<jats:p>(S)-(+)-Nb-Methyltryptophan [(+)-abrine](1),(S)-(+)-Nb-methyltryptophan methyl ester(2),(S)-(+)-Nb,Nb-dimethyltryptophan methyl ester (3) and methyl (S)-(+)-2-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylate (6) have been isolated from the leaves of Gastrolobium callistachys Meissn. The structure of (6) has been confirmed by synthesis.