Pharmacokinetics, Tissue Distribution and Protein Binding Studies of Chrysocauloflavone I in Rats

Chrysocauloflavone I, an unfrequent biflavonoid, was purified from Selaginella doederleinii in this study. It showed cytotoxic effects on three human cancer cells, NCI-H1975, A549, and HepG-2, in vitro. In silico assessment of the physicochemical properties was performed for predicting the permeability and intestinal absorption of the tested compound. Subsequently, a rapid, sensitive, and specific high-performance liquid chromatography method was developed for determination of the compound in different biological samples to ascertain the pharmacokinetics, tissue distribution, and protein binding profiles of this active ingredient in rats. After intravenous dosing of chrysocauloflavone I at different levels (10 and 20 mg/kg), the elimination half-life was approximately 85 min, and the AUC0-∞ increased with the dose from 148.52 mg/L × min for 10 mg/kg to 399.01 mg/L × min for 20 mg/kg. After single intravenous dosing (20 mg/kg), chrysocauloflavone I was detected in all tissues studied with higher levels in the heart, blood, and lungs. The results of equilibrium dialysis indicated a very high protein binding degree (over 97%) for chrysocauloflavone I. After intragastric administration of 100 mg/kg chrysocauloflavone I to rats, no parent drug was detected in the rat plasma. This is the first report of the favorable bioactivities, plasma pharmacokinetics, tissue distribution, and protein binding profiles of the rare biflavone chrysocauloflavone I.