Ethnomedicinal plant diversity in Thailand.

ETHNOPHARMACOLOGICAL RELEVANCE: Plants have provided medicine to humans for thousands of years, and in most parts of the world people still use traditional plant-derived medicine. Knowledge related to traditional use provides an important alternative to unavailable or expensive western medicine in many rural communities. At the same time, ethnomedicinal discoveries are valuable for the development of modern medicine. Unfortunately, globalization and urbanization causes the disappearance of much traditional medicinal plant knowledge. AIM OF THE STUDY: To review available ethnobotanical knowledge about medicinal plants in Thailand and to estimate its diversity. METHODS: Information about ethnomedicinal uses of plants in Thailand was extracted from 64 scientific reports, books, and theses produced between 1990 and 2014. Plant identifications in the primary sources were updated to currently accepted names following The Plant List website and the species were assigned to family following the Angiosperm Phylogeny Website. Use Values (UV) were calculated to estimate the importance of medicinal plant species (UVs) and families (UVf). Medicinal use categories, plant parts used, preparations of the medicine, and their applications were noted for each use report. RESULTS: We found 16,789 use reports for 2187 plant species in 206 families. These data came from 19 ethnic groups living in 121 villages throughout Thailand. The health conditions most commonly treated with medicinal plants were in the categories digestive system disorders, infections/infestations, nutritional disorders, muscular-skeletal system disorders, and genitourinary system disorders. Plant families with very high use values were Fabaceae, Asteraceae, Acanthaceae, Lamiaceae, and Zingiberaceae and species with very high use values were Chromolaena odorata (L.) R.M.King & H.Rob., Blumea balsamifera (L.) DC., and Cheilocostus speciosus (J.Koenig) C.D.Specht. Stems and leaves were the most used plant parts, but also other parts of the plants were used in medicinal recipes. The most common way of using the medicinal plants was as a decoction in water. CONCLUSION: We found 2187 plant species that were used in traditional medicine in Thailand. Of these a few hundred had high use values, suggesting that they may produce bioactive compounds with strong physiological effects.

Ethnobotanical study of medicinal plants used by Tai Yai in Northern Thailand.

ETHNOPHARMACOLOGICAL RELEVANCE: We studied traditional knowledge of medicinal plants used by Tai Yai people in Northern Thailand. We documented traditional medical practices and determined importance among the Tai Yai. This paper reports on knowledge in usage of medicinal plants of the Tai Yai people in Northern Thailand. MATERIALS AND METHODS: Interviews were conducted in 4 Tai Yai villages in Mae Hong Son and Chiang Mai provinces whose inhabitants immigrated from Myanmar at different times. Discussions and interviews were held with 126 key-informants (56 males and 70 females) ranging in age from 16 to 80 years in three age groups (age 16-40, 41-60, and 61-80). We calculated the informant consensus factor (ICF) for use category, use value index (UV) for use report of plant. We tested differences between the knowledge of different age groups and locations using principal component analysis (PCA). RESULTS: These Tai Yai people used of 141 medicinal plants belonging to 59 families. Of the medicinal plant species, the highest percentage was in the family Euphorbiaceae: Croton acutifolius and Croton roxburghii. The highest number of Informant consensus factor was for metabolic system disorders. Overall, Tai Yai people use medicinal plants to cure many sicknesses such as hypertension, lumbago, wounds, puerperium, kidney disorders, kidney stones, coughs, fevers, hemorrhoids, flatulence and malaria. There were no significant differences in knowledge of plants usage among villages of different ages. In addition, the knowledge of the plants was not significantly different between men and women. However, we found that the younger had less experience with and knowledge of medicinal plants than older people. CONCLUSIONS: The result indicates loss of accumulated knowledge of medicinal plants and traditional use. Although, the medicinal plant knowledge was passed from one generation to the next by word of mouth, the detailed documentation of medicinal plants and their use may effectively prevent the knowledge-loss through time.

Medicinal plants used in Hmong women's healthcare in northern Thailand.

ETHNOPHARMACOLOGICAL RELEVANCE: We studied traditional knowledge of medicinal plants used for women's healthcare in three Hmong villages in northern Thailand and determined how prevalent such knowledge is. We documented traditional medical practices and determined which of the species used are culturally important among the Hmong. MATERIALS AND METHODS: We interviewed six key informants and 147 non-specialist informants about their traditional knowledge of medicinal plants used in Hmong women's healthcare. We selected nine species that were known in all three villages as the domain for questionnaire interviews with 181 additional and randomly selected non-specialist informants. We calculated the Cultural Importance index (CI) for each species and use category. We tested normality of the data, age correlations, and gender correlations with Kolmogorov-Smirnov tests, Spearman's rank correlation coefficient, Kruskal-Wallis test, and Mann-Whitney tests. RESULTS: We documented traditional knowledge of 79 medicinal plants used in women's healthcare. Of these, three species were culturally important to the Hmong. Our questionnaire interviews revealed significant difference in traditional medicinal plant knowledge between genders and age groups. CONCLUSIONS: The Hmong people in northern Thailand possess large amounts of traditional knowledge related to women's healthcare and plants used for this purpose. However, this knowledge, even for the culturally important species, is not possessed by all Hmong and there were signs of knowledge erosion. Preservation of the Hmong intellectual heritage related to medicinal plants used in women's healthcare requires intensive traditional knowledge dissemination to the young Hmong generation.

Medicinal plant knowledge and its erosion among the Mien (Yao) in northern Thailand.

ETHNOPHARMACOLOGICAL RELEVANCE: We studied local knowledge and actual uses of medicinal plants among the Mien in northern Thailand, documenting traditional medical practices and its transfer between generations. AIM OF THE STUDY: With the assumption that discrepancies between knowledge and actual use represent knowledge erosion, we studied whether actual use of medicinal plants corresponded to people's knowledge of such uses. MATERIALS AND METHODS: We used local knowledge from four specialist informants as the domain for semi-structured interviews with 34 randomly selected non-specialist informants. We calculated informant consensus, use value, and fidelity level for each species and use category and performed statistical analyses with Kolmogorov-Smirnov tests, Pearson correlation coefficient, Spearman's rank correlation coefficient, and paired-sample t-tests. RESULTS: We found significant discrepancies between knowledge and actual use of medicinal plants. The number of known and actually used plants increased with increasing informant age and decreased with increasing years of formal education. CONCLUSIONS: Medicinal plant knowledge and use in these Mien communities is undergoing inter-generational erosion because of acculturation and interrupted knowledge transmission. Preservation of Mien medicinal plant intellectual heritage requires continued documentation concerning use, conservation, and sustainable management of this resource, which should be publicized to younger Mien.