Phospholipase A₂ Inhibitors from an <i>Erythrina</i> Species from Samoa

Abstract

Three flavonoid phospholipase A2 (PLA2) inhibitors were isolated from a MeOH extract of the bark of the Samoan medicinal plant Erythrina variegata. Two of these compounds, 4‘-hydroxy-3‘,5‘-diprenylisoflavonone (abyssinone V) (1) and 3,9-dihydroxy-2,10-diprenylpterocarp-6a-ene (erycrystagallin) (3), have been previously reported as antimicrobial agents from plants belonging to other Erythrina species. The isoflavonone 4‘-hydroxy-6,3‘,5‘-triprenylisoflavonone (2) is a new compound, and its structure was determined by spectroscopic techniques. The IC50 values for the PLA2 enzyme were 6, 10, and 3 μM for 1−3, respectively.