Composition, anti-LDL oxidation, and non-enzymatic glycosylation inhibitory activities of the flavonoids from Mesembryanthemum crystallinum

Abstract

This study identified the constituents of purified flavonoid (PEF) isolated from Mesembryanthemum crystallinum and examined their inhibitory e ects on low-density lipoprotein (LDL) oxidation and non-enzymatic glycosylation. More than kinds of flavonoid compounds were identified in M. crystallinum, including tangeretin, nobiletin, farrerol, protocatechuic aldehyde, diosmin, and rutin. Moreover, tangeretin corresponds to approximately % of the total identified flavonoids. PEF had a low IC value for , -diphenyl--picrylhydrazyl radicals (DPPH•), hydroxyl radical (•OH), and superoxide anion free radical (O − •) scavenging. They were found to e ectively delay and inhibit the production of conjugated diene (CD) and thiobarbituric acid reactive substance (TBARS) during LDL oxidation. Meanwhile, scanning electron microscopy (SEM) of the LDL oxidation incubation system with PEF showed a smooth and dense surface, with no obvious cavitation phenomenon. Furthermore, PEF e ectively inhibited the production of LDL glycosylation products and showed a strong inhibitory e ect in the latter stage. The electrophoresis of advanced glycosylation end products (AGEs) further confirmed that PEF can e ectively prevent the cross-linking between glucose and proteins, protecting LDL from glycosylation-induced damage.