Albumin Binding and Anticancer Studies of trimethyl-, and triphenylstannyl (4R)-4-((3R,5R,10S,12S,13R,17R)-3,12-dihydroxy- 10,13-dimethylhexadecahydro-1Hcyclopenta[a]phenanthren-17-yl)pentanoate)

Trimethyl- (1) and triphenyl tin (2) derivatives of sodium (R)-4-{(3R,5R,8R,9S,10S,12S,13R,14S,17R)-3,12-dihydroxy-10,13-dimethyl-hexadecahydro-1H-cyclopenta[a]phenanthren-17-yl} pentanoate (sodium deoxycholate) were synthesized by refluxing sodium deoxycholate with the corresponding triorganotin(IV) chlorides in equimolar ratio. The two compounds were characterized by elemental analysis, infrared spectroscopy, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopy. Base on FT-IR spectra, Δν values anticipated bridging or chelating behavior of the ligand. Both the compounds gave a trigonal bipyramidal geometry in the solid state and tetrahedral geometry in solution. The interaction of (1) and (2) with bovine and human serum albumin was investigated at two different temperatures (298 and 310K) utilizing fluorescence quenching experiments. Fluorescence quenching constants were determined from the Stern-Volmer equation. Both the compounds bind with Bovine serum albumin (BSA) and Human serum albumin (HAS) through a dynamic quenching pathway. Compound 1 binds with BSA and HSA at two temperatures with an association constant of 3.9 x 10⁴ and 8.0 x 10⁴ at 298K and 9.9 x 10⁴ and 1.02 x 10⁴ at 310K, respectively. Similarly, compound 2 binds with BSA and HSA with quenching constants of 3.9 x 10⁴ and 1.8 x 10⁴ at 298K and 1.4 x 10⁴ and 4.5 x 10⁴, respectively. The synchronous fluorescence spectrum of compounds suggested that the tryptophan residues contribute significantly to intrinsic fluorescence quenching.