Triterpenoids from <i>Ganoderma angustisporum</i> and their <i>α</i> -glucosidase inhibitory activities

A novel triterpenoid, (22<i>S</i>, 24<i>E</i>)-3<i>β</i>, 15, 22-triacetoxy-6-oxolanosta-9, 24-dien-26-oic acid (<b>1</b>), together with eight previously identified analogues, was isolated from the solid-substrate culture of <i>Ganoderma angustisporum</i> J.H. Xing, B.K. Cui & Y.C. Dai. Their chemical structures were elucidated based on a comprehensive set of spectroscopic techniques, including 1D and 2D NMR as well as HRESIMS data. All obtained compounds were screened for <i>α</i>-glucosidase inhibitory activity. Compound <b>2</b> demonstrated potent inhibition (IC₅₀ = 18.26 ± 2.36 μM), exhibiting comparable activity to the positive control acarbose (IC₅₀ = 15.24 ± 2.63 μM). Molecular docking showed that compound <b>2</b> binds to the hydrophobic pocket of <i>α</i>-glucosidase by forming hydrogen bonds with Arg359, stabilising the complex with a binding energy of -7.2 kcal/mol.