Chromanopyrones and a flavone from Hypericum monogynum.

Six new compounds, including three pyrone derivatives (2-4), one new flavone (5), and two new naturally-occurring compounds (1 and 6), together with 16 known compounds were isolated from the leaves and twigs of Hypericum monogynum. In addition, compounds 2-4 are racemates. Their structures and absolute configurations were determined on the basis of extensive analysis of spectroscopic data and ECD calculation. All compounds were evaluated for the inhibitory effects on α-glucosidase, compounds 1, 5, and 7 showed moderate inhibitory activities with IC values of 161.46, 257.78, and 11.54μg/ml, respectively. Compound 8 exhibited weak anti-oxidant activity with IC value of 12.55μg/ml.