Synthesis and biological evaluation of novel 3-O-tethered triazoles of diosgenin as potent antiproliferative agents

Diosgenin, a promising anticancer steroidal sapogenin, was isolated from Dioscorea deltoidea. Keeping its stereochemistry rich architecture intact, a scheme for the synthesis of novel diosgenin analogues was designed using Cu (I)-catalysed alkyne-azide cycloaddition in order to study their structure-activity relationship. Both diosgenin and its analogues exhibited interesting anti-proliferative effect against four human cancer cell lines viz. HBL-100 (breast), A549 (lung), HT-29 (colon) and HCT-116 (colon) using [3-(4,5-dimethylthiazoly1-2)-2,5-diphenyltetrazoliumbrornide] (MU) assay. Among the synthesized analogues, Dgn-1 bearing a simple phenyl R moiety attached via triazole to the parent molecule was identified as the most potent analogue against A549 cancer cell line having IC50 of 5.54 mu M, better than the positive control (BEZ-235). Dgn-2 and Dgn-5 bearing o-nitrophenyl and o-cyanophenyl R moieties respectively, displayed impressive anti-proliferative activity against all the tested human cancer cell lines with IC50 values ranging from 5.77 to 9.44 mu M. The structure-activity relationship (SAR) revealed that the analogues with simple phenyl R moiety or electron withdrawing ortho substituted R moieties seem to have beneficial impact on the anti -proliferative activity. (C) 2016 Elsevier Inc. All rights reserved.