Green Route for Efficient Synthesis of Novel Amino Acid Schiff Bases as Potent Antibacterial and Antifungal Agents and Evaluation of Cytotoxic Effects

Abstract

Green chemical one-pot multicomponent condensation reaction of substituted 1H-indole-2,3-diones (1), various amino acids (2), and thiosemicarbazide (3) is found to be catalyzed by lemon juice as natural acid using water as a green solvent to give the corresponding Schiff bases (4) in good to excellent yields. This method is experimentally simple, clean, high yielding, and green, with reduced reaction times. The product is purified by simple filtration followed by washing with water and drying process. The synthesized compounds are characterized by FT-IR,13CNMR, and1HNMR spectroscopy and are screened for their antifungal activity againstAspergillus niger,Penicillium notatum,Fusarium oxysporum,Alternaria brassicicola,Chaetomium orium, andLycopodium sp.and antibacterial activity against Gram-positive bacteria,Bacillus licheniformis,Staphylococcus aureus, andMicrococcus luteus,and Gram-negative bacteria,Pseudomonas aeruginosaandEscherichia coli. Compounds have also been evaluated for cytotoxic effects against human colon cancer cell line Colo205.