Antibacterial Properties and GC/MS Analysis of Alliium Sativum (Garlic)

This research was carried out to determine the antibacterial potency of fresh garlic extract against two bacterial isolates Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by agar well diffusion method. This was to validate its traditional use in treating infectious bacterial diseases. A phytochemical screening on the extract was also carried out to determine the various chemical components in garlic. To achieve the extract, fresh garlic was subjected to solvent extraction using n-hexane. The solvent was removed by using rotary evaporator at 37 oC and a light –yellow, oily liquid was attained. Thin Layer Chromatography (TLC) was then performed using redistilled methanol and hexane in the ration of 1:3 (v/v). TLC showed that there was isolation of three compounds from the extract whose Retardation Factors (RF) were calculated. The extract was then used for further analysis to ascertain the extent of bacterial inhibition on two strains of bacteria. The results showed that the extract was more potent on E. coli with maximum zone inhibition of 35 mm at 200 mg/ml whereas that of S. aureus was 28 mm at 200 mg/ml. Gas chromatography- mass spectroscopy (GC-MS) analysis of the extract confirmed the presence of Sulphur (-S) containing groups which are associated with bacterial inhibition in conventional antibiotics. The three major constituents obtained from the sample suspected to contain antibacterial activity include; (a) 3-Vinyl-1, 2-dithiacyclohex-5-ene (55.2%) (b), Trisulphide, di-2-propenyl (59.9%) and (c) 3-Vinyl-1, 2-dithiacyclohex-5-ene (71.3%). Further analysis on the garlic extracts need to be undertaken so as to provide antimicrobial agents and models for new generation of synthetic antibiotics. 

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