Phenolic profiles, antioxidant activities and cytoprotective effects of different phenolic fractions from oil palm (Elaeis guineensis Jacq.) fruits treated by ultra-high pressure.

The present work investigated the phenolic profiles, antioxidant activities, and cytoprotective effects of the free, esterified, and insoluble-bound phenolic fractions from oil palm fruits treated under ultra-high pressure (UHP). Results showed that UHP treatment significantly increased the total phenolic and flavonoid contents of all three phenolic fractions (p < 0.05). A total of 11 and 12 phenolic compounds were detected and quantified in non-treated and UHP-treated fruits, with caffeic acid having the highest concentration in insoluble-bound phenolic fractions with 8.68 and 11.27 mg/g of dry extract, respectively. The antioxidant activities, intracellular reactive oxygen species inhibition, and cytoprotective effects of all three phenolic fractions were dramatically enhanced after UHP pretreatment (p < 0.05). Therefore, UHP-treated oil palm fruits with increased bioactivities could be used in functional food or the nutraceutical industry to enhance their applications and economic value.