Passion fruit peel pectin improves glucose and lipid metabolism in high-fat diet-induced obesity through gut microbiota and insulin sensitivity regulation

This study investigated the effects of passion fruit peel pectin (PFP) on glucose and lipid metabolism in mice fed a high-fat diet (HFD). Fifty mice were divided into five groups: (1) normal diet (ND), (2) HFD, (3) HFD with orlistat (20 mg/kg/day, positive control, PC-HFD), (4) HFD with 300 mg/kg/day PFP (PFP1), and (5) HFD with 600 mg/kg/day PFP (PFP2) for 8 weeks. Compared to HFD, both PFP1 and PFP2 groups exhibited significant reductions in body weight (−3.9 % and −4.4 %), serum glucose (−17.6 % and −20.4 %), and hepatic lipid accumulation (−68.6 % and −65.2 % in oil red O-stained area). 16S rRNA analysis showed that PFP increased SCFA-producing gut bacteria. Tax4Fun2 analysis predicted enrichment of microbial functional potential related to the host insulin resistance pathway in PFP-treated mice. Fecal metabolomics and SCFA analyses revealed increased levels of pyruvic acid, triglycerides, and acetic acid in feces. Liver transcriptomics showed enrichment of 7 genes in the insulin resistance pathway. Integrated analyses of 16S rRNA and multi-omics data suggested associations between PFP intervention and modulation of pathways related to insulin resistance and hepatic lipid metabolism. qRT-PCR analysis demonstrated that PFP increased the mRNA expression of PI3K, AKT, INSR, IRS1, and GLUT4, while decreasing G6P expression. These findings suggest that PFP might improve certain aspects of metabolic dysregulation in HFD-fed mice, potentially through modulation of insulin sensitivity and hepatic lipid handling.