Citrus depressa peel extract acts as a prebiotic to reduce lipid accumulation and modulate gut microbiota in obese mice

Zheng-Yuan Su^a, Jie-An Liao^a, Ching-Ting Lin^a, Guor-Jien Wei^b, Yen-Chen Tung^c*

^a Department of Bioscience Technology, Chung Yuan Christian University, Taoyuan City 320314, Taiwan

^b Institute of Food Safety and Health Risk Assessment, National Yang Ming

Chiao Tung University, Taipei, 112304, Taiwan

^c Department of Food Science, National Ilan University, Yilan County 260007, Taiwan

Citrus peels contain abundant polyphenols, particularly flavonoids, and have been shown to exert lipid accumulation decreasing ability. In this study, Citrus depressa peel applied to oven drying and extracted with ethanol extract as CDEE to analyze its flavonoids compositions and investigated its effects on a high-fat diet (HFD)-induced obese mice model. CDEE contained several flavonoids such as hesperidin, sinesentin, nobiletin, tangeretin, 5-demethylnobiletin, and 5-demethyltangeretin. The mice fed an HFD, and administration of 2% CDEE to could decrease weight gain, abdominal fat weight, inguinal fat weight, and the adipocyte size, and CDEE also reduced serum total cholesterol (TCHO), triacylglycerol (TG) compared with mice fed only on HFD. CDEE hindered lipid accumulation through a decreased fatty acid synthase (FAS) protein expression via upregulation of the protein expression of AMP-activated protein kinase α (AMPKα). Moreover, CDEE modulated gut microbiota that altered by HFD through an increased abundance of Lactobacillus reuteri compared with the HFD group. The results demonstrated that CDEE helps decrease lipid accumulation through the AMPK pathway, which also indicates a prebiotic-like effect on gut microbiota.