Xanthones from the twigs of Garcinia oblongifolia and their antidiabetic activity

Three new xanthones, oblongixanthone F–H (1–3), along with eight known xanthones (4–11), were isolated from an EtOAc extract of the twigs of Garcinia oblongifolia. Their structures were elucidated by spectroscopic analysis including 1D- and 2D-NMR spectroscopy and mass spectrometry. The antidiabetic effects of all isolated compounds were evaluated by in vitro α-glucosidase and PTP1B inhibition assays. Compound 11 was the most active compound, and inhibited α-glucosidase and PTP1B with IC50 values of 1.7 ± 0.5 and 14.1 ± 3.5 μM, respectively. © 2017 Elsevier B.V.