Preclinical Pharmacokinetic Interaction and Histopathological Analyses of Hedyotis diffusa on Sorafenib in Rats

Sorafenib is one of the most effective target therapeutic agents for patients with late-stage hepatocellular carcinoma. To seek possible alternative adjuvant agents to enhance the efficacy and improve the side effect of sorafenib, Hedyotis diffusa, one of the most prescribed phytomedicines for treating liver cancer patients in Taiwan, was evaluated in this work. We hypothesized that H. diffusa extract is a safety herb combination on the pharmacokinetic and pharmacodynamic effects of sorafenib. We designed treatments of sorafenib in combination with or without H. diffusa extract to examine its pharmacokinetic properties and effects on liver inflammation. The HPLC-photodiode-array method was designed for monitoring the plasma level and pharmacokinetic parameter of sorafenib in rat plasma. The pharmacokinetic results demonstrated that the area under the curve of sorafenib (10 mg/kg, p.o.) in combination with various doses of H. diffusa formulation (1, 3, and 10 g/kg, p.o.) for 5 consecutive days were 5560 ± 1392, 7965 ± 2055, 7271 ± 1371, and 8821 ± 1705 min μg/mL, respectively, no significant difference when compared with sorafenib treatment alone. Furthermore, the hepatic activity in rats administered with sorafenib with/without H. diffusa extract was quantitatively scored by modified hepatic activity index grading. H. diffusa extract in the range of 1 to 10 g/kg per day did not elicit significant herb-induced hepatotoxicity in rats, based on the histopathological study. Consequently, our findings provided positive safety outcomes for the administration of sorafenib in combination with the phytomedicine H. diffusa.