Pharmacokinetics of characteristic effective ingredients from individual and combination Shaoyao and Gancao treatement in rats using HPLC fingerprinting

Shaoyao-Gancao decoction, a traditional Chinese formulation composed of Paeoniae Radix and Glycyrrhizae Radix, is commonly used to relieve abdominal pain. In this paper, the compatibility rationality of this decoction was investigated. Shaoyao-Gancao decoction, Shaoyao decoction and Gancao decoction were orally administered to rats, respectively. Blood samples were collected at pre-determined times after administration and analyzed by high-performance liquid chromatography (HPLC). The pharmacokinetic parameters of characteristic peaks were analyzed and the statistical significance of the obtained parameters was determined. Paeoniflorin (12.0 min) and compounds at retention times of 4.7 and 5.2 min were all significantly higher in the Shaoyao-Gancao decoction than in the Shaoyao decoction (P < 0.05). In contrast, in the Gancao decoction, the compound at a retention time of 14.6 min was significantly lower than in the Shaoyao-Gancao decoction (P < 0.01). However, the compounds at retention times of 17.1 and 18.1 min were significantly higher in the Gancao decoction than in the Shaoyao-Gancao decoction (P < 0.05). These results indicate that poor compatibility of the compounds in the Shaoyao-Gancao decoction could result in poor absorption. The compatibility of the component compounds of the Shaoyao-Gancao decoction was revealed in the pharmacokinetic characteristics of the decoction. Generally, the absorption of Shaoyao components was increased in the Shaoyao-Gancao decoction, while the absorption of Gancao components was time dependent. In the Shaoyao-Gancao decoction, the increased absorption of some Shaoyao components may be related to a reduction in absorption of some Gancao components.