ABSTRACT
The present study reports the synthesis of 2-azidobenzothiazoles from substituted 2-aminobenzothiazoles using sodium nitrite and sodium azide under mild conditions. All the synthesized compounds were examined for their antibacterial activity against Gram (+) bacteria, Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 51299), Bacillus cereus (ATCC 10876) and Gram (-) bacteria, Escherichia coli (ATCC 10536), Pseudomonas aeruginosa (ATCC 10145), Klebsiella pneumonia (ATCC BAA-2146)and clinical isolates of Gram (+) Methicillin Resistant S. aureus (MRSA) and Multi Drug Resistant E. coli. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values by broth dilution method revealed that compound 2d exhibited significant antibacterial potential against E. faecalis and S. aureus with MIC of 8 µg/mL, while other synthesized compounds had only moderate effects against all the tested species. The compound significantly inhibited the biofilm formation of the bacterial strains below its MIC. The selective cytotoxicity of Compound 2d towards bacterial cells was evidenced on extended exposure of Human Embryonic Kidney-293 cell line to higher concentrations of the compound. Hence, the present study confirmed that compound 2d can be a potential drug candidate for future development as an antibacterial drug.
ABSTRACT
The essential oil from the leaves of Juglans regia L. (Juglandaceae) growing wild in Kashmir (India) was obtained by hydrodistillation and analysed by a combination of capillary GC-FID and GC-MS. A total of 38 compounds, representing 92.7% of the oil, were identified and the major components were found to be α-pinene (15.1%), ß-pinene (30.5%), ß-caryophyllene (15.5%) germacrene D (14.4%) and limonene (3.6%). The essential oil and the main individual constituents were screened for antibacterial activity and the essential oil evaluated for antioxidant activity. Antibacterial activity was evaluated using the disc diffusion and microdilution methods against a group of clinically significant Gram-positive (Staphylococcus epidermidis MTCC-435, Bacillus subtilis MTCC-441, Staphylococcus aureus) and Gram-negative bacteria (Proteus vulgaris MTCC-321, Pseudomonas aeruginosa MTCC-1688, Salmonella typhi, Shigella dyssenteriae, Klebsiella pneumonia and Escherichia coli). The essential oil and its major components exhibited broad spectrum inhibition against all the bacterial strains with Gram-positive being more susceptible to the oil than Gram-negative bacteria. Antioxidant activity of the oil was evaluated by the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) and hydroxyl radicals. In general, the essential oil exhibited high antioxidant activity which was comparable to the reference standards at the same dose (ascorbic acid and butylated hydroxyl toluene, BHT) with IC(50) values of 34.5 and 56.4µg/ml calculated by DPPH and hydroxyl radical scavenging assays respectively.
