Comparison of In Vitro and In Vivo Antioxidant Activities of Six Flavonoids with Similar Structures.

Yixiu Zeng,Huayi Suo,Meimei Zhang,Hongwei Wang,Jiajia Song,Yu Zhang

doi:10.3390/antiox9080732

Abstract

The in vitro and in vivo antioxidant activities of six flavonoids with similar structures, including epicatechin (EC), epigallocatechin (EGC), procyanidin B2 (P), quercetin (Q), taxifolin (T), and rutin (R) were compared. The structures of the six flavonoids and their scavenging activities for 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radicals were closely related. The flavonoids decreased serum contents of malondialdehyde (MDA) and nitric oxide (NO), and increased serum total antioxidative capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) levels to different degrees in d-galactose-treated mice. The changes in mRNA expression of liver GSH-Px1, CAT, SOD1, and SOD2 by d-galactose were dissimilarly restored by the six flavonoids. Moreover, the six flavonoids differentially prevented the inflammatory response caused by oxidative stress by inhibiting interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α levels, and restoring IL-10 levels. These six flavonoids from two subclasses revealed the following antioxidant capability: P > EC, EGC > EC, Q > T, Q > R. Our results indicate that (1) the pyrogallol, dimerization, and C2=C3 double bonds of flavonoids enhanced antioxidant activity and (2) the C3 glycosylation of flavonoids attenuated antioxidant capacity.

Highlights

The aging process is accompanied by complex pathological changes, and aging is strongly related to a decline in physical function and an increased risk of death [1]
The in vitro antioxidant activities of the six flavonoids were estimated by measuring the clearance rates of DPPH and ABTS+ free radicals
We found that the orders of ability to scavenge DPPH radicals of the tested flavonoids were procyanidin B2 > epigallocatechin > quercetin > epicatechin ~ taxifolin >

Summary

Introduction

The aging process is accompanied by complex pathological changes, and aging is strongly related to a decline in physical function and an increased risk of death [1]. Aging is considered the primary driver in the development of human disease, and is one of the most important risk elements of stroke, neurodegenerative diseases, diabetes, and cancer [1,2]. The core feature of aging-related diseases is oxidative stress, as oxidative stress produces large amounts of reactive oxygen species (ROS) [3,4,5]. Seeking an effective antioxidant strategy is essential for anti-aging and treatment of aging-associated diseases. The side-effects of synthetic antioxidants have become increasingly prominent [7]; antioxidants from plants have gained increasing importance. The flavonoid extracted from mulberry fruit exhibits a strong antioxidant effect in vitro, and inhibits H2 O2 -induced hemolysis of mouse red blood cells and lipid peroxidation in the liver, mitochondria, and microsome of mice [8]

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