Antimicrobial activity of the essential oils of three species of Pogostemon.

Antimicrobial studies on 7 strains of bacteria and 8 strains of fungi using disk diffusion assay, revealed potential activities of crude essential oils in Pogostemon benghalensis, P. purpurascens and P. vestitus. Essential oils produced highest inhibition zones against Staphylococcus aureus (39.33, 37.33 and 35.67 mm for P. benghalensis essential oil) and Candida albicans (34.33, 26.33 and 17.67 mm for P. purpurascens essential oil) among bacteria and fungi respectively, when compared with pure reference standards (35 mm for Gentamycin sulphate (40 mg ml(-1)) against S. aureus and 30.33 mm for Nystatin [50 IU] against C. albicans). Results also indicated the existence of potential antimicrobial activity of Pogostemon essential oils against other microorganisms viz., Proteus vulgaris, E. coli and Aspergillus parasiticus. Leaf essential oils of P. purpurascens and P. benghalensis can be considered as a new source for developing local antifungal and antibacterial agents. An attempt was made to highlight the promising plant species for further investigation which leads to drug development.

Antimicrobial activities of Eusteralis deccanensis and E. quadrifolia essential oils.

Antimicrobial activity of the essential oils of Eusteralis deccanensis and E. quadrifolia were investigated on Bacillus subtilis, B. megaterium, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Rhizopus oryzae, Aspergillus niger and Colletotrichum musae. Both the oils possess growth inhibitory activity against most of the microorganisms tested.