ABSTRACT

Plants are indeed the first material used in alternative medicine type of remedy against many diseases. The aim of this study was to evaluate the antibacterial effect of unripe citrus lemon extracts. Samples of fresh unripe lemon fruits were procured from horticulture unit in National Root crops Research in Umuahia, Abia State, Nigeria. Bacterial cultures used in this study include Staphylococcus aureus, Pseudon2onas spp and Eschecheria coli and they were obtained from Mercy specialist Laboratory, in Umuahia. The confirmation of these isolates was carried out by routine bacteriological methods, which include the cultural examination, microscopic examination, colony morphology, preliminary test like Gram staining and some biochemical tests such as Catalase test, Coagulase test, Citrate test, Motility test, Indole test, Triple Sugar Iron test and Sugar fermentation test. Qualitative photochemical constituent analysis of the unripe citrus lemon samples showed the presence of Tannis, flavonoids, phenols, alkaloids, steroids and terpenoid. There was no presence of saponins. Tannins had the highest concentration seconded by flavonoid, followed by phenol, alkaloid and terpenoid. The highest inhibitory activity of the unripe lemon ethanol extract was recorded on Staphylococcus aureus (18mm) at l0Omg/ml concentration while Pseudomonas aeruginosa (10mm) was the least inhibited (10mm) at 25mg/mi concentration. E.coli recorded the highest inhibited by the unripe lemon water extract( 19mm) at 100mg/ml concentration while Pseudomonas aeruginosa recorded the least inhibited (9mm) at 25mg/ml concentration. The MIC of unripe lemon ethanol extracts required to inhibit the growth of Staphylococcus aureus was 50mg/ml and MBC of 100mg/ml, while the MIC required to inhibit the growth of Pseudomonas aeruginosa was 50mg/mi and MBC of 100mg/ml. The MIC of unripe lemon water extracts required to inhibit the growth of Staphylococcus aureus was 50mg/mi and MBC of 100mg/ml, while the MIC required to inhibit the growth of Pseudomonas aeruginosa was 100mg/mi and MBC of 100mg/mi. The result obtained from the current study has proven the antibacterial activity of unripe citrus lemon extract on some selected isolates (S. aureus, E. coli and P. aeruginosa). It is therefore recommended that further studies can be carried out in order to fractionize and incorporate citrus lemon fruit extracts into synthetic drugs and ointments and also test them on some other isolates.