Quantitative Determination of Principal Alkaloid and Flavonoid Constituents in Wintersweet, the Flower Buds of Chimonanthus praecox

A quantitative analytical method has been developed for four alkaloids (1-4), identified as constituents responsible for the melanogenesis inhibitory activity of the extracts of wintersweet, the flower buds of Chimonanthus praecox (L.) Link (Calycanthaceae). Concurrently, a quantitative analytical protocol has been developed for five flavonoids (5-9), which also exhibited inhibitory activity. To approve the validity of the developed protocols, five extracts of the flower buds collected in Chinese market were evaluated. The optimum conditions of separation and detection of these alkaloids (1-4) and flavonoids (5-9) were achieved on a common ODS column using a MeOH-H2O mobile phase with different additives [Et2NH for alkaloids (1-4); acetic acid for flavonoids (5-9)]. The results indicated that these assays were reproducible and precise, and could be readily utilized for evaluation of the melanogenesis inhibitory activity of wintersweet on the basis of the content of the functional species. The principal flavonoid constituents (5-9) also exhibited lipid accumulation inhibitory activity.