Determination of chiral cathinone in fresh samples of Catha edulis

The main psychoactive compound in Khat is cathinone which consists of two enantiomers, S-(-)-cathinone being more stimulant than its R antipode. This study aimed to the enantioseparation and determination of these two stereoisomers in different parts of fresh Catha edulis. The samples were solvent extracted and cathinone was derivatized with menthyl chloroformate. The separation of the two diastereomeric derivatives was carried out by gas chromatography and showed an excellent resolution, while their structure was confirmed by mass spectrometry. The quantitative determination of both enantiomers showed a different distribution in various investigated parts of the plant, as shown in their enantiomeric excess. Unlike the results published in some previous articles, the current study confirmed the presence of both S and R cathinone in all parts of the fresh plant. The concentration of S-cathinone was higher in stems while its values were lower in leaves. The obtained concentrations were in the ranges 0.081-0.290 and 0.087-0.211 mg/g for S and R antipodes, respectively. Also, S-cathinone which is the most psychoactive stereoisomer showed an increasing concentration from lower to upper stems of the plant. The present study is the first quantitative investigation of the two cathinone enantiomers in different parts of fresh Catha edulis. (C) 2019 Elsevier B.V. All rights reserved.