Violacein/beta-cyclodextrin inclusion complex formation studied by measurements of diffusion coefficient and circular dichroism

The formation of inclusion compounds between violacein and beta-cyclodextri n was studied by diffusion and circular dichroism measurements. The present work was undertaken to explore the feasibility of the beta-cyclodextrin in reducing the toxicity and enhancing the antitumoral efficacy of violacein by forming an inclusion complex. The results of the two experiments are in good agreement, suggesting the formation of 1 : 1 and 1 : 2 complexes. The diffusion coefficient measurements enabled estimates of the sizes of the co mplexes involved. From the circular dichroism and computational calculation s it was possible to view a preference for inclusion of the most polar part of the molecule to form a 1 : 2 inclusion complex. We expect that this wor k proves the potential of these techniques to determining complex stoichiom etry.