AbstractIntroductionCatha edulis (qat, khat, mirra) is a woody plant species that is grown and consumed in East Africa and Yemen for its stimulant alkaloids cathinone, cathine and norephedrine. Two Celastraceae species, in addition to qat, have been noted for their stimulant properties in ethnobotanical literature. Recent phylogenetic reconstructions place four genera in a clade sister to Catha edulis, and these genera are primary candidates to search for cathine and related alkaloids.ObjectiveDetermine if cathine or related alkaloids are present in species of Celastraceae other than Catha edulis.MethodsLeaf samples from 43 Celastraceae species were extracted in water followed by basification of the aqueous extract and partitioning with methyl‐t‐butyl ether to provide an alkaloid‐enriched fraction. The extract was derivatised in a two‐stage process and analysed using GC–MS for the presence of cathine. Related alkaloids and other metabolites in this alkaloid‐enriched fraction were tentatively identified.ResultsCathinone, cathine and norephedrine were not detected in any of the 43 Celastraceae species assayed other than Catha edulis. However, the phenylalanine‐ or tyrosine‐derived alkaloid phenylethylamine was identified in five species. Nine species were found to be enriched for numerous sterol‐ and terpene‐like compounds.ConclusionThese results indicate that cathine is unique to Catha edulis, and not the compound responsible for the stimulant properties reported in related Celastraceae species. Copyright © 2017 John Wiley & Sons, Ltd.