Kiwifruit Seed Polyphenols Ameliorate High-Fat-Induced Obese Mice via Inhibition of Inflammation and Regulation of Gut Microbiota Balance

Abstract

Kiwifruit seeds are a polyphenol‑rich by‑product of kiwifruit processing. This study evaluated the anti‑obesity effects of kiwifruit seed polyphenols (KSP) in C57BL/6 obese mice induced by high-fat diet (HFD). The results demonstrated that KSP attenuated body weight gain and adiposity in mice, improved glucose tolerance and insulin sensitivity, and reduced serum and hepatic triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and alanine aminotransferase (ALT)/aspartate aminotransferase (AST). Histology results confirmed KSP alleviated hepatic steatosis and adipocyte hypertrophy. In addition, KSP decreased interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in serum, liver, and colon; up-regulated UCP2 and PPAR-γ; and down-regulated SREBP-1c, FAS, and CPT-1a/b. KSP also reshaped gut microbiota by correcting the Firmicutes/Bacteroidetes imbalance, suppressing Proteobacteria, and enriching Bacteroides, Parabacteroides, Alistipes, and Alloprevotella, accompanied by the restoration of short-chain fatty acids, especially propionate. This study provides new evidence supporting KSP as a promising adjunct strategy for mitigating obesity and associated metabolic disorders through the gut-liver axis.