Antiobesity effects of kimchi added with Jeju citrus concentrate on high-fat diet-induced obese mice

Citrus fruits contain an abundance of nutrients, including vitamins C and B₆ and hesperidin, which attribute to its beneficial health effects. Previously, kimchi with Jeju citrus concentrate (CK) elicited anti-obesity effects in 3T3-L1 adipocytes. Here, we aimed to investigate whether CK exhibits anti-obesity effects by reducing serum and hepatic lipid concentrations and anti-obesity-associated gene expression in high-fat diet (HFD)-induced obese C57BL/6N mice. Low-dose CK (LDCK, 50 mg/kg) and high-dose CK (HDCK, 200 mg/kg) were orally administered 3 times per week over 8 weeks with HFD diet. Body weight gain, food efficiency ratio, and tissue weight were measured. Serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, fasting glucose, fasting insulin, homeostatic model assessment-insulin resistance, leptin, and adiponectin concentrations were also assessed. The effect of CK on the lipid profile and lipid accumulation was analyzed. Body and white adipose tissue masses were significantly lower in the LDCK and HDCK groups than in the HFD group. Orally administered CK significantly decreased serum lipid, fasting glucose, fasting insulin, homeostatic model assessment-insulin resistance, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase levels. Hepatic lipid content also decreased in the LDCK and HDCK groups. Serum leptin concentrations decreased, whereas serum adiponectin concentrations increased, confirming the anti-obesity effects of LDCK and HDCK. The decrease of hepatic vacuoles and stained lipid droplets indicated inhibition of lipid accumulation. These results support the hypothesis that CK exhibits anti-obesity effects in vivo by reducing lipid accumulation and by regulating anti-obesity-related genes.