RESUMO
Due to ever increasing antibiotic resistance offered by pathogenic bacterial strains and side effects of synthetic antibiotics, thereof, there is a need to explore the effective phytochemicals from natural resources. In order to help overcoming the problem of effective natural drug and the side effects posed by the use of the synthetic drugs, five different plants namely Thymus vulgaris, Lavandula angustifolia, Rosmarinus officinalis, Cymbopogon citratus and Achillea millefolium were selected to study their antibacterial potential. Antibacterial activity and minimum inhibitory concentration [MIC] checked against the selected bacterial strains. As compared to other test plants, ethanolic extract of Rosmarinus officinalis leaves showed the most promising inhibitory effect i.e: inhibition zone [18.17+/- 0.44mm] against Klebsiella pneumoniae and the lowest inhibition [15.5+/-0.29mm] against Pseudomonas aeruginosa and Escherichia coli [p<0.05]. The MIC values were recorded in the range of 1 to 20mg/ml. Screening of the selected extracts for the test plants additionally indicate some unique variations. Results were further confirmed through TLC for alkaloids and terpenoids [15% sulphuric acid and Dragedroff's reagent] in ethanolic extract. Characterization of Rosmarinus officinalis of ethanolic extract was carried out using column chromatography. The appearance of orange crystals may indicate the presence of alkaloidal bioactive compounds which need to be further investigated. The tested plants may have a potential for fighting against some infectious diseases caused by selected human pathogenic bacterial strains. This knowledge may incite a gateway to effective drug search and so on