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

- Chenpi extract lowers lipid accumulation in differentiating adipocytes.
- Chenpi extract does not significantly affect mitotic clonal expansion.
- Chenpi extract does not significantly affect preadipocyte proliferation.
- Chenpi extract lowers expression of adipogenic regulators and lipogenic genes.
- 5-OH PMFs content contributes to the anti-lipogenic activity of chenpi extract.

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.