Betz J M, White K D, der Marderosian A H
U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Washington, DC 20204, USA.
J AOAC Int. 1995 Sep-Oct;78(5):1189-94.
The bark of Pausinystalia yohimbe [K. Schumann] Pierre (Rubiaceae), long valued as an aphrodisiac in West Africa, recently has been promoted in the United States as a dietary supplement alternative to anabolic steroids for enhancement of athletic performance. As the number of yohimbe products on the retail market increases, concerns about their safety are raised because of the reported toxicity of yohimbine (the major alkaloid of the plant). Although plant materials are usually identified microscopically, we were unable to identify them in many of the products, because as their labels indicated, the products were mixtures of various botanicals or were bark extracts and contained little or no plant material. A method for extraction and capillary gas chromatographic (GC) separation of the alkaloids of P. yohimbe was, therefore, developed and used to analyze a number of commercial yohimbe products. The method involved solvent extraction and partitioning in chloroform-water followed by separation on a methyl silicone capillary GC column (N-P detection). Comparisons of chromatograms of extracts of authentic bark with those of commercial products indicated that, although many products contained measurable quantities of the alkaloid yohimbine, they were largely devoid of the other alkaloids previously reported in this species. Concentrations of yohimbine in the commercial products ranged from < 0.1 to 489 ppm, compared with 7089 ppm in the authentic material. Authentic bark has been reported to contain up to 6% total alkaloids, 10-15% of which are yohimbine. The possible presence of undeclared diluents in the products was indicated by peaks in product chromatograms but not in those of authentic bark.
育亨宾树（Pausinystalia yohimbe [K. Schumann] Pierre，茜草科）的树皮在西非长期以来一直被视为一种壮阳药，最近在美国作为一种膳食补充剂被推广，可替代合成代谢类固醇以增强运动表现。随着育亨宾产品在零售市场上数量的增加，由于育亨宾碱（该植物的主要生物碱）已报道的毒性，人们对其安全性产生了担忧。尽管植物材料通常通过显微镜进行鉴定，但我们无法在许多产品中鉴定出它们，因为正如其标签所示，这些产品是各种植物的混合物，或是树皮提取物，几乎不含或根本不含植物材料。因此，开发了一种提取和毛细管气相色谱（GC）分离育亨宾树生物碱的方法，并用于分析一些商业育亨宾产品。该方法包括溶剂萃取和氯仿 - 水分配，然后在甲基硅氧烷毛细管GC柱上进行分离（氮磷检测）。将正品树皮提取物的色谱图与商业产品的色谱图进行比较表明，尽管许多产品含有可测量量的生物碱育亨宾，但它们基本上不含该物种先前报道的其他生物碱。商业产品中育亨宾的浓度范围为<0.1至489 ppm，而正品材料中为7089 ppm。据报道，正品树皮含有高达6%的总生物碱，其中10 - 15%是育亨宾。产品色谱图中的峰表明产品中可能存在未申报的稀释剂，而正品树皮的色谱图中则没有。
