Antioxidant triterpenoids from the stems of Momordica charantia

A new multiflorane triterpenoid and two new cucurbitane triterpenoids were isolated from the stems of Momordica charantia. The structures of the new compounds were elucidated by spectroscopic methods. These three new compounds, 1, 2 and 3 displayed ABTS radical cation scavenging activity with IC50 values of 268.5 ± 7.9, 352.1 ± 11.5 and 458.9 ± 13.0 μM, respectively and an inhibitory effect on xanthine oxidase (XO) activity with IC50 values of 142.3 ± 30.2, 36.8 ± 20.5 and 124.9 ± 8.3 μM, respectively. This finding indicated that 1–3 can be used as antioxidants.