<p>This study focused on the extraction and purification process, structural characteristics and hypoglycemic mechanism of loquat seeds polysaccharide. The polysaccharides was extracted from loquat seeds by hot water and alcohol precipitation. The high purity polysaccharides was obtained by sevage, dialysis, diethylaminoethyl cellulose (DEAE-52) and SephadexG-100 column chromatography. Its structure was characterized by ultraviolet spectra (UV), infrared spectra (IR), ion chromatography, gel permeation chromatography, nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and the relative molecular weight, monosaccharide composition, glucoside bond type were determined. In terms of hypoglycemic activity in vitro, glucose oxidase method was used to accurately detect the glucose consumption of normal human hepatocellular carcinomas (HepG2) cells and insulin-resistant HepG2 cells, and cell viability was measured by cell counting kit 8 (CCK-8) method to evaluate the safety of polysaccharides on cells. In the study of hypoglycemic mechanism, the expression of key proteins in insulin signaling pathway was detected by immunofluorescence and western blot using insulin-resistant HepG2 cells as the model, and the effect of loquat seeds polysaccharide on insulin signaling was clarified. The results showed that the optimized extraction technology could significantly improve the yield of loquat seeds polysaccharide, and its unique chemical structure was identified by structural characterization. Functional experiments showed that loquat seeds polysaccharide could significantly improve the glucose consumption capacity of normal HepG2 cells and insulin-resistant HepG2 cells, and had no obvious adverse effects on cell viability in the concentration range of 40 ~ 640 µg/mL. At the same time, loquat seeds polysaccharide could up-regulate the expression of glucose transporter type 4 (GLUT4) in insulin signaling pathway, down-regulate the expression of glycogen synthase kinase-3β (GSK-3β) and insulin receptor substrate 1 (IRS1), activate insulin signaling, promote the translocation of glucose transporter GLUT4 to cell membrane, and enhance glucose transport in cells. In conclusion, loquat seeds polysaccharide has a good ability to regulate the hypoglycemic activity of insulin-resistant HepG2 cells, and its mechanism of action was mainly related to the activation of insulin signaling pathway, which provides a solid theoretical basis and technical support for the application of loquat seeds polysaccharide in the development of functional foods and hypoglycemic drugs.</p>

Hypoglycemic activity of loquat seeds polysaccharide in insulin resistant HepG2 cells

期刊论文
发表日期：

2025年9月1日

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Shiyang Zhou,
Jun Tan

摘要

This study focused on the extraction and purification process, structural characteristics and hypoglycemic mechanism of loquat seeds polysaccharide. The polysaccharides was extracted from loquat seeds by hot water and alcohol precipitation. The high purity polysaccharides was obtained by sevage, dialysis, diethylaminoethyl cellulose (DEAE-52) and SephadexG-100 column chromatography. Its structure was characterized by ultraviolet spectra (UV), infrared spectra (IR), ion chromatography, gel permeation chromatography, nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and the relative molecular weight, monosaccharide composition, glucoside bond type were determined. In terms of hypoglycemic activity in vitro, glucose oxidase method was used to accurately detect the glucose consumption of normal human hepatocellular carcinomas (HepG2) cells and insulin-resistant HepG2 cells, and cell viability was measured by cell counting kit 8 (CCK-8) method to evaluate the safety of polysaccharides on cells. In the study of hypoglycemic mechanism, the expression of key proteins in insulin signaling pathway was detected by immunofluorescence and western blot using insulin-resistant HepG2 cells as the model, and the effect of loquat seeds polysaccharide on insulin signaling was clarified. The results showed that the optimized extraction technology could significantly improve the yield of loquat seeds polysaccharide, and its unique chemical structure was identified by structural characterization. Functional experiments showed that loquat seeds polysaccharide could significantly improve the glucose consumption capacity of normal HepG2 cells and insulin-resistant HepG2 cells, and had no obvious adverse effects on cell viability in the concentration range of 40 ~ 640 µg/mL. At the same time, loquat seeds polysaccharide could up-regulate the expression of glucose transporter type 4 (GLUT4) in insulin signaling pathway, down-regulate the expression of glycogen synthase kinase-3β (GSK-3β) and insulin receptor substrate 1 (IRS1), activate insulin signaling, promote the translocation of glucose transporter GLUT4 to cell membrane, and enhance glucose transport in cells. In conclusion, loquat seeds polysaccharide has a good ability to regulate the hypoglycemic activity of insulin-resistant HepG2 cells, and its mechanism of action was mainly related to the activation of insulin signaling pathway, which provides a solid theoretical basis and technical support for the application of loquat seeds polysaccharide in the development of functional foods and hypoglycemic drugs.