Effect of Radix Platycodonis and Radix Cyathulae in Xuefu Zhuyu Tang on tissue distribution of paeoniflorin in blood-stasis mice by HPLC: Experimental evidence on Shi ingredients in traditional formula compatibility

Xuefu Zhuyu Tang (XFZY), a famous formula in traditional Chinese medicine, has been demonstrated to show good therapeutic effects on diseases caused by blood stasis syndrome. Two of its eleven herbs, Radix Platycodonis and Radix Cyathulae, have been considered as Shi ingredients in the hierarchy of traditional formula compatibility and proven possessing synergistic properties that strengthen the formula's potency of activating blood circulation and resolving blood stagnation. However, its mechanism is still not clearly elucidated. In our previous study, we observed their effects on paeoniflorin pharmacokinetics of XFZY in rats. In this study, we continued by detecting and comparing their effect on the tissue distribution of paeoniflorin after oral administration of XFZY and its three variants (XFZY without Radix Platycodonis or/and Radix Cyathulae) in blood-stasis mice via HPLC assay. The results indicated that combining usage of Radix Platycodonis and Radix Cyathula increased the distribution of paeoniflorin in the lung and kidney and introduced the paeoniflorin into the liver, spleen and heart. It might explain their synergistic properties that strengthen the formula's effect of invigorating blood and dissolving stasis and provide experimental evidence to understand the pharmacological effects of Shi herbs in the hierarchy of traditional formula compatibility.