CHIRAL GAS-CHROMATOGRAPHIC DETERMINATION OF EPHEDRINE-TYPE ALKALOIDS IN DIETARY-SUPPLEMENTS CONTAINING MA HUANG

Ma Huang is a traditional Chinese medicine derived from the aerial par ts of several Ephedra species (Ephedraceae), These plants produce (-)- ephedrine, (+)-pseudoephedrine, (-)-norephedrine, (+)-norpseudoephedri ne, (-)-N-methylephedrine, and (+)-N-methylpseudoephedrine. Racemic an d (-)-ephedrine, (+)-pseudoephedrine, and (+/-)-norephedrine (phenylpr opanolamine) are used clinically in the United States and are largely synthetic in origin, Current interest in Ma Huang is spurred by report s describing a ''thermogenic'' (calorie burning) effect provided by mi xtures of ephedrine, caffeine, and aspirin, Products providing the key thermogenic compounds from natural sources are available as dietary s upplements in retail outlets. Reports of potentially unsafe levels of the alkaloids, as well as possible fortification of Ma Huang-containin g products with synthetic Ephedra alkaloids, prompted the development of a chiral gas chromatographic (GC) method that allows determination of alkaloid patterns and identification of isomerically impure synthet ic alkaloids. Nine products were analyzed on a I cyclodextrin capillar y GC column, Identity of the alkaloids was verified by GC/mass spectro metry (MS) and GC/matrix isolation/Fourier transform infrared spectros copy, No synthetic isomers were found in the dietary supplements analy zed, Three products contained only one of the ephedrine-type alkaloids . One product that listed Ma Huang as an ingredient contained no detec table ephedrine-type alkaloid, In products containing measurable quant ities of these compounds, total alkaloid levels ranged from 0.3 to 56 mg/g.