Pharmacokinetics and organ distribution of diarylheptanoid phytoestrogens from Curcuma comosa in rats

Curcuma comosa is widely used as a traditional herbal medicine for gynecological diseases in South East Asia. Previous studies reported that it has phytoestrogenic activity, and several diarylheptanoids were found to be the active constituents. In this study, the pharmacokinetics profile and organ distribution of three active compounds of C. comosa hexane extract were investigated. Rats were separately administered C. comosa hexane extract intravenously at the dose of 125 mg/kg and orally at the doses of 125 and 250 mg/kg body weight, after which blood and target organs were collected at specified time intervals from 0 to 24 h. HPLC was used to measure the concentration of three major compounds, (6E)-1,7-diphenylhept-6-en-3-one (DPH1), (4E,6E)-1,7-diphenylhepta-4,6-dien-3-ol (DPH2), and (6E)-1,7-diphenylhept-6-en-3-ol (DPH3), which were found to be present in the blood and tissues and were subsequently used as markers. In the intravenous study, the volumes of distribution (V(d)) were 1.06, 8.57, and 6.56 L/kg and clearance values (CL(s)) were 0.28, 5.56, and 3.39 L/kg/h for DPH1, DPH2, and DPH3, respectively. After oral administration, the three major compounds of both doses reached a maximum systemic concentration at 2 h with maximum concentration (C(max)) of 0.85, 0.17, and 0.53 mg/L for the lower dose and 1.46, 0.17, and 0.61 mg/L for the higher dose. The bioavailabilities were 31.2, 24.01, and 31.56% for lower dose and 22.61, 17.66, and 17.73% for higher dose with a terminal half-life (t(1/2)) of 10.86, 6.3, and 4.62 h for lower dose and 3.85, 2.77, and 2.10 h for higher dose for DPH1, DPH2, and DPH3, respectively. These three major compounds are all found distributed in the brain, liver, kidneys, ovaries, and uterus after oral and intravenous administration and their related pharmacokinetic parameters are described. This study provides the essential pharmacokinetic data for diarylheptanoid phytoestrogenic compounds of C. comosa extract which are required for clinical dose and dosage design.