Study on the Plasma Protein Binding Rate and Compatibility Regularity of the Constituents Migrating to Blood of Simiao Yong’an Decoction

Objective: To study the compatibility regularity of Simiao Yong’an decoction by determining the plasma protein binding rate with the constituents in Simiao Yong’an decoction and to preliminarily clarify the effects of the compatibility on the plasma protein binding rate of different components. Methods: Based on the equilibrium dialysis method, high-performance liquid chromatography was used to determine the contents of six constituents, which were divided into a single group and combination groups, in Simiao Yong’an decoction in the internal and external dialysis solutions. The obtained plasma protein binding rate through calculations was an index to evaluate the binding of the above components to plasma protein in different conditions. Results: Harpagide, harpagoside, sweroside and loganin showed low plasma protein binding rates, ferulic acid exhibited a moderate plasma protein binding rate, and glycyrrhizic acid showed a high plasma protein binding rate. The compatibility study showed that glycyrrhizic acid promoted the binding of ferulic acid to plasma protein. Glycyrrhizic acid and ferulic acid were the key compounds to promote the binding of harpagide to plasma protein. Glycyrrhizic acid, harpagide, harpagoside and loganin had a significant inhibitory effects on the binding of sweroside to plasma protein. The plasma protein binding capacities of harpagoside and loganin were reduced by the other five constituents. Glycyrrhizic acid had the strongest plasma protein binding effect, and the binding effect was not affected by other components. Conclusions: This study explores the effects of compound compatibility on effective components from the perspective of plasma protein binding by high-performance liquid chromatography combined with the equilibrium dialysis method, and lays a foundation for clarifying the compatibility rule of Simiao Yong’an decoction and also provides a new idea for the study of the compatibility of traditional Chinese medicine formulas.