Phytochemical and antibacterial properties of garlic extracts

The antibacterial potency of aqueous and methanol extracts of garlic was determined invitro against three bacterial isolates (Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa) by agar well diffusion method. Preliminary phytochemical screening revealed the presence of tannin, flavonoid, carbohydrate, protein, saponin, alkaloid and glycoside in the plants while anthraquinone was absent. Both the aqueous and methanol extract of garlic were observed to be more potent against E. coli with maximum zone of growth inhibition of 21.5mm at 200mg/ml and 24.0mm at 200mg/ml respectively. The minimum inhibitory concentration (MIC) of the aqueous and methanol extracts of garlic against E. coli was 100mg/ml and 50mg/ml respectively, and for S. aureus it was 200mg/ml and 100mg/ml respectively. Similarly, The MIC against Pseudomonas aeruginosa for the aqueous and methanol extracts was 200mg/ml and 200mg/ml respectively. Higher minimum bactericidal concentration (MBC) of 300mg/ml was observed against P. aeruginosa with aqueous extract and 250mg/ml with the methanol extract. The MBC for both the aqueous and methanol extract was 200mg/ml respectively against E. coli while MBC of 300mg/ml was observed against S. aureus for the aqueous extract and 200mg/ml for the methanol extract. These findings therefore justify the traditional medicinal use of garlic.Keywords; Phytochemical, Antibacterial, Efficacy, Garlic, Isolates.