A new stilbene derivative from the lianas of <i>Gnetum montanum</i> Markgr

Gnetum montanum Markgr., a species belonging to the family Gnetaceae, holds significant ethnobotanical value. Its lianas have traditionally been used as treatment for inflammatory and antiseptic purposes, stimulation of blood circulation, gout and rheumatism. In this study, one new stilbene derivative named montanumgam C (1) and six previously described compounds (2–7), were isolated from the ethyl acetate extract of the G. montanum lianas. The chemical structures of all isolated compounds were elucidated by extensive spectroscopic analysis, including 1D and 2D-NMR, ESI high-resolution mass spectrometry (HRESIMS), and comparison with reference data. All compounds exhibited xanthine oxidase (XO) inhibitory activity, with inhibition rates ranging from 5.4 to 90.4% at a concentration of 100 µM. Notably, compounds 1 and 3 showed potent inhibitory effect, with IC50 values of 18.8 and 13.7 µM, respectively, in comparison to a positive control, allopurinol (IC50 = 2.5 µM).