A new cycloartane triterpenoid from the n‐hexane extract of the lianas of <i>Gnetum montanum</i>

Abstract Gnetum montanum belongs to the Gnetaceae family. This plant's lianas have been traditionally used in Vietnam, India, Laos, and China to treat pain, rheumatism, arthritis, and bronchitis. By column chromatography and thin‐layer normal‐phase chromatography on the n ‐hexane extract of G. montanum lianas, a new secondary metabolite, montacylortan A ( 1 ), were isolated together with three known compounds including cycloeucalenol ( 2 ), epicycloeucalenone ( 3 ), and 24‐methylenecycloartanol ( 4 ). Interestingly, cycloeucalenol ( 2 ), epicycloeucalenone ( 3 ), and 24‐methylenecycloartanol ( 4 ) have not been isolated from G. montanum in the previous reports. The chemical structures of these compounds were determined through NMR spectroscopic analysis and validated by comparing them with previously published spectral data. Additionally, all isolated compounds were evaluated for their α‐glucosidase inhibitory activity. The results demonstrated that compounds 1–3 exhibited significant α‐glucosidase inhibitory activity, with IC50 values ranging from 23.57 to 79.31 µ m , which were more potent than that of a positive control, acarbose, which had the IC50 value of 185.2 µ m . Among them, montacylortan A (1) exhibited the most potent α‐glucosidase inhibitory activity with the IC50 value of 23.57 µ m , while cycloeucalenol ( 2 ) and epicycloeucalenone ( 3 ) had IC50 values of 79.31 and 45.90 µ m , respectively. These findings suggest that the isolated compounds from G. montanum have potential as α‐glucosidase inhibitors, which could be beneficial in managing conditions like diabetes.