Contents, profiles and bioactive properties of free and bound phenolics extracted from selected fruits of the Oleaceae and Solanaceae families

This study of selected fruits of the Oleaceae and Solanaceae families quantified the contents of free and bound phenolics (FP and BP) and their in vitro antioxidant activity and inhibitory potential towards enzymes relevant for hypertension and hyperglycemia management. For all the fruits considered, FP extracted at 30 °C (FP-30 °C) were the predominant fraction of the total phenolics and had higher antioxidant activities. The highest inhibition (100%) towards angiotensin I-converting enzyme (ACE), α-amylase and α-glucosidase was obtained respectively with extracts from tomato (FP-30 °C extract) and red pickled olive (BP-acid extract), red hot pepper (BP-base extract), and green and red pickled olives and yellow sweet pepper (BP-base extracts). Significant positive correlations existed between ACE inhibitory activity and total phenolics for Solanaceae fruits, and between the α-amylase and α-glucosidase inhibitory activities of phenolics from olives, tomato and yellow sweet pepper. Distinct phenolic profiles were evidenced for each fruit, with p-coumaric acid detected in appreciable amounts in BP extracts from all fruits.