Inhibitory effects of flavonoids from Abelmoschus manihot flowers on triglyceride accumulation in 3T3-L1 adipocytes

The 95% EtOH extract from the flowers of Abelmoschus manihot (L.) Medic showed inhibitory activity on TG accumulation in 3T3-L1 preadipocyte. Chemical studies on the active fraction led to the isolation of 14 Flavonoids (1-14). To clarify the multi-mechanism of the isolates on preadipocyte differentiation, the levels of TG and FFA and the related role transcription factors (PPARγ, CEBP/α, and ap2) expression were evaluated. At the concentration of 30 μM, compounds 1-6 and 10-14 showed inhibitory activity on TG accumulation significantly in mature 3T3-L1 cells. 1, 2, 4-7, 9, 10, 13, and 14 reduced the level of FFA. At the molecular level, the mRNA expressions of PPARγ, CEBP/α, and ap2 were down-regulated by compounds 1, 5, 9, 12, 13; 1-8, 10-14; and 1-4, 6, 8-12, 14, respectively. The structure-activity relationships of the 14 Flavonoids were also discussed.