Preliminary Investigation of the Antibacterial Activity of Psidium guajava Extracts

Psidium guajava (guava tree plant) is widely used in Nigerian communities as food and for medicinal purposes to treat some bacterial and non-bacterial related diseases. Increase in the rate at which pathogenic bacteria develop resistance to some available synthetic drugs calls for urgent action to turn the search lights on natural products such as plants for bioactive compounds needed to develop novel antimicrobials. This study evaluated the antibacterial activity of ethanolic and methanolic crude leaf and bark extracts of P. guajava against pathogenic strains of Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Streptococcus pneumoniae by the agar well diffusion technique. Ethanolic and methanolic leaf extracts of P. guajava produced inhibitory zones of 15-22 mm and 13-20 mm against the test bacteria respectively. Inhibitory zones of 16-19 mm and 13-23 mm was recorded against the test bacteria for methanolic and ethanolic bark extracts respectively. The observed antibacterial activities of P. guajava further explain the use of guava tree plant for medicinal purposes in this part of the world. And further research is necessary to characterize the bioactive compounds of P. guajava.