Effect of Indian gooseberry extract on improving methylglyoxal-associated leptin resistance in peripheral tissues of high-fat diet-fed rats

Sheng-Yi Chen ^a,1, Yue-Ning Huang ^a,1, Jer-An Lin ^b, Gow-Chin Yen ^a,*

^a Department of Food Science and Biotechnology, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan

^b Graduate Institute of Food Safety, National Chung Hsing University, 145 Xingda Road, Taichung 40227, Taiwan

Increased leptin resistance and methylglyoxal (MG) levels are observed in obese patients. However, whether MG deposits contribute to leptin resistance, oxidative stress, and inflammation in peripheral tissues remains unclear. In addition, the edible fruit of Indian gooseberry (Phyllanthus emblica L.) contains abundant bioactive components such as vitamin C, β-glucogallin (β-glu), gallic acid (GA), and ellagic acid (EA). Water extract of Indian gooseberry fruit (WEIG) and GA has been shown to improve cognitive decline by suppressing brain MG-induced insulin resistance in rats administered a high-fat diet (HFD). Accordingly, this study investigated the functions of WEIG and GA in inhibiting MG-induced leptin resistance, oxidative stress, and inflammation in the peripheral tissues of HFD-fed rats. The results showed that MG, advanced glycation end products (AGEs), and leptin resistance accumulation in the liver, kidney, and perinephric fat were effectively restored by elevated glyoxalase-1 (Glo-1) activity after WEIG and GA administration comparable to that of alagebrium chloride (positive control) treatment in HFD-fed rats. Furthermore, WEIG and GA supplementation increased adiponectin and antioxidant enzymes (glutathione peroxidase, superoxide dismutase, catalase) and decreased inflammatory cytokines (IL-6, IL-1β, TNF-α) in the peripheral tissues of HFD-fed rats. In conclusion, these findings demonstrated that MG may trigger leptin resistance, oxidative stress, and inflammation in peripheral tissues, which could be abolished by WEIG and GA treatment. These results show the potential of P. emblica for functional food development and improving obesity-associated metabolic disorders.

Keywords: Adiponectin, Gallic acid, Glyoxalase-1, Methylglyoxal, WEIG

https://doi.org/10.38212/2224-6614.3494