Reduction of Aflatoxin B1 Toxicity by Lactobacillus plantarum C88: A Potential Probiotic Strain Isolated from Chinese Traditional Fermented Food "Tofu"

In this study, we investigated the potential of Lactobacillus plantarum isolated from Chinese traditional fermented foods to reduce the toxicity of aflatoxin B-1 (AFB(1)), and its subsequent detoxification mechanism. Among all the investigated L. plantarum strains, L. plantarum C88 showed the strongest AFB(1) binding capacity in vitro, and was orally administered to mice with liver oxidative damage induced by AFB(1). In the therapy groups, the mice that received L. plantarum C88, especially heat-killed L. plantarum C88, after a single dose of AFB(1) exposure, showed an increase in unabsorbed AFB(1) in the feces. Moreover, the effects of L. plantarum C88 on the enzymes and non-enzymes antioxidant abilities in serum and liver, histological alterations of liver were assayed. The results indicated that compared to the control group, L. plantarum C88 alone administration induced significant increase of antioxidant capacity, but did not induce any significant changes in the histological picture. Compared to the mice that received AFB(1) only, L. plantarum C88 treatment could weaken oxidative stress by enhancing the activity of antioxidant enzymes and elevating the expression of Glutathione S-transferase (GST) A3 through Nuclear factor erythroid (derived factor 2) related factor 2 (Nrf2) pathway. Furthermore, cytochrome P450 (CYP 450) 1A2 and CYP 3A4 expression was inhibited by L. plantarum C88, and urinary aflatoxin B-1-N-7-guanine (AFB-N-7-guanine), a AFB(1) metabolite formed by CYP 1A2 and CYP 3A4, was significantly reduced by the presence of viable L. plantarum C88. Meanwhile, the significant improvements were showed in histological pictures of the liver tissues in mice orally administered with viable L. plantarum C88. Collectively, L. plantarum C88 may alleviate AFB(1) toxicity by increasing fecal AFB(1) excretion, reversing deficits in antioxidant defense systems and regulating the metabolism of AFB(1).