Comparative phytochemical characterization of three Rhodiola species

In comparison to the well-recognized adaptogenic herb Rhodiola rosea, phytochemical constituents of two other Rhodiola species (R. heterodonta and R. semenovii) were elucidated and characterized. Chemical similarities among the three species were observed; however, each species displayed differences in phytochemical constituents. Cyanogenic glucosides were characteristic for all three species, but phenylethanoid or propanoid glycosides were detected only in R. heterodonta and R. rosea. A phenylethanoid glycoside; heterodontoside; was isolated from R. heterodonta. Proanthocyanidin oligomers and polymers, with different polymerization degrees, based on (−)-epigallocatechin gallate units (EGCG), were characteristic of all three Rhodiola species.