flavokawain-a and kavain

Kava, the rhizomes and roots of Piper methysticum Forst, is a popular edible medicinal herb traditionally used to prepare beverages for anxiety reduction. Since the German kava ban has been lifted by the court, the quality evaluation is particularly important for its application, especially the flavokawains which were believed to be responsible for hepatotoxicity. Now, by employing two different standard references and four different methods to calculate the relative correction factors, eight different quantitative analyses of multicomponents by single-marker methods have been developed for the simultaneous determination of eight major kavalactones and flavokawains in kava. The low standard method difference on quantitative measurement of the compounds among the external standard method and ours confirmed the reliability of the mentioned methods. A radar plot clearly illustrated that the contents of dihydrokavain and kavain were higher, whereas flavokawains A and B were lower in different kava samples. Only one of eight samples did not detect flavokawains that may be related to hepatotoxicity. In summary, by using different agents as an internal standard reference, the developed methods were believed as a powerful analytical tool not only for the qualitative and quantitative of kava constituents but also for the other multicomponents when authentic standard substances were unavailable.

Topics: Chalcone; Chromatography, High Pressure Liquid; Dietary Supplements; Kava; Lactones; Phytotherapy; Plant Extracts; Plant Roots; Plants, Medicinal; Pyrones

Kava is a beverage made from the ground roots of the plant Piper Methysticum. Active compounds of Kava have previously been demonstrated to exert an antiproliferative effect through cell cycle arrest and promotion of apoptosis. Our aim was to investigate the in vitro effects of the main constituents derived from Kava on oral squamous cell carcinoma (OSCC) activity. Gas chromatography mass spectrometry (GCMS) was used to characterise the main constituents of two Kava preparations. Cell proliferation was assessed in two human OSCC cell lines (H400 and BICR56) and in normal oral keratinocytes (OKF6) treated with the identified Kava constituents, namely Flavokawain A (FKA), Flavokawain B (FKB), yangonin, kavain and methysticin using an MTS in vitro assay. Cell migration at 16 h was assessed using a Transwell migration assay. Cell invasion was measured at 22 h using a Matrigel assay. Cell adhesion was assessed at 90 min with a Cytoselect Adhesion assay. The two Kava preparations contained substantially different concentrations of the main chemical constituents. Treatment of malignant and normal oral keratinocyte cell lines with three of the identified constituents, 10 μg/ml FKA, 2.5 μg/ml FKB and 10 μg/ml yangonin, showed a significant reduction in cell proliferation in both H400 and BICR56 cancer cell lines but not in normal OKF6 cells. Remarkably, the same Kava constituents induced a significant reduction of OSCC cell migration and invasion. We have demonstrated, for the first time, that Kava constituents, FKA, FKB and yangonin have potential anticancer effects on OSCC. This highlights an avenue for further research of Kava constituents in the development of future cancer therapies to prevent and treat OSCC.

Topics: Cell Line, Tumor; Cell Movement; Cell Proliferation; Chalcone; Flavonoids; Gas Chromatography-Mass Spectrometry; Humans; Kava; Keratinocytes; Mouth Neoplasms; Plant Extracts; Pyrans; Pyrones; Squamous Cell Carcinoma of Head and Neck