Binding of vinca alkaloid analogues to human serum albumin and to alpha 1-acid glycoprotein

The binding of a series of vinca alkaloid analogues having eburnane or indolo2,3-a]quinolizidine skeletons was studied with human serum albumin (HSA) by affinity chromatography and with alpha 1-acid glycoprotein by means of competition experiments. On HSA the binding occurs at the benzodiazepine-indole binding site via hydrophobic interaction and shows slight stereoselectivity preferring the trans isomers. The binding to alpha 1-AGP proved to be highly stereoselective in favour of the trans isomers having 3(S),16(R)eburnane or 1(R),12b(S)indolo2,3-a]quinolizidine absolute configurations.