Evaluation of Various Crude Extracts of Zingiber officinale Rhizome for Potential Antibacterial Activity: A Study in Vitro

In vitro antibacterial activity of crude aqueous and organic extracts of rhizome of Zingiber officinale Roscoe (ginger) was studied against both Gram-negative (Escherichia coli and Salmonella typhi) and Gram-positive (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus and Streptococcus pyogenes) bacterial strains. The present study reveals that the pattern of inhibition varied with the solvent used for extraction and the organism tested. Plant extracts prepared in organic solvents provided more consistent antibacterial activity as compared to aqueous extracts. Methanol extract was the most active against maximum number of bacterial species tested. Gram-positive bacteria were found the most sensitive as compared to Gram-negative bacteria. Staphylococcus aureus was significantly inhibited by almost all the extracts even in very low MIC followed by other Gram-positives. Escherichia coli (a Gram-negative bacterium) was showing the least inhibition with highest MIC values, while Salmonella typhi was found completely resistant. Methanol extract yielded the presence of terpenoids, flavonoids, alkaloids and tannins in phytochemical screening. Results of the present study sign the interesting assurance of designing a potentially active antibacterial agent from Zingiber officinale.