SYNTHESIS AND CHARACTERIZATION OF NOVEL BENZALDEHYDE THIOSEMICARBAZONES AND EVALUATION OF THEIR ANTIBACTERIAL, ANTIFUNGAL AND ANTIOXIDANT ACTIVITY

In the present study 17 novel benzaldehyde thiosemicarbazone derivatives were synthesised using 2-methyl-3-thiosemicarbazide as the main reactant and different aromatic aldehydes. Reactions were monitored using thin layer chromatography technique and the newly synthesised derivatives were characterized by Elemental analysis, ATR and ¹HNMR techniques. For antibacterial activity four bacterial strains were selected namely Bacillus subtilis (gram +ve), Staphylococcus aureus (gram +ve), Escherichia coli (gram –ve), and Pseudomonas aeruginosa (gram -ve).Candida albicans was used to ascertain the antifungal activity of compounds. Antimicrobial assay was performed using nutrient agar media for the bacterial strains and Sabouraud agar for the fungus, zone of inhibition of all the compounds which could inhibit visible growth after incubation were calculated. Four different dilutions of the test compounds were taken and compared against ciprofloxacin and fluconazole as the standard drugs. Antimicrobial assay was performed in duplicate. The test compounds were active against both gram negative as well as gram positive bacteria. Considerable anti-fungal was shown by the compounds. Antioxidant assay was performed using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) or ABTS method and  2,2-diphenyl-1-picrylhydrazyl or DPPH method.