New indole-7-aldehyde derivatives as melatonin analogues; synthesis and screening their antioxidant and anticancer potential.

Over the last decade, there has been substantial interest in the use of melatonin (MLT) and MLT-like compounds in the treatment of several diseases. MLT can scavenge different reactive oxygen species and can also stimulate the synthesis of antioxidant enzymes. Our ongoing study relies on changing the groups in the different modifiable sites of the indole ring to increase the antioxidant activity. In this study a new approach for substitution of indole ring as indole based MLT analogue was proposed. We report the synthesis and characterization of a series of new indole-7-aldehyde hydrazide/hydrazone derivatives as indole-based MLT analogues. Anticancer potential of the compounds were evaluated both by their antioxidant and CYP1 inhibitory activities. In vitro antioxidant capacity of the compounds was investigated both in a cell-based (DCFH assay) and a cell-free (DPPH assay) assay. Potential inhibitory effects of the compounds on CYP1 catalytic activity were investigated via EROD assay. Cytotoxic activity of the compounds was further evaluated by the MTT assay in CHO-K1 cells. MLT analogues having an o-halogenated aromatic moiety exhibited effective antioxidant properties without having any cytotoxic effect. In conclusion, MLT derivatives represent promising scaffolds for discovery of effective antioxidant agents.

Antimicrobial evaluation of indole-containing hydrazone derivatives.

There has been an increasing importance of drug-resistant pathogens in clinical microbiological and antibacterial research. Indoles and hydrazone-type compounds constitute important classes of compounds in the search for effective agents against multidrug-resistant microbial infections. In this study a series of 1-methylindole-3-carboxaldehyde hydrazone derivatives were evaluated for their in vitro antimicrobial activities using the two-fold serial dilution technique against Staphylococcus aureus, methicillin-resistant S. aureus, methicillin-resistant S. aureus isolate, Escherichia coli, Bacillus subtilis, and Candida albicans. The minimum inhibitory concentration (MIC) of the test compounds and the reference standards sultamicillin, ampicillin, fluconazole, and ciprofloxacin was determined. All compounds possessed a broad spectrum of activity having MIC values of 6.25-100 microg/ml against the tested microorganisms. Aromaticity and disubstitution of the phenyl ring with especially fluorine and chlorine atoms were found to be significant for the antimicrobial activity