Five methods for the extraction of low‐polarity compounds from Mikania glomerata Spreng. (Compositae) leaves were compared: conventional maceration, maceration with sonication, Soxhlet, and supercritical fluid extraction using hexane (SFE‐hexane) or carbon dioxide (SFE‐CO2) as the extraction fluid. Evaluation of these methods by relating extraction yield to extraction time showed that SFE‐hexane was the most efficient method. SFE‐CO2 showed a lower yield, but significantly higher than conventional methods (maceration and Soxhlet). SFE‐hexane and maceration gave the highest yield of coumarin, while maceration under sonication gave the highest yield of kaurenoic acid. Among the further chemical constituents of Mikania glomerata leaves identified by high resolution gas chromatography–mass spectrometry were lupeol and lupeol acetate. © 1997 John Wiley & Sons, Ltd.

A capillary gas chromatography procedure for the determination of coumarin and kaurenoic acid in "guaco' (Mikania glomerata Spreng., Compositae) leaves is described. The method is shown to be sensitive and reproducible. The contents of coumarin and kaurenoic acid in a sample of "guaco' from Ribeirão Preto (Brazil) were found to be 4.40(±0.21) and 2.00 (±0.06) mg/g dried plant material, respectively. The method may have application in the analysis of "guaco' crude drug. © 1997 by John Wiley & Sons, Ltd.

Time for AdmissionT he recent telecast of the 0. J.Simpson trial has brought to the forefront the importance of forensic identification in legal proceedings, especially in criminal cases. Forensic science has become a key element in proving a defendant's guilt or innocence. In the 0. J. Simpson trial, the question was not one of the admissibility of the expert testimony regarding the existing DNA testing procedure and the resulting conclusions but rather what weight the jury would give these results.The Federal Rules of Evidence, which are standardized and binding on all U.S. District Courts, are applied to offers of evidence, including testimony, to ensure that juries hear and ultimately consider only admissible material and relevant evi- Recent changes in the Federal Rules of Evidence affect the admissibility of scientific evidence in court