Phytochemical Investigation of the Rejuvenating Herb Pueraria mirifica Using LC-MS/MS

Pueraria candollei var. mirifica (Airy Shaw & Suvat.) Niyomdham (for simplicity, Pueraria mirifica) is native to Thailand and known locally as “white Kwao Krua”. Its tuberous root has been used locally for centuries for its profound anti-ageing properties and is considered a “fountain of youth” for aged men and women. The rejuvenating properties of the root are correlated to several different classes of phytoestrogens, namely isoflavonoids, coumestans, and chromenes (comprising miroesterol, its isomers and derivatives). Among more than thirteen species of Pueraria (P.) in Thailand, P. mirifica possesses the most distinct estrogenic activity due to its uniquely high content of chromene compounds. The complex mixture of phytoestrogens in P. mirifica is important both for quality control and identification purposes, as well as for biological activity. Therefore, a simple, accurate and reproducible method to qualitatively and quantitatively describe the chemical constituents of P. mirifica is desirable. This research describes the analysis of P. mirifica roots by LC-MS/MS with special attention to isoflavonoid, coumestan and chromene components. Several novel miroesterol isomers and derivatives have been tentatively identified based on interpretation of MS/MS data.