Nuclear Magnetic Resonance Studies on Interactions of Berberine and Bovine Serum Albumin
1H nuclear magnetic resonance chemical shift,relaxation time and diffusion coefficient measurements were carried out to study the interaction on the affinity binding of Berberine,an antibacterial drug,to bovine serum albumin(BSA).The results showed that the protons of aromatic ring of Berberine were more favorable to form Berberine-BSA complex than those of aliphatic groups.BSA combination resulted in significantly decrease in the relaxation time of Berberine protons,which suggests that the motion of these protons were limited in aqueous solutions.The saturation concentration ratio of Berberine to BSA is 60 ∶ 1 according to the measurements of chemical shift and relaxation time.The apparent dissociation constant was 0.44 mmol/L and the binding sites of Berberine molecules on BSA was 22 fitted from the self-diffusion measurements.This study is of great importance for the safe and rational use of Berberine in clinic,and development of improved Berberine analogs.