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

Meiling Sun; Ying Wei; Xiaoguang Feng; Junfeng Fan; Xiangning Chen

doi:10.3389/fnut.2022.963858

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

Front Nutr. 2022 Sep 14:9:963858. doi: 10.3389/fnut.2022.963858. eCollection 2022.

Authors

Meiling Sun¹, Ying Wei¹, Xiaoguang Feng², Junfeng Fan³, Xiangning Chen¹

Affiliations

¹ Department of Food Science and Engineering, College of Food Science and Engineering, Beijing University of Agriculture, Beijing, China.
² Beijing Unong High-Quality Farm Products Planning Limited Company, Beijing, China.
³ Beijing Key Laboratory of Forest Food Processing and Safety, Department of Food Science and Engineering, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China.

Abstract

This study identified the constituents of purified flavonoid (PEF) isolated from Mesembryanthemum crystallinum and examined their inhibitory effects on low-density lipoprotein (LDL) oxidation and non-enzymatic glycosylation. More than 30 kinds of flavonoid compounds were identified in M. crystallinum, including tangeretin, nobiletin, farrerol, protocatechuic aldehyde, diosmin, and rutin. Moreover, tangeretin corresponds to approximately 51% of the total identified flavonoids. PEF had a low IC₅₀ value for 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH·), hydroxyl radical (·OH), and superoxide anion free radical (O $_{2}^{-} \cdot$ ) scavenging. They were found to effectively 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 effectively inhibited the production of LDL glycosylation products and showed a strong inhibitory effect in the latter stage. The electrophoresis of advanced glycosylation end products (AGEs) further confirmed that PEF can effectively prevent the cross-linking between glucose and proteins, protecting LDL from glycosylation-induced damage.

Keywords: UPLC-MS/MS; flavonoid compounds; low-density lipoprotein; non-enzymatic glycosylation; oxidation.