Influence of co-administered danshensu on pharmacokinetic fate and tissue distribution of paeonol in rats.

Cortex Moutan (root bark of Paeonia suffruticosa Andrew) and Radix Salviae miltiorrhizae (root and rhizome of Salvia miltiorrhiza Bunge) are two herbs widely used in traditional Chinese medicine (TCM) to treat cerebrovascular and cardiovascular diseases. In clinical practice, these two herbs are prescribed together. Studies on the pharmacokinetic interaction between the active constituents of these two herbs (paeonol and danshensu, respectively) can provide substantial foundation for understanding its mechanism and empirical evidence to support the clinical practice. A simple and sensitive high-performance liquid chromatographic (HPLC) method coupled with ultraviolet detector was developed for determination of paeonol in plasma and different tissues (heart, liver, spleen, lung, kidney, and brain) of male Sprague-Dawley rats. When co-administering danshensu, the peak plasma concentration of paeonol was decreased (p < 0.01), the mean residence time (MRT) was prolonged (p < 0.001), the volume of distribution (Vd/F) was increased (p < 0.001), and the concentrations of paeonol in heart, brain, and lung were dramatically increased (p < 0.01 or p < 0.001), compared with these values for rats administered paeonol alone. The results showed that the co-administration of danshensu could alter pharmacokinetic fate and tissue distribution of paeonol in rats, especially in heart and brain, providing substantial foundation for the investigation of the impact of danshensu on paeonol in clinical applications.