Bioavailability enhancement of osthole after oral administration of Bushen Yizhi prescription extract to rats followed by Cnidium monnieri (L.) Cusson fruits extract in comparison to pure osthole at different doses.

Abstract Ethnopharmacological relevance Bushen Yizhi prescription (BSYZ) is a traditional Chinese compound prescription, which is commonly used in China for treating ShenXu and hypophrenia based on traditional Chinese medicine and Alzheimer's Disease according to modern Chinese medicine. Cnidium monnieri ( L. ) Cusson fruits (CM) is treated as the main herb of BSYZ, and its main active ingredient Osthole (OST) is considered as one of the major active ingredients of BSYZ. Even though OST plays an important role in the BSYZ its bioavailability is poor. In order to investigate whether the bioavailability of OST was influenced by BSYZ and CM extract, the comparative evaluations on pharmacokinetics of OST after oral administration of pure OST at different doses, CM and BSYZ extract were studied. Materials and methods 30 rats were randomly assigned to five groups and orally administered with pure OST at different doses (15, 75 and 150 mg/kg), CM (15 mg/kg OST) and BSYZ (15 mg/kg OST) extract. At different predetermined time points after administration, the concentrations of OST in rat plasma were determined by using the HPLC–UV method, and main pharmacokinetic parameters were investigated. Results The results showed that the pharmacokinetic parameters of OST were significantly different ( p 0→ t , AUC 0→∞ and C max of OST were significantly increased after oral administration of BSYZ extract, followed by CM extract, in comparison to pure osthole at different doses. Conclusions This present study indicated that the bioavailability of pure OST after oral administration was extremely low and it was dramatically enhanced because of the synergistic effect of the traditional Chinese Bushen Yizhi prescription.