Three new xanthones from Swertia bimaculata and their anti-5α-reductase activity

Three new xanthones (1–3), together with five known ones (4–8), were isolated from whole herb of Swertia bimaculata. Their structures were established on the basis of detailed spectroscopic analysis (1D- and 2D-NMR, HRESIMS, UV, and IR) and comparison with data reported in the literature. New isolates were evaluated for their anti-5α-reductase activity. The results revealed that all new compounds showed weak activity with reductase inhibitions of 40.5 ± 2.8, 38.6 ± 2.5, and 48.9 ± 3.0%, respectively.