Effect of quercetin on the acyclovir intestinal absorption

OBJECTIVE: To study the effect of quercetin on acyclovir intestinal absorption. METHODS: The everted gut sac and in vitro intestinal absorption tests were performed. The acyclovir transport quantity was determined by HPLC method. RESULTS: The everted gut sac study showed that quercetin significantly inhibited the function of intestinal P-glycoprotein P-gp . The acyclovir transport quantities from mucosa to serosa space, which incubated with 5, 10, 80 mg/L quercetin solution or 10 mg/L verapamil solution, were increased 0.3, 0.6, 1.0 and 1.0-fold higher than acyclovir alone, respectively. The transport quantity caused by inhibition of intestinal P-gp function fitted with Boltzmann equation. The in vitro intestinal absorption test indicated that the transported acyclovir from serosa to mucosa, incubated with 2, 5, 10 mg/L quercetin solution, was significantly decreased compared with acyclovir alone. CONCLUSION: Quercetin can enhance acyclovir intestinal absorption by inhibiting the function of P-gp.