Bioguided chemical characterization of pequi (Caryocar brasiliense) fruit peels towards an anti-diabetic activity

Pequi fruit peels are an underexploited source of polyphenols. The anti-diabetic potential of an extract and fractions from the peels were evaluated in a panel of assays. The extract and fractions thereof inhibited the release of cytokines involved in insulin resistance - TNF, IL-1 beta, and CCL2 - by lipopolysaccharide-stimulated THP-1 cells. The ethyl acetate fraction inhibited in vitro alpha-glucosidase (pIC(50) = 4.8 +/- 0.1), an enzyme involved in the metabolization of starch and disaccharides to glucose, whereas a fraction enriched in tannins (16C) induced a more potent alpha-glucosidase inhibition (pIC(50) = 5.3 +/- 0.1). In the starch tolerance test in mice, fraction 16C reduced blood glucose level (181 +/- 10 mg/dL) in comparison to the vehicle-treated group (238 +/- 11 mg/dL). UPLC-DAD-ESI-MS/MS analyses disclosed phenolic acids and tannins as constituents, including corilagin and geraniin. These results highlight the potential of pequi fruit peels for developing functional foods to manage type-2 diabetes.

Automated summary

Pequi fruit peels contain polyphenols that exhibit anti-diabetic potential by inhibiting cytokines involved in insulin resistance and α-glucosidase activity, reducing blood glucose levels in mice. The presence of phenolic acids and tannins in the peels highlights their potential for developing functional foods to manage type-2 diabetes.