(1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) is a β-carboline indole alkaloid naturally occurring in plants, foods, insects, and endogenously in mammals and humans. It exerts antioxidant and antithrombotic properties. MTCA is thought to be a possible causative substance of eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan.

Trifluoromethylphenylpiperazine (TFMPP) acts on serotonin receptors 5-HT1A, 5-HT1B, 5-HT1D, 5-HT2A and 5-HT2C and functions as a full agonist at all sites except the 5-HT2A receptor, where it acts as a weak partial agonist or antagonist. In addition, TFMPP binds to the sodium-dependent serotonin transporter, SERT and evokes the release of serotonin. Besides was shown, that the N-Benzylpiperazine/TFMPP combination produced effects, which crudely mimic those of MDMA, commonly known as ecstasy. The neurophysiological effects of TFMPP in humans was also studied and was shown that TFMPP may affect transmitter systems involved in speeding of interhemispheric communication in the male brain.