Consumption of guava may have beneficial effects in type 2 diabetes: A bioactive perspective

The objectives of this study were to evaluate the anti-diabetic and anti-hyperlipidemic effects and relative mechanisms of guava polysaccharides (GPs) in rats with type 2 diabetic mellitus (T2DM). The chemical characterization and monosaccharide compositions of GPs, named as GP-1, GP-2, GP-3, and GP-4, were determined by PMP-HPLC and FT-IR. The results revealed that all GPs had the typical saccharide absorptions, and all were heteropolysaccharides. In addition, GPs efficiently decreased levels of fasting blood glucose, glucosylated serum protein, serum insulin, homeostasis model assessment of insulin resistance, total cholesterol, triglyceride and serum alanine transaminase, improved oral glucose tolerance, and increased insulin sensitivity in rats with T2DM. Histopathological observations suggested that GP-1, GP-3, and GP-4 could alleviate injury in pancreatic islet cells, and Western blot analysis showed that these GPs upregulated gene expression of the insulin receptor, insulin receptor substrate 2, Akt, and glucose transporter type 4. Taken together, these data suggest that GPs may be beneficial in treating T2DM and reducing the risk of hyperlipidemia, vascular disease, and cirrhosis via the PI3K/Akt signaling pathway.