Abstract

IN-VITRO ANTIBACTERIAL ACTIVITY OF CRUDE CITRUS EXTRACTS ON STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI ISOLATED FROM THE HUMAN SKIN AND STOOL RESPECTIVELY.

*Ezeadila Joachim O., Orubu Valerie A., Ejike Onyibo S. and Udemezue Onyekachukwu I.

Abstract

Medicinal plants play very important roles in herbal medicine. As antibiotics resistant bacteria are frequently encountered in the last two decades or more, medicinal plants are being exploited for products that could combat these superbugs. This study focuses on the in-vitro antibacterial activity of crude Citrus extracts on Staphylococcus aureus and Escherichia coli isolated from human skin and stool respectively. A total of 50 skin swab and rectal swab samples were randomly collected from some students of Nnamdi Azikiwe University, Awka and processed by culturing them on suitable media. The antibacterial activities of crude extracts of different Citrus fruits were determined using the disc diffusion method. The results obtained confirmed antibacterial activity of extracts of Citrus fruits with inhibition zone diameters comparing favourably to those of the commercial antibiotic discs. The highest zone of inhibition (19mm) was observed with the crude extract of Citrus limon and followed by Citrus aurantifolia (17mm) on Staphylococcus aureus, with a minimal effect on Escherichia coli producing zone of 11mm and 13mm respectively. The crude extract of Citrus paradisi produced a zone of inhibition of 11mm on Staphylococcus aureus, whereas Escherichia coli was resistant to it. The two organisms were both resistant to the crude extracts of Citrus sinensis. This study suggests that Citrus extracts especially those of Citrus limon and Citrus aurantifolia show great antibiotic potential against Staphylococcus aureus and Escherichia coli and thus promise an efficacious substitute of synthetic antibiotics, or evaluated for possible synergism when both are co-administered.

Keywords: Escherichia coli, Staphylococcus aureus, Citrus spp, antibacterial activity.