Anti-lipid droplets accumulation effect of Annona montana (mountain soursop) leaves extract on differentiation of preadipocytes

The Annona genus is a member of Annonaceae, one of the largest families of plants across tropical and sub-tropical regions. This family has been used in several ethnomedicinal practices to treat a multitude of human diseases. However, the molecular mechanism underlying its effect on the lipid droplet formation and on the expression of adipogenic markers of this plant remain to be investigated. In this study, we examined whether the extracts from the aerial part of Annona montana affect in vitro differentiation of preadipocytes. For our investigations, both mouse embryo fibroblast 3T3-L1 and normal human primary subcutaneous preadipocytes were incubated with Annona montana extracts (-and its subfractions-) and then analyzed on preadipocyte differentiation, lipid content, lipid droplet size and number, the expression of adipogenic-specific transcriptional factors, as well as cell survival. From our examinations, we found the Annona montana ethyl acetate extract to exhibit a potent inhibitory effect on adipogenesis, without affecting cell survival, in a dose-dependent manner. Such inhibitory effects included a significant decrease in the accumulation of lipid content by both a dramatic reduction of size and number of lipid droplets. This extract strongly attenuated the expression of PPARγ and HMGB2. It also inhibited the expression of CEBPα, FAS, and Akt without influencing Erk1/2 activities. Our findings suggest that specifically, the Annona montana ethyl acetate extract has a prominent inhibitory effect in cellular pathways of adipocyte differentiation by modulating specific gene expression, which is known to perform a pivotal role during adipogenesis.