Ethnobotanical survey of cooling herbal drinks from southern China

Background: Liang cha (cooling tea, herbal tea or cool tisane in Chinese) are herbal drinks widely produced in southern China and consumed by billions of people worldwide to prevent and treat internal heat as well as a range of associated health conditions. Globalization and renewed interest in botanical remedies has attracted growing attention in cooling herbal drinks by industry, scientists and consumers. However, there is a knowledge gap on the plant species used and commercialized for cooling herbal drinks in southern China and their associated ethnobotanical use, habitat and conservation status. This is the first study to document plant species used and commercialized as liang cha in southern China's Lingnan region and associated ethnomedical function, preparation methods, habitat and conservation status. Methods: Three hundred market surveys were conducted between 2010-2012 in the largest herbal drink producing region of China to record plants used for liang cha and to document knowledge on their medicinal function, habitat and conservation status. Product samples and voucher specimens were collected for taxonomic identification. Results: All informants harvest and cultivate plants for preparing herbal drinks for their medicinal, cultural and economic values. A total of 222 ethnotaxa corresponded to 238 botanical taxa (species, varieties or subspecies) belonging to 86 families and 209 genera were recorded as liang cha to treat health conditions in the study area. Recorded remedies consisted of one or several plant species to treat conditions classified into 27 major health conditions with clearing internal heat being the most common medicinal function. The habitat types of plants documented for use as liang cha include 112 wild harvested species, 51 species that are either wild harvested or cultivated, 57 cultivated species, and 2 naturalized species. According to China's Red List and CITES on conservation status, one of these species is endangered, one species is critically endangered, eight species are vulnerable, one is listed in CITES II, three are listed in Regional Red Data Book and the remaining 224 species are in the least concerned conservation category. Conclusions: The liang cha industry of southern China reflects the plant species richness and cultural diversity of the region. Future research on safety and efficacy of herbal drinks as well as ecological and cultural conservation efforts are needed for the sustainable growth of China's botanical industry.