Polyphenol-Rich Extract of Fermented Chili Pepper Alleviates Insulin Resistance in HepG2 Cells via Regulating INSR, PTP1B, PPAR-γ, and AMPK Pathways

Abstract

Fermented Capsicum frutescens L. is a well-known traditional food ingredient in China with a variety of potential nutritional functions due to the increased content of polyphenolic compounds during the fermentation process. This study aimed to investigate the ameliorative effect of fermented chili peppers (FCP) on insulin resistance and the potential mechanism of action. HepG2 cells were treated with 5 × 10−6 mol/L insulin for 12 h to establish the insulin resistance model. The results showed that the ethanol extract of FCP (1 mg/mL), rather than non-FCP extract, significantly increased glucose consumption in insulin-resistant HepG2 cells, which was at least partly attributed to an increase in polyphenolic compounds after fermentation, including kaempferol-3-O-rutinoside, caffeic acid, kaempferol-3-O-glucoside, luteolin, and apigenin. Molecular docking analysis suggested that these five significantly increased polyphenolic compounds in FCP could partially and effectively interact with the key amino acid residues of four key insulin resistance-related receptors (INSR, PTP1B, PPAR-γ, and AMPK). In conclusion, the fermentation process enhanced or even conferred a pronounced anti-insulin resistance effect on chili peppers, and the increased polyphenolic compounds in chili pepper had synergistic effects in modulating the INSR, PTP1B, PPAR-γ, and AMPK pathways to regulate the destruction of glucose consumption.

Unraveling the Genetic Adaptations in Cell Surface Composition and Transporters of Lactiplantibacillus plantarum for Enhanced Acid Tolerance

“…Yunnan Province, located in southern China, has diverse climatic and geographic conditions that create biodiversity and a unique ecological microenvironment for fermented vegetables from this region . Our previous studies have elucidated the fermentation process, flavor, and nutritional functions of fermented vegetables such as chili pepper and chayote from Yunnan Province. − However, the rich microbial resources in Yunnan Province have not been fully exploited, and there is a lack of standardized production …”

The Genus Capsicum: A Review of Bioactive Properties of Its Polyphenolic and Capsaicinoid Composition

“…In this regard, it is important to note that certain strains of LAB and yeast, during fermentation, can metabolize phenolic acids and thus increase their bioactivity or bioavailability [ 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 ]. This can lead to an increase in antioxidant, anti-inflammatory and antiglycemic activity, among others [ 146 , 147 , 148 ]. Therefore, studies on the effect of fermentation with LAB or yeast strains on the concentration of polyphenols, as well as on the bioactive effects due to the microbial transformation of these compounds, will be of great scientific importance.…”