title: Comparison of three chromatographic techniques for the detection of mitragynine and other indole and oxindole alkaloids in Mitragyna speciosa (kratom) plants.
abstract: Leaves of the Southeast Asian plant Mitragyna speciosa are used to suppress pain and mitigate opioid withdrawal syndromes. The potential threat of abuse and ready availability of this uncontrolled psychoactive plant have led to the need for improved analytical techniques for the detection of the major active components, mitragynine and 7-hydroxymitragynine. Three independent chromatographic methods coupled to two detection systems, GC with MS, supercritical fluid chromatography with diode array detection, and HPLC with MS and diode array detection, were compared for the analysis of mitragynine and other indole and oxindole alkaloids in M. speciosa plants. The indole alkaloids included two sets of diastereoisomers: (i) paynantheine and 3-isopaynantheine and (ii) mitragynine, speciogynine, and speciociliatine. Two oxindole alkaloid diastereoisomers, corynoxine and corynoxine B, were also studied. The HPLC and supercritical fluid chromatography methods successfully resolved the major components with slightly different elution orders. The GC method was less satisfactory because it was unable to resolve mitragynine and speciociliatine. This separation was difficult by GC with a liquid stationary phase because these diastereoisomers differ only in the orientation of an interior hydrogen atom. The observed lack of resolution of the indole alkaloid diastereoisomers coupled with the likeness of the mass and tandem mass spectra, calls into question proposed GC methods for the analysis of mitragynine based on solely GC with MS separation and identification.
authors.affiliation: National Center for Natural Products Research, University of Mississippi, University, MS, USA.
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Carrell
authors.forename: Zulfiqar
authors.initials: Z
authors.lastname: Ali
authors.forename: Bharathi
authors.initials: B
authors.lastname: Avula
authors.forename: Cristina
authors.initials: C
authors.lastname: Avonto
authors.forename: Jon F
authors.initials: JF
authors.lastname: Parcher
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
mesh_terms: D000470:Alkaloids / Q000032:analysis*; D002845:Chromatography / Q000379:methods*; D000077743:Diterpene Alkaloids; D007211:Indoles / Q000032:analysis*; D032065:Mitragyna / Q000737:chemistry*; D000078183:Oxindoles; D010936:Plant Extracts / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry; D046948:Secologanin Tryptamine Alkaloids / Q000032:analysis*
chemical_list: D000470:Alkaloids; D000077743:Diterpene Alkaloids; D007211:Indoles; D000078183:Oxindoles; D010936:Plant Extracts; D046948:Secologanin Tryptamine Alkaloids; C022960:2-oxindole; C001801:mitragynine
keywords: Chromatography and mass spectrometry; Indole alkaloids; Mitragyna speciosa; Mitragynine; Oxindole alkaloids