Antibacteria Activities of Guava (Psidium guajava) and Orange (Citrus sinensis) Leaves Extracts on Staphylococcus aureus and Escherichia coli

Abstract

his study aimed at determining the antibacterial activities of Psidium guajava and Citrus sinensis leaves extracts of aqueous, ethanol, and methanol on Staphylococcus aureus and Escherichia coli. Dimethyl sulfoxide was used for dissolving the leaves extracts and the minimum inhibitory concentration (MIC) of the extracts was determined using broth dilution technique to observe their antibacterial activities against S. aureus and E. coli. The phytochemical screening revealed the presence of metabolites (flavonoids, tannins, steroid saponins, saponins and alkaloids). The inhibition zone of the aqueous, ethanol and methanol extracts of P. guajava and C. sinensis against Staphylococcus aureus and Escherichia coli was highest at 200mg/ml (18mm and 17mm), while the least inhibition zone was at 12.5mg/ml (7mm and 0mm) respectively. The aqueous extracts of P. guajava and C. sinensis against E. coli and S. aureus had its MIC at 50g/ml and 100mg/ml respectively, while ethanol extracts of P. guajava and C. sinensis  against the bacterial (E. coli and S. aureus) had its MIC at 50g/ml. The methanol extracts of P. guajava and C. sinensis showed the growth of S. aureus in all concentrations (12.5g/ml, 25g/ml, 50g/ml, 100mg/ml and 200mg/ml) while E. coli  had no growth from 100mg/ml above concentrations and 50g/ml (MIC) of P. guajava leaf extracts. These findings, therefore support the traditional use of Psidium guajava and Citrus sinensis for its curative potential to synthetic drugs which are expensive, not easily accessible with potential side effects.