enrichment of polyphenolic compounds from grape leaf extract (vitis vinifera l.) using macroporous resin and investigating its adsorption kinetics and dynamics

Vitis vinifera l., with the common name grape, is native to mediterranean region and widely grown in different climatic conditions all over the world. grape leaves are also a rich source of important polyphenolic compounds that have been recognized for their diverse promising health benefits and therapeutic properties. in this study, the adsorption/desorption process on lxa-10 resin was investigated to enrich polyphenolic compounds in the prepared hydroalcoholic extract of grape leaves. the extract was obtained using ultrasound-assisted probe with water and ethanol (50:50) with an extraction yield of 26.4%. the ph value of the extract for maximum adsorption was optimized at 3.26. according to the findings of this study, the kinetic adsorption fitted well with pseudo-second-order model (r^2 = 0.99). moreover, the dynamic study revealed the adsorption capacity and required solvent for polyphenolic desorption being 42 ml and six-bed volume (bv), respectively. in the enriched powder, the amount of quercetin-3-o-glucuronide and quercetin-3-o-glucoside increased from the ranges of 19.43 to 45.92 mg.g^-1 and 41.244 to 72.88 mg.g^-1, respectively. the antioxidant activity of enriched polyphenols also increased from 252.37 in the initial grape extract to 408.03 mm iron (ii).mg^-1.