Systematic chemical analysis of flavonoids in the Nelumbinis stamen.

The stamen of lotus, known as Nelumbinis stamen, has been used as the folk medicine and functional food for a long time, which showed good activities of anti-ulcer, anti-thrombosis, analgesic, anti-diarrhea, strengthen uterine contraction. The bioactivities of Nelumbinis stamen were attributed to the existence of flavonoids, its characteristic chemical constituents. A reliable method for comprehensive chemical analysis of flavonoids in Nelumbinis stamen by HPLC-DAD-MS was developed for the first time. The extraction protocol of flavonoids from Nelumbinis stamen was optimized by an orthogonal design. The chromatographic conditions were optimized, which exhibited similar level than that of the UHPLC platform allowing target compound identification in a shorter time with little solvent consumption. Moreover, similarity analysis, hierarchical clustering analysis and principal components analysis were successfully applied to demonstrate the variability of these Nelumbinis stamen samples.