Determining antioxidant activities of lactobacilli cell-free supernatants by cellular antioxidant assay: a comparison with traditional methods.

Hao Zhang,Qiuxiang Zhang,Yong Q. Chen,Wei Chen,Xiaoming Liu,Jiali Xing,Gang Wang,Zhennan Gu

doi:10.1371/journal.pone.0119058

Abstract

Antioxidant activity of lactic acid bacteria is associated with multiple health-protective effects. Traditional indexes of chemical antioxidant activities poorly reflect the antioxidant effects of these bacteria in vivo. Cellular antioxidant activity (CAA) assay was used in this study to determine the antioxidant activity of cell-free supernatants (CFSs) of 10 Lactobacillus strains. The performance of the CAA assay was compared with that of four chemical antioxidant activity assays, namely, DPPH radical scavenging, hydroxyl radical scavenging (HRS), reducing power (RP), and inhibition of linoleic acid peroxidation (ILAP). Results of the CAA assay were associated with those of DPPH and ILAP assays, but not with those of RP and HRS assays. The inter- and intra-specific antioxidant activities of CFS were characterized by chemical and CAA assays. L. rhamnosus CCFM 1107 displayed a high antioxidative effect similar to positive control L. rhamnosus GG ATCC 53103 in all of the assays. The CAA assay is a potential method for the detection of antioxidant activities of lactobacilli CFSs.

Highlights

Increasing scientific evidence suggests that oxidative stress is involved in the pathogenesis of various disorders and diseases, such as alcohol-induced liver injury, non-alcoholic fatty liver disease, ageing, and cancer [1,2,3,4]
Results of two radical scavenging methods (i.e., hydroxyl radical scavenging (HRS) and DPPH) showed that the 10 lactobacilli cell-free supernatants (CFSs) can inhibit the formation of the two radicals (Fig. 1)
This study shows that lactobacilli CFSs exhibit antioxidant activities (AAs) that can be assessed quantitatively in HepG2 cells

Summary

Introduction

Increasing scientific evidence suggests that oxidative stress is involved in the pathogenesis of various disorders and diseases, such as alcohol-induced liver injury, non-alcoholic fatty liver disease, ageing, and cancer [1,2,3,4]. Oxidative stress is a result of an imbalance between production and elimination of reactive oxygen species (ROS) and free radicals, which are primarily removed by the endogenous antioxidant defense system [5]. Consumption of antioxidants, which can quench free radicals and ROS, may be beneficial to human health. Synthetic antioxidants are effective in slowing oxidation, but pose concerns in regard to the safety and toxicity of the antioxidants [6,7].

Methods

Results

Conclusion