ABSTRACT

In the present work, selected plants were screened for their potential antibacterial activity. For evaluating antibacterial activity, both aqueous and organic solvent methanol was used. The plants screened were Ocimum sanctum, Jatropha gossypifolia, Boerhavia diffusa, Azadirachta indica, Solidago virgaurea, and Commelina benghalensis. The antibacterial activity was assessed against six bacterial strains--Pseudomonas testosteroni, Staphylococcus epidermidis, Klebsiella pneumoniae, Bacillus subtilis, Proteus morganii, Micrococcus flavus. Agar disc diffusion method and Agar ditch diffusion method were used to study the antibacterial activity of all these plants. Ps. testosteroni and K. pneumoniae were the most resistant bacterial strains. A. indica showed strong activity against tested bacterial strains. Therefore, we conclude that A. indica may prove to be a promising agent, and further exploration into this compound should be performed to determine its full therapeutic potential. In addition, its leaf extract can also be used as a lead molecule in combating the diseases caused by the studied bacterial strains.

In the present study, silver nanoparticles were synthesized using flower broth of Tagetes erecta as reductant by a simple and eco-friendly route. The aqueous silver ions when exposed to flower broth were reduced and resulted in green synthesis of silver nanoparticles. The silver nanoparticles were characterized by UV-visible spectroscopy, zeta potential, Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction, Transmission electron microscopy (TEM) analysis, Energy dispersive X-ray analysis (EDX) and selected area electron diffraction (SAED) pattern. UV-visible spectrum of synthesized silver nanoparticles showed maximum peak at 430 nm. TEM analysis revealed that the particles were spherical, hexagonal and irregular in shape and size ranging from 10 to 90 nm and Energy dispersive X-ray (EDX) spectrum confirmed the presence of silver metal.

The antibacterial activity of the crude methanol extract of Woodfordia fruticosa Kurz. flower was evaluated at two different concentrations by the agar well diffusion method. The methanol extract of the flower exhibited antibacterial activity at varied levels except against Bacillus subtilis and Micrococcus flavus. The methanol extract was most active against Pseudomonas pseudoalcaligenes. The extract was more active against Gramnegative bacteria as compared to Gram-positive. The inhibitory effect of the extract was compared with standard antibiotics, amoxicillin and ciprofloxacin.

The following Schiff bases have been synthesized: (1) 4-[(2-chlorobenzylidene)amino]benzoic acid [JP1], (2) 4-[(furan-2-ylmethylene)amino]benzoic acid [JP2], (3) 4-[(3-phenylallylidene)amino]benzoic acid [JP3], (4) 4-[(2-hydroxybenzylidene)amino]benzoic acid [JP4], (5) 4-[(4-hydroxy-3-methoxybenzylidene)amino]benzoic acid [JP5] and (6) 4-[(3-nitrobenzylidene)amino]benzoic acid [JP6].They were screened as potential antibacterial agents against a number of medically important bacterial strains. The antibacterial activity was studied against A. faecalis ATCC 8750, E. aerogenes ATCC 13048, E. coli ATCC 25922, K. pneumoniae NCIM 2719, S. aureus ATCC 25923, P. vulgaris NCIM 8313, P. aeruginosa ATCC 27853 and S. typhimurium ATCC 23564. The antibacterial activity was evaluated using the Agar Ditch method. The solvents used were 1,4-dioxane and dimethyl sulfoxide. Different effects of the compounds were found in the bacterial strains investigated and the solvents used, suggesting, once again, that the antibacterial activity is dependent on the molecular structure of the compound, the solvent used and the bacterial strain under consideration. In the present work, 1,4-dioxane proved to be a good solvent in inhibiting the above stated bacterial strains.