Microbial regulation and protective effects of yerba mate (Ilex paraguariensis) in gamma-irradiated mice intestine

The small intestinal epithelium is highly sensitive to radiation and a major site of injury during radiation therapy and environmental overexposure. The objective of this study was to evaluate yerba mate extract (MT) as a potential radioprotective agent in the intestine. First yerba mate was exposed to doses of gamma radiation and the extract was analyzed for its antimicrobial, antioxidant and total phenolic compounds. Male mice were divided into 4 groups: Control group: received saline, MT group: received MT, Irradiation group: exposed to 8 Gy of gamma radiation, MT+ irradiation group: pre-treated with MT then exposed to gamma radiation. The results obtained in vitro showed that, MT of gamma irradiated yerba mate showed a reduction in antioxidant activity and total phenolic compounds compared to control. MT exerted antimicrobial activity with minimum inhibitory concentration (0.5 mg/ml) for Lactobacillus, Escherichia coli, Staphylococcus aureus and Streptococcus faecalis. In vivo, mice exposed to gamma radiation, showed significant reduction in the total microbial count and disappearance of E. coli, induction of lipid peroxidation, protein carbonyl, advanced oxidation protein products, and a decrease in glutathione, also decrease in the activity of lysozyme, catalase and superoxide dismutase, induction in cytokine levels of TNF-α and IL-6 with DNA fragmentation in the intestine, while irradiated mice pre-treated with MT showed, normalized lactic acid bacteria count and diminished pathogenic bacteria as S. aureus and E. coli also showed ameliorative effect of MT on lipid peroxidation, glutathione, protein carbonyl, advanced oxidation protein products, also normalized the activity of lysozyme, catalase and superoxide dismutase, and ameliorated cytokine levels of TNF-α and IL-6 compared to control, with radioprotection effect on the DNA of intestinal tissue. Our data suggested that, pre-treatment with MT may protect the small intestine from gamma radiation damaging effects showed in the measured biochemical parameters also maintained the microbial flora of lactic acid bacteria and removed pathogenic bacteria and may replace antibiotics description for radiotherapy patients since it showed antimicrobial effect against pathogenic bacteria.