采用核磁共振波谱技术(NMR)研究小檗碱与牛血清白蛋白(BSA)的相互结合作用.比较不同浓度小檗碱在一定浓度的BSA溶液中的化学位移、弛豫时间和扩散系数的变化情况.研究表明,小檗碱环上芳香质子与BSA的结合作用较强,其它烷基质子与BSA结合作用较弱;BSA的结合使得小檗碱各个质子的1HT1弛豫时间明显减少,质子在溶液中运动受限;小檗碱与BSA相互作用的饱和浓度之比为60:1;根据自扩散系数拟合可以得到两者解离常数为0.44 mmol/L;结合位点数为22.本研究为临床安全、合理使用小檗碱,以及开发改良小檗碱类似药物提供实验依据.%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 anti-bacterial 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 sug-gests 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.
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