Using widely targeted metabolomics profiling to explore differences in constituents of three Bletilla species.

Bletilla striata has been used in traditional Chinese medicine for thousands of years to treat a variety of health diseases. Currently, metabolic causes of differences in medicinal values are unknown, due to the lack of a large-scale and comprehensive investigation of metabolites in Bletilla species. In order to gain a better understanding of the major chemical constituents responsible for the medicinal value, this study aimed to explore the metabolomic differences among three Bletilla species (Bletilla striata: Bs, Bletilla ochracea: Bo and Bletilla formosana: Bf). There were 258 different metabolites between 'Bo' and 'Bf', the contents of 109 metabolites had higher abundance, while 149 metabolites showed less accumulation. There were 165 different metabolites between the 'Bs' and 'Bf', content of 72 metabolites was increased and content of 93 metabolites was decreased. There were 239 different metabolites between the 'Bs' and 'Bo', content of 145 metabolites was increased and content of 94 metabolites was decreased. In the Bo_vs_Bf, Bs_vs_Bf and Bs_vs_Bo groups, the major differential categories were flavonoids, phenolic acids, organic acids and alkaloids. Moreover, the differential metabolites were clustered into clear and distinct profiles via K-means analysis. In addition, the major differential categories were flavonoids, phenolic acids, organic acids and alkaloids. The 'Flavonoid biosynthesis' (ko00941) and 'Phenylalanine metabolism' (ko00360) pathways were significantly enriched in Bo_vs_Bf, Bs_vs_Bf and Bs_vs_Bo comparisons. These results clarify the metabolomics in different Bletilla species, as well as providing basis for the phamaceutical value of novel species of Bletilla.