Rational eco-compatible synthesis and biological screening of new highly functionalized pyrido[2,3-a]carbazole derivatives: A novel class of antioxidant and anticancer agents

ABSTRACT

A solvent-free, one-pot, and operationally simple protocol was adopted to synthesize a new series of multifunctionalized pyrido[2,3-a]carbazole derivatives which were structurally characterized by FTIR, ¹H-NMR, ¹³C-NMR, and elemental analysis. The synthesized compounds were screened in vitro for their antibacterial activity and the compounds showed weak to moderate inhibition of bacterial growth. The antioxidant properties of the compounds were evaluated by their 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and total antioxidant capacity. Moreover, the cytotoxic effect of the compounds was examined on cancerous cell lines MCF-7 and A549 under in vitro conditions and the results showed that the compounds exhibited significant anticancer activity. Furthermore, the morphological changes and apoptosis induction were studied by inverted light microscopy, acridine orange/ethidium bromide, and 4′,6-diamidino-2-phenylindole dihydrochloride fluorescence microscopic analyses. The results indicated that among pyridocarbazole compounds, 2-ethoxy-8-chloro-4-(thiophen-2′-yl)-5,6-dihydro-11H-pyrido[2,3-a]carbazol-3-carboxamide 6g could be exploited as significant antioxidant and anticancer agents.

GRAPHICAL ABSTRACT

KEYWORDS:

• Antioxidant
• apoptosis
• cytotoxicity
• pyrido[2,3-a]carbazole
• solvent-free

Additional information

Funding

We would like to thank the University of Mysore, for NMR data. Financial support from “UGC-Emeritus fellowship” (Award NO.F.6-6/2015-17/EMERITUS-2015-17-OBC-7410/(SA II); dated 21.09.2015) for research, Dr. K. J. Rajendra Prasad gratefully acknowledged. We also thank University Grant Commission (UGC-SAP), New Delhi, for BSR—Senior Research Fellowship for further financial assistance and successful completion of this work.