Assay of phenolic compounds from four species of ber (Ziziphus mauritiana L.) fruits: Comparison of three base hydrolysis procedure for quantification of total phenolic acids

The present study was undertaken to investigate the flavonoid profile in four species of ber (Ziziphus mauritiana Lamk.) fruit. The 12 flavonoids identified were quercetin 3-O-robinobioside, quercetin 3-O-rutinoside, quercetin 3′-O-galactoside, quercetin 3′-O-glucoside, quercetin 3′-O-rhamnoside, quercetin 3′-O-pentosylhexoside, quercetin 3-O-6′malonylglucoside, quercetin 3′-O-malonylglucoside, luteolin 7-O-6′malonylglucoside, luteolin 7-O-malonylglucoside, myricetin 3-O-galactoside, and naringenin tri glycoside. This is the first report on extraction of nine additional flavonoids from the ber fruits. In addition, we also compared the impact of three different base hydrolysis techniques namely ultrasonic assisted base hydrolysis (UABH), microwave assisted base hydrolysis (MWABH), and pressurised liquid assisted base hydrolysis (PLABH) for the quantification of total phenolic acids. Nine phenolic acids, protocatechuic acid, p-hydroxybenzoic acid, ferulic acid, chlorogenic acid, vanillic acid, caffeic acid, vanillin, ortho- and para-coumaric acids, were identified and quantified. The three major phenolic acids identified in all four ber species were p-coumaric acid, vanillin and ferulic acids. Higher amounts (p < 0.05) of total phenolic acids in all cultivars were obtained with the PLABH technique as compared to other two procedures (UABH and MWABH).