Anacardic acid derivatives with significant α-glucosidase inhibitory activity from Syzygium samarangense

Our continuous effort to search for antidiabetic constituents from the leaves of Syzygium samarangense resulted in the isolation of one new anacardic acid derivative, 2-[(Z)-nonadec-14-enyl]-6-hydroxylbenzoic acid (1) along with four known analogues (2−5). The new structure was elucidated by means of extensive spectroscopic data including 1D and 2D NMR along with HRESIMS. The anacardic acid derivatives were isolated from this species for the first time. All compounds exhibited significant inhibitory effect with IC50 value of 0.75−3.60 μM against α-glucosidase.