Investigation of the antibacterial activities of methanolic and water extracts of Gongronema latifolium, Psidium guajava and Aspilia africana

Abstract

The epidemiological consequences of co-infections by enteric, wound, opportunistic, and drug-resistant pathogens, underscore the need for alternative and multi-target therapeutic approaches. Phytochemical properties of some plants are widely known but their potential utility as cheaper multi-target therapeutic options, have rarely been investigated. In the current work, Gongronema latifolium, Psidium guajava, and Aspilia africana extracts were studied for their potential utility as multi-target therapeutic alternatives. The plants were screened for phytochemical constituents. Based on the CLSI disc diffusion assay, the sensitivities of Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, and Pseudomonas aeruginosa to the plants’ extracts were tested. The minimum inhibitory concentration of the extracts against susceptible bacteria was determined by CLSI broth microdilution protocols. The major families of plant bioactive compounds were detected, with alkaloids, terpenoids, and flavonoids common to the three plants investigated. The plant extracts showed variable activity against the test bacteria (activity index, AI range = 0.43 – 2.59), while the highest activity based on the MIC was recorded for P. guajava (MIC range = 25- 100mg/ml). These results provide the basis of the plants’ therapeutic uses in folk medicine. Their activity index suggests the need for further investigation of their phytochemical components for potential medicinal application. The P. guajava methanolic extract with consistent activity across the test bacteria suggests its potentials in the formulation of multi-target antibiotic therapies