Comprehensive study on genetic and chemical diversity of Asian medicinal plants, aimed at sustainable use and standardization of traditional crude drugs

Our representative studies to achieve sustainable use of crude drugs and ensure their stable quality are introduced: comprehensive studies on genetic, chemical, and sometimes pharmacological diversity of Asian medicinal plants including Paeonia lactiflora, Glycyrrhiza uralensis, Ephedra spp., Saposhnikovia divaricata, and Curcuma spp., as well as their related crude drugs. (1) For peony root, after genetic and chemical diversity analysis of crude drug samples including white and red peony root in China, the value-added resources with quality similar to red peony root were explored among 61 horticultural P. lactiflora varieties, and two varieties were identified. In addition, an optimized post-harvest processing method, which resulted in high contents of the main active components in the produced root, was developed to promote cultivation and production of brand peony root. (2) Alternative resources of glycyrrhiza, ephedra herb and saposhnikovia root and rhizome of Japanese Pharmacopoeia grade were discovered in eastern Mongolia after field investigation and quality assessment comparing Mongolian plants with Chinese crude drugs. Simultaneously, suitable specimens and prospective regions for cultivation were proposed. (3) Because of the wide distribution and morphological similarities of Curcuma species, classification of some species is debated, which leads to confusion in the use of Curcuma crude drugs. Molecular analyses of the intron length polymorphism (ILP) markers in genes encoding diketide-CoA synthase (DCS) and curcumin synthase (CURS) and trnK sequences, combined with essential oils analysis, were demonstrated as useful for standardization of Curcuma crude drugs. The above studies, representing various facets, can be applied to other crude drugs.