Evaluation of Antibacterial Activity and Cytotoxicity of Leaf Extracts from the Plant Diospyros mespiliformis

Abstract

This study explores the plant Diospyros mespiliformis for its antibacterial and cytotoxic properties. This plant seems to have a well-documented history in traditional medicine. Diospyros mespiliformis is a plant used in traditional medicine for the treatment of many illnesses, particularly wounds. In this context, ethanolic (E.F), hydroethanolic (H.F) and aqueous (A.F) extracts of the plant's leaves were evaluated for their antimicrobial properties. The study was carried out on four species of bacteria, two Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and two Gram-negative (Pseudomonas aeruginosa and Escherichia coli). The results show that, with the exception of Escherichia coli, the other strains showed sensitivity to the extracts. In addition, with the exception of Enterococcus faecalis, the crude ethanolic and aqueous extracts were more active than the hydro-ethanolic extracts against the microbial strains. Inhibition diameters for the Pseudomonas aeruginosa strain were 08 mm, 00 mm and 08 mm for the ethanolic, hydro-ethanolic and aqueous extracts, respectively. For the Enterococcus faecalis strain, they were 08 mm, 10 mm and 09 mm, respectively for the three extracts.  For the Staphylococcus aureus strain, the characteristic inhibition diameters were 11 mm, 09 mm and 10 mm, respectively for the different extracts. The minimum inhibitory concentration (MIC) for Pseudomonas Aeruginosa was 9375 µg/mL for both ethanolic and aqueous extracts. For the Staphylococcus Aureus strain, it was 586 µg/mL for both ethanolic and aqueous extracts. For the Enterococcus Faecalis strain, it was 1171 µg/mL for all three extracts. The safety of the compounds present in these extracts was studied through toxicity tests on different categories of hepatocytic liver cells, notably Huh7, Hep3B and HepaRG. Comparative analysis of the IC50 of the extracts and controls, including the anti-cancer drug sorafenib and aflatoxin, revealed very low toxicity of the extracts towards the cells tested compared with the controls. The crude extract, which is usually distributed in the form of a mixture, may contain compounds that can affect the state of certain cells in the body. Thus, purification or isolation of the compounds responsible for the biological activities noted could make the use of plant extracts by humans for medicinal purposes even safer.