Recovery of high yield flavonoids rich extract from two-phase Chemlali olive pomace

Abstract

Increasing interest in phenolic compounds in olive cake is due to their antioxidant and health-enhancing properties. In this study the flavonoids in two phase olive pomace of the Tunisian olive cultivar Chemlali were extracted by ethanol-water to obtain a flavonoid rich extract. The identification and quantification of flavonoids was based on separation by high-performance liquid chromatography equipped with a diode array detector followed by liquid chromatography-mass spectrometry analysis. Five flavonoids were isolated and purified using HPLC apparatus. Hesperidin and quercetin-3-O-arabinoglucoside were in high amount (15.60 and 21.71 mg/kg of fresh weight, respectively) followed by quercetin and luteolin (8.12 and 11.01 mg/kg of fresh weight, respectively). All purified flavonoids have been reported to possess as a natural antioxidants which was evaluated by measuring the radical scavenging effect on DPPH and by using ferric reducing antioxidant power assays. Bactericidal and fungicidal effects were shown using the NCCLS broth dilution. The minimal cidal concentrations (MCCs) values of ethyl acetate extract of TPCOP ranged from 1.825 to 14.6 mg/ml against tested pathogens and phytopathogens microbes. This activity was related to the richness of the extract of flavonoid compound especially quercetin-3-O-arabinoglucoside and hesperidin.