The hexane, ethyl acetate, dichloromethane, methanol extracts and spent media (extracellular substances) were tested in vitro for their antibacterial activity for which one Gram-positive bacterium (Staphylococcus aureus) and four Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumoniae) were used as test organisms. The methanol extract showed more potent activity than other organic extracts, spent medium of the culture exhibited little activity against E. coli only. No inhibitory effect was found against Klebsiella pneumoniae .The broth microdilution assay gave minimum inhibitory concentrations (MIC) values ranging from 1 to 512 μg/ml. The MIC of methanol extract against S. aureus and E. coli were 128 μg/ml and 256 μg/ml, respectively.

Various parts of Datura innoxia were examined for potential antibacterial activity by preparing their crude aqueous and organic extracts against Gram-negative bacteria (Escherichia coli and Salmonella typhi) and Gram-positive bacteria (Bacillus cereus, Bacillus subtilis and Staphylococcus aureus). The results of agar well diffusion assay indicated that the pattern of inhibition depends largely upon the plant part, solvent used for extraction and the organism tested. Extracts prepared from leaves were shown to have better effi cacy than stem and root extracts. Organic extracts provided potent antibacterial activity as compared to aqueous extracts. Among all the extracts, methanolic extract was found most active against almost all the bacterial species tested. Gram-positive bacteria were found most sensitive as compared to Gram-negative bacteria. Staphylococcus aureus was signifi cantly inhibited by almost all the extracts even at very low MIC followed by other Gram-positives. For Escherichia coli (a Gram-negative bacterium), the end point was not reached for ethyl acetate extract while it was very high for other extracts. The study promises an interesting future for designing a potentially active antibacterial agent from Datura innoxia.

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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.