SummarySeven Kava lactones were extracted from Kava root using both pure and 15 % ethanol modified CO2. Most of the Kava lactones were extracted employing 100 % CO2 with an efficiency greater than 90 % relative to conventional solvent extraction using organic solvents. Extraction efficiency did not increase significantly when using 15 % ethanol-modified CO2 as an extraction fluid. Separation of extracted Kava lactones was obtained using various packed columns and methanolmodified CO2. An optimized separation was achieved using either an amino or protein C4 column at 125 atm and 80~ Semi-preparative separation of Kava lactones was also obtained using two columns connected in series.
The influence of clofibrate on the stereoconversion of fenoprofen (FPF) was studied in guinea pigs. This hypolipidaemic agent has been related to some biochemical changes in the liver leading to an increase in the chiral inversion process. Two groups of animals (n = 6 per group) were pretreated with oral doses of clofibrate (280 mg/kg per day) for three days and were then given (R)- or (S)-FPF (5 mg/kg, IV). The FPF enantiomers were extracted from the guinea-pigs' plasma using a solid phase procedure and analysed by HPLC with previous derivatization with L-leucinamide. Pretreatment with clofibrate increased the chiral inversion of (R)-FPF in favour of the pharmacologically active (S)-FPF enantiomer. Before this metabolic interaction can be applied to therapy with fenoprofen, the toxic effects of (S)-(+)-FPF on the gastrointestinal and renal tracts and the interference by (R)-(-)-FPF with the metabolism of lipids should be thoroughly evaluated.
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