title: Microscopic and UPLC-UV-MS analyses of authentic and commercial yohimbe (Pausinystalia johimbe) bark samples.
abstract: Yohimbine is the major alkaloid found in the stem bark of yohimbe, Pausinystalia johimbe (Rubiaceae), an evergreen tree native to Africa. The objectives of the current study were to provide a detailed anatomy of yohimbe bark, as well as to determine the quantity of yohimbine in the raw yohimbe products sold online. Twelve commercial raw materials of yohimbe were analyzed by microscopic and ultra performance liquid chromatography-UV-MS methods. The study revealed that three samples were probably adulterated and four other samples contained various levels of impurities. Yohimbine was not detected in one sample, whereas its presence in other samples was found to be in the range 0.1-0.91%. The present work also provides a detailed anatomy of the stem bark of yohimbe, with light and scanning electron microscopy images, for proper identification and authentication.
authors.affiliation: School of Pharmacy, University of Mississippi, Oxford, MS, USA. vraman@olemiss.edu
authors.forename: Vijayasankar
authors.initials: V
authors.lastname: Raman
authors.forename: Bharathi
authors.initials: B
authors.lastname: Avula
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Galal
authors.forename: Yan-Hong
authors.initials: YH
authors.lastname: Wang
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D008853:Microscopy / Q000379:methods*; D032068:Pausinystalia / Q000737:chemistry*; D024301:Plant Bark / Q000737:chemistry*; D015016:Yohimbine / Q000032:analysis*
chemical_list: D015016:Yohimbine