Citral, a Monoterpene Inhibits Adipogenesis Through Modulation of Adipogenic Transcription Factors in 3T3-L1 Cells

Abstract

Obesity is considered as a major global human health problem which significantly increases the risk for development of type 2 diabetes. Citral, a bioactive compound widely found in a variety of foods that are consumed daily. In this study, we investigated the inhibitory effect of citral against adipogenic genes in 3T3-L1 cells. The mouse fibroblast 3T3-L1 pre-adipocytes were differentiated into adipocytes using adipogenic cocktail (5g/ml insulin, 0.5mM isobutylmethylxanthine and 10M dexamethasone). Differentiation of adipocytes was evaluated by assessing triglyceride accumulation assay and cell viability by MTT assay. The PI3K/AKT signaling, adipogenic specific transcription factors (PPARγ, SREBP-1c, FAS and CPD) and inflammatory genes (TNF-α, IL-6 and MCP-1) were analyzed by western blotting and reverse transcriptase PCR in differentiated 3T3-L1 cell lines. In this study, triglyceride accumulation was increased in adipogenic cocktail induced 3T3-L1 cells, whereas treatment of citral significantly decreased levels of triglyceride accumulation in concentration dependent manner. Further, MTT assay shows that there was no reduction of cell viability during the differentiation of 3T3-L1 cells. The differentiated 3T3-L1 cell significantly increases the expression of PI3K/AKT, adipogenic transcription factors (PPARγ, SREBP-1c, FAS and CPD) and inflammatory biomarkers (TNF-α, IL-6 and MCP-1). Conversely, cells were treated with citral significantly suppress the expression of PI3K/AKT, PPARγ, SREBP-1c, FAS, CPD, TNF-α, IL-6 and MCP-1 in dose dependent manner. Thus, citral exhibits beneficial effects to inhibit adipogenesis in 3T3-L1 adipocytes through the modulation of adipogenic transcription factors and inflammatory markers.