Effects of Yuzu (Citrus junos Siebold ex Tanaka) peel on the diet-induced obesity in a zebrafish model

Effects of yuzu peel (Citrus junos Siebold ex Tanaka), yuzu pomace after hexane extraction, and auraptene on metabolic disorders in zebrafish with diet-induced obesity (DIO) were evaluated. All materials tested exhibited anti-obesity effects. Yuzu peel significantly suppressed the rise in plasma triacylglycerol (TG) and liver lipid accumulation. The hepatic mRNA expression of pparab (peroxisome proliferator-activated receptor, alpha b) and its target genes were significantly upregulated by yuzu peel, which suggests enhanced fatty acid β-oxidation in liver. In visceral adipose tissue, yuzu peel significantly increased the mRNA expression of pparg (peroxisome proliferator-activated receptor, gamma) and adipoqb (adiponectin, C1Q and collagen domain containing, b), which play roles in adipose differentiation and maintenance. Our findings suggest that yuzu peel exerts anti-obesity effects by activating hepatic PPARα and adipocyte PPARγ pathways. Additionally, the anti-obesity effects of yuzu pomace suggest a novel application to achieve complete use of yuzu instead of disposal as industrial waste.