Keywords: Kratom, medical plant, alkaloids, LC-MS

Abstract

In 2011, emergency rooms on theWest Coast had patients showing up with opiate/heroin withdrawal symptoms from Kratom. Mitragyna speciosa, or Korth (Thai name Kratom; Rubiaceae) is a medical plant native to Thailand and other Southeast Asian countries and is presently illegal in Thailand and other European countries [1]. In the United States, Kratom is readily available via the internet and local retail stores.

The leaves of Mitragyna speciosa consist of two primary active alkaloids: Mitragynine 66.2%, and 7 -hydroxy-7H-mitragynine 2.0%, and three indole alkaloids: Paynantheine 8.6%, Speciogynine 6.6%, and Speciociliatine 0.8%. Since mitragynine is one of the major constituent of Kratom, mitragynine is used as the marker compound for the identification and quantitation of Kratom in a variety of products.

This study describes methodology for the qualitative identification and quantitation of Kratom in dierent types of products such as but not limited to: powders, liquids, and spent-leaf materials. A quick methanolic based extraction procedure was used in combination with two instrument techniques: 1) GC/MS and/or LC-MS/MS for the initial screening and spectral confirmation of mitragynine in Kratom and quantitation via UPLC/PAD; 2) LC-MS/MS. Two dierent mass spectrometry systems were employed for confirmation/quantitation to permit flexibility within the regulatory laboratory for sample analysis.

A mitragynine solvent standard was used for the comparative identification of Kratom and quantitation was reported based on the level of mitragynine in the product tested. Due to the low concentration of the mitragynine stock standard (100 mug/mL) and the high level of mitragynine in the products tested, traditional spiking of the standard via a wet/dry spike into a negative control was not feasible. Solvent based calibration

curves were used for the quantitation of mitragynine in Kratom by UPLC/PDA and LC-MS/MS. Validation was performed by characterizing a Kratom product purchased via the internet. This positive control was extracted seven times over three days and analyzed by all three analytical techniques: GC/MS, LC-MS/MS and UPLC/PDA. The UPLC/PDA data demonstrated a mean value of 1.041% (n=21, 4.2%) and the LC-MS/MS 1.140% (n=14, 6.81%) for mitragynine in the positive control. This positive control was extracted and analyzed in duplicate with every analytical batch.

https://doi.org/10.21423/jrs-v03n02p001 (DOI assigned 8/7/2019)