Study on the Absorption Mechanism of Geniposide in the Chinese Formula Huang-Lian-Jie-Du-Tang in Rats.

Huang-Lian-Jie-Du-Tang (HLJDT) is a classical recipe for relieving fever and toxicity for thousands of years in China. Geniposide is one of the main components in HLJDT. The present study was conducted in order to investigate the differences of absorption of geniposide after oral administration of geniposide alone and HLJDT in rats. Pharmacokinetic differences of geniposide following oral administrations of pure geniposide and HLJDT were investigated in vivo. The absorption of geniposide in pure compound and HLJDT was evaluated using intestinal perfusion and Caco-2 models. The in vivo and in vitro studies showed good relevance and consistent results. The co-occurring components in HLJDT were found to promote the absorption of geniposide from the pharmacokinetic study in vivo, intestinal perfusion, and Caco-2 model. Geniposide had better absorption in the duodenum and jejunum from the intestinal perfusion model, which was mainly absorbed by passive diffusion. Verapamil influenced the transportation of geniposide, while EDTA did not, demonstrating that geniposide might be the potential substance of P-glycoprotein in intestinal perfusion and Caco-2 models. The absorption of geniposide was studied systematically to guide the design of the oral dosage of geniposide and HLJDT in clinical therapy.