Abstract 4629: Ultra performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS) method for analysis and pharmacokinetic study of flavokawain A, a novel chalcone from the kava plant, in mice
Authors: Xu Xia , Liu Zhongbo , Li Xuesen , Liu Shuman , Zi Xiaolin 
Published: June 2012

Abstract
Kava consumption in three Pacific Island Nations (i.e. Fiji, Vanuatu, and Western Samoa) was reported to inversely correlate with cancer incidences despite a high portion of smokers in their populations. We have recently identified flavokawains in kava extracts as causing strong antiproliferative and apoptotic effect in human bladder cancer cells. To examine the potential of flavokawain A, the predominant chalcone from kava extract, in chemoprevention of carcinogenesis, we established UPLC-MS/MS method for analysis and pharmacokinetic study of flaovkawain A in mice. Chromatographic separation of flavokawain A was achieved using an ACQUITY UPLC (Waters, UK) with a reversed-phase ACQUITY UPLCTM BEP C18 column (1.7μm, 2.1X 50mm, Waters). The UPLC was coupled to Micromass Quattro Micro LC/MS/MS triple quadrupole mass spectrometer (Mass Range: 2 ∼ 2000 m/z) with electrospray ionization (ESI) interface in positive mode. Flavokawain A was monitored at precursor ion with an m/z value of 314.9 and a fragment ion with a value at 181.14. For tissue distribution and pharamcokinetic studies, FVB/N mice were starved for 12 h, orally fed with flavokawain A (200mg/kg dose in 0.5% CMC-Na) and sacrificed after 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7 and 8 h. The plasma and desired tissues were collected and flavokawain A were extracted with acetonitrile. Parts of tissues were homogenized and then treated with sulfatase and β-glucuronidase followed by UPLC-MS/MS analysis. The pharmacokinetic parameters and the compartment model were analyzed by software Kinetica 4.4. The results showed that flavokawain A plasma concentration-time curve was fitted into the open two-compartment model. AUC value in plasma is 18.05 mg·h/L, Tmax value is 0.942h, and Cmax value is 0.7mg/L, T1/2 and CL values are 2.02 1/h and 145.07 L/h·kg. The peak levels of free flavokawain A were observed at 1.5h in liver, at 2.5 h in kidney and at 3.0h in bladder, accounting for 7.53µg/g, 7.5453µg/g and 1.35µg/g, respectively. The peak levels of sulfate and β-glucuronidate conjugates of flavokawain A were observed at 1h and 1.5h after administration in liver and kidney, with concentrations of 16.068µg/kg and 16.71µg/kg, respectively. In summary, compared to HPLC-UV, UPLC-MS/MS demonstrated short analytical time and enhanced sensitivity (a lowest detection limit can be up to about 0.5 ng) with capability to detect compounds in very limited amounts of tissues and with high specificity. UPLC-MS/MS therefore represents a very valuable tool for studying pharmacokinetics of natural products. In addition, our study clearly demonstrates the bioavailability of flavokawain A in plasma and its targeted organs, suggesting further studies to evaluate the chemopreventive efficacy of flavokawain A in different mouse cancer models.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4629. doi:10.1158/1538-7445.AM2011-4629