Analytical Profiling of Proanthocyanidins from Acacia mearnsii Bark and In Vitro Assessment of Antioxidant and Antidiabetic Potential.

Shenlin Huang,Fei Wang,Jia Xiong,Xiao Chen,Yu Zhang,Liping Zhang,Xun Li

doi:10.3390/molecules23112891

Abstract

The proanthocyanidins from ethanol extracts (80%, v/v) of Acacia mearnsii (A. mearnsii) bark on chemical-based and cellular antioxidant activity assays as well as carbolytic enzyme inhibitory activities were studied. About 77% of oligomeric proanthocyanidins in ethanol extracts of A. mearnsii bark were found by using normal-phase HPLC. In addition, HPLC-ESI-TOF/MS and MALDI-TOF/TOF MS analyses indicated that proanthocyanidins from A. mearnsii bark exhibited with a degree of polymerization ranging from 1 to 11. These results of combined antioxidant activity assays, as well as carbolytic enzyme inhibitory activities of proanthocyanidins from A. mearnsii bark, indicated an encouraging antioxidant capacity for the high polyphenol content and a potential for use as alternative drugs for lowering the glycemic response.

Highlights

Proanthocyanidins (PAs), a family of plant polyphenols, are secondary metabolites of plants, which are important for plant growth and protection against infection and injury [1]
The Trolox equivalent antioxidant capacity (TEAC) values were used in DPPH, ABTS, and Oxygen Radical Absorbance Capacity (ORAC) assays, calculated as mg Trolox equivalent (TE)/g dried extract
About 77% of oligomers and PAs with molecular weight (MW) ranging from 290 Da to 3300 Da in ethanol extracts of A. mearnsii bark were firstly identified

Summary

Introduction

Proanthocyanidins (PAs), a family of plant polyphenols, are secondary metabolites of plants, which are important for plant growth and protection against infection and injury [1]. Different types of PAs exist based on the substitution pattern of monomeric flavan-3-ol units linked by a single. C4 –C8 or C4 –C6 bond (B-type PAs) or by an additional C2 –O–C7 or C2 –O–C5 bond (A-type PAs) [2]. They are widely distributed in plant resources, usually comprising procyanidins, prodelphinidins, and propelargonidins, which consist of (epi)catechin, (epi)gallocatechin, and (epi)afzelechin units, respectively [3,4]. Many researchers have studied their health benefits [7,8] They have been reported to exert notable pharmacological effects, including antioxidative, antimicrobial, antiproliferative, enzyme inhibitory, and cardioprotective effects [5,9]. Smaller PAs are more effective as superoxide anion scavengers, free-radical scavengers, and xanthine oxidase inhibitors than larger PAs, Molecules 2018, 23, 2891; doi:10.3390/molecules23112891 www.mdpi.com/journal/molecules

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