Synthesis, molecular docking and biological evaluation of new steroidal 4H-pyrans

A series of new steroidal 4H-pyrans (4-6) have been synthesized from steroidal alpha, beta-unsaturated ketones (1-3). The products (4-6) were characterized by IR, H-1 NMR, C-13 NMR, MS and analytical data. The interaction studies of compounds (4-6) with DNA were carried out by employing gel electrophoresis, UV-vis and fluorescence spectroscopy. The gel electrophoresis pattern revealed that compounds (4-6) bind to DNA and also demonstrated that the compound 6 alone or in presence of Cu (II) causes the nicking of supercoiled pBR322. The compounds 4 and 5 bind to DNA preferentially through electrostatic and hydrophobic interactions with K-b values found to be 5.3 x 10(3) and 3.7 x 10(3) M-1, respectively, indicating the higher binding affinity of compound 4 towards DNA. The docking study suggested the intercalation of compounds in between the nucleotide base pairs. The cytotoxicity and genotoxicity of the newly synthesized compounds were checked by MIT and comet assay, respectively during which compound 6 showed potential behaviour. (C) 2013 Elsevier B.V. All rights reserved.