THE INFLUENCE OF THE HARVESTING MATURITY ON POLYPHENOL COMPOSITION AND ANTI-DIABETIC PROPERTIES OF HASKAP BERRIES (Lonicera caerulea L.)

Abstract

Haskap (Lonicera caerulea L.) is a recently commercialized crop in Canada. Berries of four cultivars, Aurora, Rebecca, Larissa, and Evie, were harvested at five harvesting dates (H1-H5) and assessed for their polyphenol composition, antioxidant capacity, and anti-diabetic properties. The analyses revealed that the interaction effect of cultivar and harvesting date influenced the anthocyanins. Moreover, Larissa and Evie at H5 showed the significantly higher C3G content. Extracts derived from five maturity stages of four cultivars showed anti-diabetic properties including inhibition of activities of alpha-amylase, alpha-glucosidase, dipeptidyl peptidase-4, and formation of advanced glycation end-products in vitro. Dietary supplementation of C3G-rich haskap extract (CE) in mice fed with high-fat high-sucrose diet reduced the rate of weight gain, an improved glucose tolerance, and suppressed in gluconeogenesis regulating protein, fructose-1,6-bisphosphatase with concomitantly increased phosphorylation of 5' AMP-activated protein kinase (AMPK). In conclusion, C3G may improve the plasma glucose profile in diet-induced obesity by decreasing gluconeogenesis