Bio-guided fractionation and characterization of powerful antioxidant compounds from the halophyte Inula crithmoїdes

Abstract

The investigation of natural and safe antioxidants from natural origin is highly encouraged since it was revealed that synthetic antioxidants have restricted use in foods due to their toxicological effects and suspected carcinogenic potential. Purification of most active phenolics from the halophyte Inula crithmoїdes was the objective fixed for this work. The separation of the flower phenolics was carried using centrifugal partition chromatography (CPC) and yielded 24 fractions. A bio-guided selection of the most active fractions was done based on their antioxidant activities. Fractions 2, 7, 11 and 19 were the most active ones, even more potent than positive controls BHT, BHA and ascorbic acid. The semi-preparative High Performance Liquid Chromatography (HPLC) purification of the antioxidant molecules from these active fractions and their identification by Nuclear Magnetic Resonance spectroscopy (NMR) revealed that the most potent phenolics of I. crithmoїdes are the chlorogenic acid and its two derivatives 3-p-coumaroyl-5-caffeoyl quinic acid and 1,5-di-O-caffeoylquinic acid, in addition to the quercetin and its derivative quercimeritrin. All identified compounds are powerful antioxidants, as they have many biological properties allowing their use in agro-food, pharmaceutical or cosmetic industries.