Comprehensive methodology for identification of Kratom in police laboratories

Leaves of Mitragyna speciosa Korth (Rubiaceae), commonly known as Kratom, are a popular narcotic product among recreational users all over the world. This product is widely distributed on the Internet and via smart-shops and is often a subject of examination in police laboratories. A major psychoactive component of Kratom is mitragynine which occurs exclusively in this species. The variety of combinations among M. speciosa products, cases of plant or chemical composition adulteration, give rise to a need to develop an universal methodology for identification of both, plant material and its active metabolite, mitragynine. Herein we propose a comprehensive authentication procedure which involves the microscopic analysis of plant material and inexpensive mitragynine detection using thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The developed methodology was successfully applied for the plant material investigation. Five samples of dried, shredded or powdered Kratom leaves, purchased via the Internet and one sample delivered by police have been identified.