Affiliation: Centre for Biotechnology, Maharshi Dayanand University, Rohtak -124001, Haryana, India.
The biological properties of medicinal plants have been documented worldwide for many centuries. However, the top priority for the biomedical field is the search for safe and effective antibacterial agents against the wide variety of bacterial infections. Therefore, the present study aimed to evaluate various phytoconstituents and in-vitro antibacterial activity of crude extracts from Aegle marmelos, Capparis aphylla, Callistemon lanceolatus, Commelina bengalensis, Justicia adhatoda, Argemona mexicana, Achyranthes aspera, Catharanthus roseus and Syzygium cumini. The antibacterial activity of different solvent (Petroleum ether, Chloroform, Acetone, Methanol and water) extracts prepared from nine plants were screened against some reference strain of bacteria (Escherichia coli, Vibrio cholerae, Klebsiella pneumoniae, Proteus vulgaris, Bacillus subtilis, Salmonella typhi) by using resazurin based microtitre dilution assay and disc diffusion assay. The presence of phenols, tannins, flavanoids, terpenoid, steroids, alkaloids and saponins in the different extracts were established. A minimum inhibitory concentration of these bioactive extracts ranges from 6.00 to 0.37 mg/ml. In disc diffusion assay, at concentration of 25.0 µg/disc of some crude extracts showed significant activity against six bacterial strains. Gas chromatography-mass spectrometry (GCMS) studies were performed for the most bioactive plant leaves’ extracts which resulted in the identification of several bioactive compounds. Moreover, the most of bioactive extracts were found to be safe and non-toxic by acute toxicity study. This data indicate that these naturally occurring medicinal plants have antibacterial potential and could be active as new potential antibacterial drugs with least toxic effects.