Synthesis and evaluation of in vivo antioxidant, in vitro antibacterial, MRSA and antifungal activity of novel substituted isatin N-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)thiosemicarbazones

Abstract

Some new isatin N-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)thiosemicarbazones 4a-t with different substituents at 1-, 5- and 7-positions of isatin ring have been synthesized by reaction of N-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)thiosemicarbazide 2 with corresponding isatins 3a-t. Compounds 4a-t were evaluated in vivo for antioxidant activity and in vitro for anti-microorganism activities. The MIC values were found for Gram positive bacteria (MIC = 1.56-6.25 μM), for Gram negative bacteria (MIC = 12.5 μM), and for fungi Aspergillus niger (MIC = 3.12-12.5 μM), Fusarium oxysporum (MIC = 6.25-12.5 μM) and Saccharomyces cerevisiae (MIC = 6.25-12.5 μM). Regarding the antioxidant activity, the SOD, GHS-Px and catalase activities of 4c-i and 4m-r were MIC = 10.57-10.85, 0.27-0.93 and 345.45-399.75 unit/mg protein, respectively. Compounds 4e-h had MIC values of 0.78, 1.56, and 3.12 μM for three clinical MRSA isolates. Compound 4e showed the selective cytotoxic effects against some cancer (LU-1, HepG2, MCF7, P338, SW480, KB) cell lines and normal fibroblast cell line NIH/3T3.

Keywords: Antibacterial; Antifungal; Antioxidant activity; Cytotoxic effects; D-glucose; Isatins; Methicillin-resistant Staphylococcus aureus; Microwave-assisted synthesis; Thiosemicarbazones.