village features 10 villages BSM was integrated with modern medical systems in 1967 including Thimbi, Samcholing, Mathangor, Lempong, Umling, and this integration policy facilitated the establishment of Tongphu, Dungur, Shantang, Drangling, and Toenkhar. Sim- a TM university, pharmaceutical factory, and 58 TM hospi- ilarly, Sonamthang village is made of four villages including tals and units in the country. While the medical university Sonamthang, Tungudemba, Marangdud, and Panbang town develops human resources required for providing TM ser- area. Buddhashi includes five villages: proper Buddhashi, vices, the pharmaceutical factory [known as the Menjong Bobtsar, Solongmed, Surphang, and Selingbee. All three of Sorig Pharmaceutical (MSP)] produces more than 100 differ- these Gewogs are today accessible by motor roads. ent polyingredient herbal formulations. These formulations The criteria and reasons for choosing these areas as our are prepared into different dosage forms and are distributed ethnobotanical study areas were: (1) there was unsubstanti- free-of-cost to the traditional hospitals and units wide across ated/anecdotal claim about the lush growth of LAMP in the the country. The BSM formulations uses both high- (HAMP) region; (b) no ethnobotanical study has been conducted in and low-altitude medicinal plants (LAMP). HAMP are cur- this region to date; and (3) Lower Kheng people are poor and rently collected from the alpine mountains of Lingzhi region their engagement in the medicinal plants collection, culti- [2500–6000 meters above sea level (masl)]. LAMP are collected vation, and marketing programs could help them generate from the temperate and subtropical valleys of Langthel region cash income. We used purposive and convenience sampling (600–2000 masl). Lingzhi and Langthel regions have been the method to identify and locate the medicinal plants in these collection sites for MSP for more than 48 years and the pres- three Gewogs. The plant population or the sample size was sure on the medicinal plants population in those two areas irrelevant in this study since our survey included all the medic- have increased significantly over the recent years. The gov- inal plants known and available within the study areas. ernment’s policy to expand the TM heath care services to all corners of the country would add even more pressure to 2.2. Study design, survey methods, and team the plant population in the current collection centers. The reflexivity collection of medicinal plants on a rotational basis from dif- ferent collection sites in the country is expected to reduce Our study was a literature-guided ethnopharmacological, their ecological pressure. Recently, an alternative collection pharmacological and ethnobotanical identification study. We site for HAMP has been identified in Choekhor Gewog under first reviewed the current traditional medicine formularies Bumthang District (Central Bhutan) and Dagala Gewog in 5 and the Sowa Rigpa medicinal plants list maintained by MSP. Thimphu (Western Bhutan). For HAMP identification, we followed similar protocols as However, no study has yet been conducted to determine described by us previously including the translation of tra- the suitability of an alternative collection site for LAMP. There- 6–8 ditional medical uses of the plants. The research team, fore, urgent need to identify more places with LAMP has been comprising a Drungtsho (traditional physician from National discussed at various levels of the Ministry of Health meetings Traditional Medicine Hospital), a Senior Smenpa (traditional