Evaluation of the Antibacterial Activity and Cytotoxicity of Extracts of Endophytic Bacteria Isolated from Solanum torvum Sw (Solanaceae)

Abstract

The study aimed at evaluating the antibacterial and cytotoxic potential of endophytic bacteria extracts isolated from Solanum torvum Sw (Solanaceae), a plant traditionally used in the treatment of many pathologies such as diarrheal diseases. Isolation of endophytic bacteria was done on supplemented and non-supplemented nutrient media. The extracts of these endophytes were obtained after fermentation in Muller Hinton Broth (MHB). An antibacterial screening of the extracts was carried out on 04 bacterial strains (Staphylococcus aureus, Shigella flexneri, Escherichia coli and Salmonella typhimurium). The strains having demonstrated activity were retained for the determination of the minimum inhibitory concentrations (MIC). The cytotoxicity tests of the extracts were carried out on healthy macrophage cells (Raw 264.7) and healthy kidney cells (Vero). A total of 41 isolates of endophytic bacteria were isolated from S. torvum. The antibacterial screening made it possible to retain 08 extracts which demonstrated antibacterial activity on the S. aureus and S. flexneri strains with MICs ranging from 100 to 200 μg/ml. All extracts exhibited weak cytotoxic activity except for one extract. Extracts of endophytic bacteria isolated from S. torvum showed antibacterial activity and low cytotoxicity on the pathogenic strains tested. This study shows that the endophytic bacteria of S. torvum are a source of antibacterial compounds to be explored to enrich the therapeutic arsenal against bacterial infections.