Isomeric Polycyclic Polyprenylated Acylphloroglucinols from the Bark of Mesua ferrea (Clusiaceae)

Five new isomeric polycyclic polyprenylated acylphloroglucinols (PPAPs) named mesuaferroic acid A, B, C, E and F (1–5) were isolated from ethyl acetate extract of Mesua ferrea L. (Clusiaceae). The isomeric compounds were obtained after extensive chromatographic procedures mainly using preparative HPLC. Structures were established after detailed spectroscopic analysis mostly by 2D NMR techniques. Compounds 4 and 5 exhibited good α-glucosidase inhibitory activity with IC50 values of 0.43 and 0.60 mM, respectively, comparing to the positive control, 1-deoxynojirimycin (IC50 0.63 mM).