In vitro antibacterial activity and phytochemical studies of methanolic extract of leaves of Hypericum perforatum L. growing wild in Kashmir Himalaya

To evaluate in vitro antibacterial activity and phytochemical analysis of methanolic extract of aerial parts of Hypericum perforatum L. growing wild in Kashmir Himalaya. Antibacterial activity was determined by agar well diffusion method and broth dilution assay against six bacterial strains comprising both standard laboratory and clinical strains. Phytochemical study was performed by using standard phytochemical methods. The extract showed pronounced activity against all the bacterial strains tested. Bacillus subtilus MTCC- 441 exhibited the maximum antibacterial activity against with mean zone of inhibition of 19.33 mm at concentration of 50 mg/ml. Minimum inhibitory concentration (MIC) ranged from 0.39 mg/ml for Bacillus subtilus MTCC- 441 to 3.12 mg/ml for Salmonella typhi and E. coli. The extract showed higher sensitivity against Gram positive bacterial strains than Gram negative bacterial strains. Quantitative estimation of bioactive phytoconstituents showed that the plant contains alkaloids (19.10 ± 0.4 mg/g plant sample), phenolics (21.90 ± 0.9 mg/g sample), flavanoids (17.10 ± 0.02 mg/g sample), tannins (1.60 ± 0.08 mg/g sample) and carbohydrates (4.0 mg/g sample). Our study clearly indicates that the methanolic extract of Hypericum perforatum from high altitude of Kashmir Himalaya possess significant antibacterial activity against diverse bacterial strains due to higher concentration of bioactive phytoconstituents like alkaloids, phenolics, flavanoids and tanins