Inhibitory effects of compounds isolated from the dried branches and leaves of murta (Myrceugenia euosma) on lipid accumulation in 3T3-L1 cells.

As obesity is a global health concern the demand for anti-obesity drugs is high. In this study, we investigated the anti-obesity effect of the dried branches and leaves of murta (Myrceugenia euosma Legrand, Myrtaceae). A methanol extract of the dried branches and leaves of murta inhibited adipogenesis in 3T3-L1 cells. Three known flavanones-cryptostrobin (1), pinocembrin (4), and 5,7-dihydroxy-6,8-dimethylflavanone (6), and three chalcones-2',6'-dihydroxy-3'-methyl-4'-methoxychalcone (2), pinostrobin chalcone (3), and 2',6'-dihydroxy-4'-methoxy-3',5'-dimethylchalcone (5) were isolated from the active fraction. Structures of these compounds were identified using various spectral data. Each of these compounds also inhibited adipogenesis in 3T3-L1 cells. In particular, compound 3 was a more potent inhibitor of triglyceride accumulation than the positive control berberine. Gene expression studies revealed that treatment of 3T3-L1 cells with 3 lowers the expression levels of CCAAT/enhancer-binding protein α and peroxisome proliferator activator γ2 during adipogenesis without affecting cell viability. Treatment of 3T3-L1 cells with 3 reduced the expression levels of mRNAs encoding sterol regulatory element-binding protein 1c and several lipogenic enzymes, including fatty acid synthase and stearoyl CoA desaturase-1. These results indicate that the methanol extract and compounds isolated from the dried branches and leaves of murta exert their anti-obesity effects through the inhibition of adipogenesis.