Evaluation of the antibacterial activity on strains responsible for diarrhoea; antioxidant and cytotoxic activities in vitro of the leaves and trunk bark of Vernonia conferta Benth (Asteraceae)

The high incidence of infectious diseases and the emergence of resistance to modern drugs are current public health concerns. This situation leads to the search for alternatives via medicinal plants. The objective of this study was to assess the properties of Vernonia conferta. We performed an experimental study. The plant material consisted of the leaves and trunk bark of V. conferta. The extraction was carried out by maceration using aqueous and hydro-ethanolic solvents, followed by phytochemical screening of the extracts. An evaluation of the antibacterial potential was carried out by the micro-dilution method and was followed by the evaluation of the antioxidant properties (DPPH and FRAP test) and cytotoxicity (resazurin staining) of the extracts. The E2 and E4 extracts exhibited better extraction yields. The phytochemical screening noted the presence of families of compounds in common (polyphenols, tannins and quinones) and those which are different. The hydro-ethanolic extracts exhibited antibacterial activity on the strains of interest with MICs varying from 2 to 32 mg / mL with a possibility of synergistic action between the compounds. The evaluation of the antioxidant properties showed that the extracts E1, E3 and E4 showed better properties with IC₅₀ = 25.1 ± 0.410; 2.456 ± 0.002; 2.363 ± 0.015 µg / mL respectively according to the tested method. The extracts showed their non-cytotoxicity with CC₅₀> 1000 µg / mL. The activities of hydro-ethanolic extracts of V. conferta suggest that the latter would be a potential raw material for the production of improved traditional medicines.