A new cucurbitane - type triterpenoid from the bark of Elaeocarpus hygrophilus Kurz

A new cucurbitacin, 3β-(β-D-glucopyranosyloxy)-5β,6β:16α,23α-diepoxycucurbit-24-en-11-one or hygrocucurbin A (1), along with two known compounds, including 3β-(β-D-glucopyranosyloxy)-16α,23α-epoxycucurbita-5,24-dien-11-one (2) and (+)-lyoniresinol (3), were isolated from the bark of Elaeocarpus hygrophilus. Their chemical structures were elucidated by spectroscopic NMR, HR-IDA- TOF-MS analysis, and by comparison with the spectral data of corresponding compounds in the literature. Two cucurbitacins (1) and (2) were evaluated for their α-glucosidase inhibitory activity and cytotoxic against KB, MCF-7, Hep G2, and A549 cancer cell lines. For the α-glucosidase inhibitory activity, compound 1 showed an equivalent effect (IC₅₀ 197.4 ± 4.1 µM) compared to the acarbose, a positive control (IC₅₀ 208.5 ± 4.7 µM). And for the cytotoxicity, 2 was inactive while 1 was slightly sensitive against KB cells (IC₅₀ 233.3 ± 2.5 µM).