Aged citrus peel (chenpi) extract reduces lipogenesis in differentiating 3T3-L1 adipocytes

Abstract Aged citrus peel ( chenpi ) is made from the dry peel of the fruit of Citrus reticulate Blanco after aging process. It has long been used as a food ingredient, a dietary supplement, and for medicinal purpose. Compared to fresh citrus peel extract, chenpi extract contains more 5-demethylated polymethoxyflavones (5-OH PMFs). To investigate a potential direct role of chenpi extract on adipose tissue, we examined the effect of chenpi extract on differentiating 3T3-L1 cells. We showed that two types of chenpi extract varying in 5-OH PMF contents consistently reduces intracellular lipid accumulation without significantly affecting cell viability and proliferation. The reduction in lipid accumulation is correlated with AMP-activated protein kinase (AMPK) activation and down-regulation of adipogenic transcription factors as well as lipogenic genes. The results indicate that chenpi extract may directly affect lipogenesis in adipose tissue and the content of 5-OH PMFs likely affects the anti-lipogenic activity of chenpi extract.