Isolation and structural elucidation of new 8- <i>O</i> -4' neolignan and phenolic glucoside from the lianas of <i>gnetum montanum</i> markgr

In this study, the bioactivity guided by xanthine oxidase inhibition successfully isolated and characterised two new phenolic compounds named montanumgams A-B (<b>1</b>-<b>2</b>) together with fifteen known compounds (<b>3</b>-<b>17</b>) from the lianas of <i>Gnetum montanum</i> Markgr. Their chemical structures were elucidated by analysing nuclear magnetic resonance spectroscopy (1D and 2D-NMR), ESI high-resolution mass spectrometry (HRESIMS), and comparison with reference data. The activity of xanthine oxidase inhibition revealed that compound <b>1</b> has potent inhibitory effects, exhibiting IC₅₀ values of 16.6 µM, compared to a positive control, allopurinol (IC₅₀, 2.5 µM).