Interaction of Curculigosides and Their β-Cyclodextrin Complexes with Bovine Serum Albumin: A Fluorescence Spectroscopic Study

Curculigosides A and B, two of the phyto-constituents of the medicinal plant Curculigo orchioides gatern, were isolated. The binding properties of these curculigosides with beta-cyclodextrin, and their interaction with bovine serum albumin in free and beta-cyclodextrin-complexed forms, were studied using fluorescence spectroscopy. The stoichiometry and binding constants of these complexes together with their binding modes are reported. Both of the curculigoside-cyclodextrin complexes are found to bind more weakly to the bovine serum albumin molecule than their free forms. The difference in the binding strengths of curculigoside A and curculigoside B with cyclodextrin makes a difference in their binding with bovine serum albumin.