The chemistry of khat.

This paper presents a review of literature on the chemical composition of khat (Catha edulis Forsk., Celastraceae). The effect of chewing fresh khat could not be explained satisfactorily by the action of d-norpseudoephedrine which was, for a long time, believed to be the only stimulant in khat. A comprehensive study on the chemical composition of khat was undertaken at the United Nations narcotics Laboratory with the aim of isolating and characterizing the principles of the fresh plant active on the central nervous system. This work resulted in the detection and isolation of cathinone, a phenylalkylamine characterized as (-)-alpha-aminopropiophenone. It is the main phenylalkylamine component of fresh khat, and pharmacological studies indicate that it may be the compound responsible for the characteristic stimulant activity and abuse potential of the plant. Some of its "decomposition" or transformation products, such as norpseudoephedrine, norephedrine, 3,6-dimethyl-2,5-diphenylpyrazine, and 1-phenyl-1,2-propanedione, have also been isolated and characterized.