Elsevier

Food Chemistry

Volume 135, Issue 3, 1 December 2012, Pages 1914-1919
Food Chemistry

Antioxidant activity of Lactobacillus plantarum strains isolated from traditional Chinese fermented foods

https://doi.org/10.1016/j.foodchem.2012.06.048Get rights and content

Abstract

Eleven Lactobacillus plantarum strains isolated from traditional Chinese fermented foods were investigated for their in vitro scavenging activity against hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals, and their resistance to hydrogen peroxide. L. plantarum C88 at a dose of 1010 CFU/ml showed the highest hydroxyl radical and DPPH scavenging activities, with inhibition rates of 44.31% and 53.05%, respectively. Resistance of intact cells to hydrogen peroxide was also found in all strains. L. plantarum C88 was the most resistant strain against hydrogen peroxide. When L. plantarum C88 was administered to senescent mice suffering oxidative stress induced by d-galactose, the serum superoxide dismutase activity, the glutathione peroxidase activity and the total antioxidant capacity in liver increased significantly, while the level of malondialdehyde in liver decreased significantly. L. plantarum C88 isolated from traditional Chinese fermented dairy tofu could be considered as a potential antioxidant to be applied in functional foods.

Highlights

Antioxidant activities of 11 lactobacilli were examined. Lactobacillus plantarum C88 displayed strong antioxidant effects both in vitro and in vivo. ► L. plantarum C88 could be explored as a novel antioxidant.

Introduction

Reactive oxygen species (ROS) such as superoxide anion (radical dotO2), hydrogen peroxide (H2O2), and hydroxyl radical (radical dotOH) are produced during cellular metabolism. They play important roles in cell signalling, apoptosis, gene expression and ion transportation (Lü, Lin, Yao, & Chen, 2010). However, when these ROS molecules are generated in excess or cellular defences are deficient, biomolecules including protein, lipid, and nucleic acids can be damaged by the oxidative stress process. Such damage may lead to a variety of age-related degenerative diseases, such as cancer, Alzheimer’s disease, and Parkinson’s disease (Afonso, Champy, Mitrovic, Collin, & Lomri, 2007).

Most living organisms possess enzymatic and non-enzymatic antioxidant defence and repair systems that have evolved to protect them against oxidative stress. However, these native antioxidative systems are generally not enough to prevent the living organisms from oxidative damage. Antioxidant treatments using substances that delay or prevent the oxidation of cellular substrates have shown the potential to help the human body reduce oxidative damage. Although several synthetic antioxidants including butylated hydroxyanisole and butylated hydroxytoluene have been widely used in retarding lipid oxidation, their safety has recently been questioned, due to liver damage and carcinogenicity (Luo & Fang, 2008). Therefore, exploitation of safer, natural antioxidants from bio-resources that can replace synthetic antioxidants has received a great deal of attention in recent years.

Lactic acid bacteria (LAB) are Gram-positive bacteria, widely distributed in nature, and industrially important as they are used in a variety of industrial food fermentations. The potential benefits of LAB for human health include stimulation of the immune system, balancing intestinal flora, reducing serum cholesterol, and reducing the risk of tumours, etc. Lately, some LAB strains have been found with other important biological functions, such as anti-ageing and antioxidant activities (Ayeni et al., 2011, Kuda et al., 2010, Lee et al., 2010). Lactobacillus rhamnosus GG was found to inhibit lipid peroxidation in vitro due to iron chelation and superoxide anion scavenging ability (Ahotupa, Saxelin, & Korpela, 1996). Lactobacillus fermentum ME-3 isolated from a healthy Estonian child possessed Mn-superoxide dismutase activity and both its lysates and intact cells were capable of increasing the glutathione redox ratio in blood sera, and improving the composition of the low-density lipids (LDL) and post-prandial lipids (Mikelsaar & Zilmer, 2009). A fermented sea tangle solution with Lactobacillus brevis BJ20 exhibited strong DPPH scavenging, superoxide radical scavenging, and xanthine oxidase inhibition activities in vitro (Lee et al., 2010). Probiotic Lactobacillus casei Zhang was shown to alleviate oxidative stress by reducing lipid peroxidation and improving lipid metabolism both in blood and liver (Zhang, Du, Wang, & Zhang, 2010). Lactobacillus plantarum 7FM10 isolated from the traditional Japanese food narezushi exhibited DPPH and superoxide radical scavenging capacities (Kanno, Kuda, An, Takahashi, & Kimura, 2012).

Fermented products have been consumed for thousands of years in China. As the number who consume traditional Chinese fermented foods is increasing, there is an increasing interest in enhancing food safety, improving organoleptic attributes, enriching nutrients, and increasing health benefits (Liu, Han, & Zhou, 2011). These functional properties have partly been ascribed to the higher antioxidant properties of LAB involved in many fermentation processes of traditional Chinese foods (Huang et al., 2011, Wang et al., 2008). So far, little attention has been paid to the antioxidant activities of L. plantarum strains isolated from traditional Chinese products. Therefore, in the present study, the potential antioxidant activity of 11 L. plantarum strains isolated from traditional Chinese fermented foods was examined for their in vitro scavenging activity against hydroxyl and DPPH free radicals, and for their resistance to hydrogen peroxide. The in vivo antioxidant effect of a selected antioxidant L. plantarum strain chosen as a result of the in vitro tests was further studied in terms of certain antioxidant enzyme activities and lipid peroxidation levels, using model mice suffering oxidative stress induced by d-galactose to explore underlying molecular mechanisms.

Section snippets

Bacterial strains

Eleven Lactobacillus strains were used in this study, including 2 strains (C88 and C10) isolated from traditional fermented dairy tofu in Inner Mongolia of China (Zhang, Li, Zhao, Niu, & Yang, 2010), 8 strains (S7-2, S5-2, S6-1, S3-8, S4-5, S2-5, S5-6 and S4-2) from naturally fermented sauerkraut obtained from local families in the northeast region of China (Wang, Zhang, Li, Niu, & Yang, 2010), and a strain (K25) from Tibetan Kefir grains (Wang et al., 2012). Bacteria isolated from these

Scavenging of hydroxyl radical with intracellular cell-free-extracts

The results of scavenging for hydroxyl radical with the intracellular cell-free extracts of the 11 L. plantarum strains are shown in Fig. 1. All the strains demonstrated hydroxyl radical scavenging activity in a dose-dependent manner within the test concentration range of 108–1010 CFU/ml. Among the 11 strains tested, L. plantarum C88 had the highest hydroxyl radical scavenging ability with an inhibition rate of 44.31% at 1010 CFU/ml. L. plantarum strains C10, S3 -8, S4 -5, and K25 also

Discussion

Hydroxyl radical has been reported to be the most harmful ROS that is responsible for the oxidative injury of biomolecules, and it is mainly originated from Fenton reaction in the presence of transition metals such as iron (Fe2+) and copper (Cu2+). Chelation of these ions by certain antioxidants may inhibit the generation of hydroxyl radicals (Kao & Chen, 2006). Some LAB strains, such as Streptococcus thermophilus 821 (Lin & Yen, 1999), Bifidobacterium longum 15708 (Lin & Yen, 1999), and L.

Acknowledgements

The financial support for this work from Natural Science Foundation of China (31071574), China Agriculture Research Systems (CARS-37), and National Public Benefit Research (Agriculture) Foundation (200903043) is gratefully acknowledged.

References (30)

Cited by (343)

View all citing articles on Scopus
View full text