Phytochemical analysis and antibacterial activity of Psidium guajava L. leaf extracts

Abstract

The increasing menace of antimicrobial resistance in many pathogenic microbes has led to the search for long lasting remedy. The aim of this study was to examine the phytochemical and antimicrobial properties of extracts of Psidium guajava leaves against some clinical bacterial isolates. The plant leaves were extracted in three solvents namely; water, ethanol and methanol. The pathogenic bacterial isolates were Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae and Klebsiella pneumoniae all isolated from urine samples. The phytochemical analysis showed the presence tannins, flavonoids, alkaloids, saponins, glycosides and terpenoids in different proportions. The mean antibacterial activity of the extracts in vitro showed that the ethanolic extract was most efficacious at 25 mg concentration, inhibiting P. aeruginosa (9.50 mm), E. coli (9.00 mm), S. pneumoniae (10.50 mm) and K. pneumoniae (9.50 mm). The aqueous extract at 100 mg concentration inhibited E. coli (12.50 mm), S. aureus (14.50 mm) and S. pneumoniae (9.00 mm). This study has revealed that the leaves extract of P. guajava contains antibacterial and phytochemical substances which can be harnessed in satiation of human quest for better and healthier living.