Extraction and detection of mitragynine in Kratom leaves by high-performance liquid chromatography

Mitragyna speciosa, also known as Kratom, is an evergreen tree native to Southeast Asia that has been used in traditional medicine to relieve pain. The primary active alkaloid, mitragynine, found in Kratom leaves affects the same µ-receptor as the opioids. The potential effects of Kratom leaves on humans draw international concerns. The purpose of this study is to develop an efficient extraction method for mitragynine from dried Kratom leaves. Mitragynine was extracted from grounded Kratom leaves by liquid-liquid extraction and detected by an HPLC system with a C-18 column. The extracted sample was eluted with a mobile phase of 0.05% formic acid and acetonitrile (50:50, v/v), flow rate = 1.0 mL/min. Mitragynine was detected at 223 nm. The amount of mitragynine in four different strains of Kratom leaves was determined (wt/wt). Intra-day (n = 3) and inter-day(n = 3) studies show excellent precision with RSD < 2.1% and RSD < 3.6% respectively.