| || || Prasad, Sunny Yurendra|
| || || Separation and quantitation of kava lactone yielding precursor(s) from Piper methysticum Forst|
Author:Prasad, Sunny Yurendra
Institution: University of the South Pacific.
Call No.: pac In Process
Copyright:Under 10% of this thesis may be copied without the authors written permission
Abstract: Kava lactones are the biologically active ingredients in.Piper methysticum Forst. (kava plant)Apart from their existence in free forms, it was found that a portion of these biologically active kava lactones exist in bound forms. Work presented in this thesis reports for the first time the existence of kava lactone-yielding precursors for desmethoxyyangonin, yangonin and kavain in dried kava roots. After the removal of all free desmethoxyyangonin, yangonin and kavain from the polar root extracts, a second crop of desmethoxyyangonin, yangonin and kavain was observed when subjected to various aqueous-pH reflux and enzymatic hydrolyses. This result suggests the occurrence of kava lactone-yielding precursor(s)Further purification of the delactoned residue using semi-preparative HPLC resulted in separation of six chromatographically distinguishable precursor-rich fractions. Each fraction when boiled in pH 5-buffered water yielded different ratios of desmethoxyyangonin, yangonin and kavain. This suggests the possible existence of multiple precursors for each kava lactone, which are structurally/chemically different. Furthermore, 1HNMR spectroscopy of the fractions provided evidence for glycosides. Due to the initial extraction of the kava sample with water, it is believed that the kava extract could to be rich in glycosides and from the results obtained using 1HNMR spectroscopy it was evident that the precursors of kava lactones are glycosides, however further purification was necessary for structural elucidation which was beyond the scope of this research.