Phytochemical screening and antibacterial potentials of the garlic (Allium sativum) extracts against clinical isolates

Abstract

This study investigated various phytochemicals and antibacterial activity of garlic (Allium sativum) bulb extract on five clinical bacterial pathogens using the agar well diffusion method. These bacteria include; Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella sp, Escherichia coli, and Salmonella typhi. Two different extracts were obtained from the bulbs of garlic (ethanol-soluble and methanol-soluble extracts). Phytochemical screening of the garlic bulb extracts indicated the presence of glycosides, steroids, phlobatanins, flavonoid, alkaloids, terpenoids and carbohydrate while saponin, phenolics and tannins were absent. There were zones of inhibitions around the wells which indicate that the organisms were sensitive to both ethanol and methanol extract of garlic having inhibitory strength on the test organisms ranging from 2-32 mm. The MIC and MBC revealed the isolates behaved differently in their sensitivity ranging from ranged from 20 - 76 mg/mL for ethanolic extract, while methanolic extract has ranged from 13 - 62 mg/mL. The methanol extract of the garlic bulb was absolutely more effective against five pathogenic bacteria than the ethanolic extract. This study indicates that Allium sativum had great antibacterial effect thus confirming its usage in herbal medicine.