Research – Antibacterial activity of sweet orange (Citrus sinensis) juice extract on selected bacteria


Plants have potentials to be developed into many new drugs yet to be discovered because of the countless chemical compositions in them. The investigation is targeted at the antibacterial activity of sweet orange juice extract on some bacteria using ethanol and ethyl ethanoate solvent to extract juice. Ditch method was used for the sensitivity testing against Escherichia coliStaphylococcus aureusKlebsiella pneumoniae and Neisseria gonorrheae with a dilution factor of 10-10 for inoculation from pure culture of each selected bacteria. Disc method was used to test streptomycin, ciprofloxacin, gentamycin and penicillin G against test organisms as positive controls. There was no significant difference in the effect of different concentrations of the same extract on test organisms. However, there was a significant difference in the ethyl ethanoate and alcohol extracts. The ethyl ethanoate extract showed minimum inhibitory concentration at 300 mg/ml on E. coli (31.5 ± 0.5 mm); Ngonorrheae (21 ± 0.0 mm) at 200 mg/ml; Saureus (22 ± 0.0 mm) and Kpneumoniae (37 ± 3.0 mm) at 100 mg/ml; while ethanol extract at 100 mg/ml on E. coli (23.5 ± 1.5 mm) and Kpneumoniae (25 ± 5.0 mm);  N. gonorrheae (13.5 ± 1.0 mm) and S. aureus (12.5 ± 2.5 mm) at 300 mg/ml and 200 mg/ml respectively. The zones of inhibition exhibited by streptomycin ranges from Ngonorrheae (14-24 mm) E. coli; ciprofloxacin varies from 15- 21 mm on K. pneumoniae and S. aureus respectively. Gentamycin ranges from 14-20 mm on N. gonorrheae and S. aureus respectively; and penicillin G on N. gonorrheae (14 mm) and Saureus (28 mm). It can be concluded that sweet orange juice of ethyl ethanoate extract was more effective than the ethanol extract and the positive control.

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