DOI: https://doi.org/10.36347/sajb.2026.v14i10.002

Pages: 658-665

Infectious diseases pose a significant challenge in Côte d’Ivoire. While treatments for these conditions exist, repeated therapeutic failures due to pathogen resistance have called into question the curative efficacy of current anti-infective agents. This study aims to provide a scientific basis for the traditional therapeutic use of the medicinal plant Mallotus oppositifolius (Geisel.) Müll.-Arg (Euphorbiaceae). It involved investigating the antibacterial activity of hexane, chloroform, ethyl acetate, and butanol fractions derived from an 80% methanolic extract of Mallotus oppositifolius leaves against seven strains of Pseudomonas aeruginosa (comprising six clinical isolates with resistant phenotypes and one reference strain). An agar well diffusion method was used to assess strain susceptibility. A screening test identified the two most active fractions for the determination of antibacterial parameters via the broth macro-dilution method. Biological analyses demonstrated the superior activity of the ethyl acetate fraction; at a concentration of 50 mg/mL, it produced the largest zone of inhibition (18.5 ± 0.6 mm) against P. aeruginosa strain 1780C/14. With the exception of the chloroform fraction, the other fractions generally exhibited remarkable activity, characterized by zones of inhibition exceeding 10 mm. Minimum Inhibitory Concentrations (MICs) ranged from 0.19 to 0.78 mg/mL for the ethyl acetate fraction and from 0.39 to 0.78 mg/mL for the butanol fraction. The latter demonstrated bactericidal activity against all tested bacterial strains. Furthermore, TLC analysis of the fractions revealed a profile rich in secondary metabolites, including sesquiterpene lactones, saponins, flavonoids, anthrones, anthraquinones, alkaloids, tannins, and coumarins. The combined presence of these bioactive compounds supports the therapeutic potential of Mallotus oppositifolius. These results validate the therapeutic use of this plant in African pharmacopoeia.