Determination of Antimicrobial Activity of Mexican Sunflower (Tithonia diversifolia) Leaf Extract against Selected Gram-Negative Bacteria

Introduction: The global rise of antibiotic resistance among pathogenic bacteria has become a significant public health concern, necessitating the exploration of novel antimicrobial agents. Tithonia diversifolia , commonly known as Mexican sunflower, has been traditionally used in various cultures for its medicinal properties, including the treatment of infectious diseases. The aim of this study was to investigate the antimicrobial activity of T. diversifolia leaf extract against common gram-negative bacteria such as Escherichia coli, Enterococcus faecalis, and Klebsiella pneumoniae. Methodology: Experimental research was conducted on fresh leaves of the Tithonia diversifolia extracts. The extracts were obtained by the maceration method, and the antibacterial activity was tested using the agar well diffusion method. Result: The ethanoic extract shows a good inhibition on E. coli and K. pneumoniae with the largest inhibition zone diameter was at a 100% concentration of 19 mm for E. coli and 15mm for K. pneumoniae , while the diameter of the smallest inhibition zone was at a 20% concentration of 6 mm for E. coli and 8mm for K. pneumoniae with no and less inhibition at 20% on both E. coli and K. pneumoniae respectively. The Aqueous extra shows no inhibition on both the selected Gram Negative bacteria on both the concentration in which all the concentration shows an inhibition zone of 6mm on all the selected pathogens Conclusions: T. diversifolia leaf extracts demonstrate varying antimicrobial efficacy, with ethanolic extracts showing greater antibacterial activity against selected Gram-negative bacteria ( E. coli and K. pneumoniae ) compared to aqueous extracts. Interestingly, E. faecalis exhibited growth around the aqueous extract discs, suggesting possible attraction rather than inhibition. While aqueous extracts showed no antimicrobial activity, the ethanolic extracts did demonstrate some inhibition, which was measurable through MIC testing.