Comparative pharmacokinetics of active anthraquinones ingredients after oral administration of Rhei Radix et Rhizoma and Niuhuang Jiedu Tablets to rats

The study aims to investigate different pharmacokinetic profilesof anthraquinones after oral administration of Rhei Radix et Rhizoma and Niuhuang Jiedu Tablets(NHJDT)in rats, respectively. Rats were administrated with 96 mg/kg of Rhei Radix et Rhizoma(1. 83 mg/kg of total anthraquinone, equivalent to 0. 28 mg/kg of rhein, 0. 30 mg/kg of emodin, 0. 81 mg/kg of chrysophanol, 0. 23 mg/kg of aloe-emodin and 0. 20 mg/kg of physcion)or 250 mg/kg of NHJDT(equal dose of total anthraquinone as Rhei Radix et Rhizoma, equivalent to 0. 33 mg/kg of rhein, 0. 38 mg/kg of emodin, 0. 71 mg/kg of chrysophanol, 0. 24 mg/kg of aloe-emodin and 0. 17 mg/kg of physcion), respectively. Followed by protein precipitation with methanol, the anthraquinones in plasma samples were determined by LC-MS/MS. The pharmacokinetic parameters were calculated by WinNonlin 7. 0. The c_maxof rhein were(121±103)and(474±251)μg/L, and the AUC0-twere(275±176)and(406±194)μg ·h/L for Rhei Radix et Rhizoma and NHJDT, respectively. The c_maxof chrysophanol isomer were(2 325±1 390)and(3 580±2 169)μg/L, and the AUC0-twere(8 170±2 661)and(8 856±4 023)μg ·h/L, respectively. Emodin in very low levels was only detected in rat plasma samples after oral gavage of NHJDT. The c_max, AUC and t1/2 of rhein, as well as Vd and CL of chrysophanol isomer were observed with a much increased degree in comparison with Rhei Radix et Rhizoma counterparts. However, much shorter t_maxwas found in NHJDT group. Therefore, NHJDT with co-existing components enhanced the absorption and influenced the pharmacokinetic behaviors of active ingredients in Rhei Radix et Rhizoma.