Flavokawains, Plant-derived Chalcones, Inhibit Differentiation of Murine Pre-adipocytes

Abstract

Efforts to isolate compounds from an Indonesian member of the ginger family, Kaempferia angustifolia, yielded three known molecules, identified as (+)-crotepoxide (1), (+)-pipoxide chlorohydrin (2), and flavokawain A (FKA, 3). All three compounds strongly inhibited triglyceride accumulation in 3T3-L1 murine pre-adipocytes at 10 g/mL, and compounds 1 and 2 were both cytotoxic at this concentration. To determine the biological activities of natural 3, flavokawains A (3), B (4) and C (5) were synthesized. While 4 was cytotoxic, both 3 and 5 potently inhibited differentiation of murine pre-adipocytes and reduced triglyceride accumulation (EC50 = 64.4 and 26.1 M, respectively) with relatively weak cytotoxicity. Thus, the electron-donating group on the aromatic B ring may contribute to the highly selective anti-obesity activity.