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 β-cyclodextrin, and their interaction with bovine serum albumin in free and β-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.