Finding new sources from "using different plants as the same herb": A case study of Huang-lian in Northwest Yunnan, China

Ethnopharmacological relevance: Traditional and local medicinal knowledge would be useful for finding pharmaceutical resources. Ethnopharmacological methods, especially quantitative analysis could help us to pre-screen herbs in field studies. "Using different plants as the same herb" is common in both traditional and local medicinal systems in China. In terms of medicine safety, it is not best choice, for it would lead to difficulty in controlling the quality, safety and efficacy of herbs. However, from the perspective of finding new resources for pharmaceutical industry, it would be beneficial. The usage of Huang-lian is one of the typical examples of "using different plants as the same herb". According to the previous Phytochemical and Pharmacological studies, berberine is the common effective compound of most of the species used as Huang-lian. Recently, berberine and other effective compounds of Huang-lian have gained much more attention and will become more popular in both medicinal researches and pharmaceutical industry. In our preliminary field work, we found that dozens of plant species might be used as Huang-lian by local people in Northwest Yunnan, an area well known by its rich biodiversity and culture diversity. These herbs might have potential value for pharmaceutical industry, for example, it could be used as the new resources to extract berberine and other effective compounds. Due to this, it is very necessary to collect, identify, document, and analyze the herbs used as Huang-lian in NW Yunnan. In the present study, we focused on that how to use traditional and local medicinal knowledge to find resources for pharmaceutical industry.

Material and methods: In the field work, interviews and participative observation were used. In the quantitative analysis of the local knowledge, Informant consensus factor (Fic), Use value (UV) and Relative frequency of citation (RFC) were used.

Results and discussion: A total of 230 key informants were interviewed and 29 plant species belonging to 8 families and 11 genera used as Huang-lian were collected in the study area. Diarrhoea had the highest value of Fic.xiana had the highest value of UV and RFC. The main effective compounds of most of these species were related to the protoberberine group of isoquinoline alkaloids, e.g. berberine, jatrorrhizin and palmatine, according to the previous phytochemical studies.

Conclusion: The range of sources of Huang-lian were very wide in NW Yunnan. Treating diarrhoea was the most common use of these species, most of which contained berberine. Based on the results of quantitative analysis, M. duclouxiana may had the greatest potential to future uses, e.g. as a resource for pharmaceutical industry. In the present study, we did not discuss whether the herbs used as Huang-lian could replace the standard Huang-lian in traditional or local medicine or not, and we just wanted to explore how this phenomenon could be used to find new resources for pharmaceutical industry.