Occurrence of bufotenine in the Osteocephalus genus

Costa, T.O.G.(2,3), Brito, J.P.(1), Morales, R.A.V.(1), Gordo, M.(3), Pinto, A.C.(2), Bloch Jr.,C.(1)

(1)Embrapa - Recursos Genéticos e Biotecnologia, (2)UFRJ - Universidade Federal do Rio de Janeiro, (3)UA, Universidade do Federal do Amazonas.

Bufotenine (5-hydroxy-N,N-dimetyltryptamine) is a tryptophan derived indolealkylamine widely distributed in Leguminosaeplant family and vertebrate animals, especially mammals and amphibians from genus Bufo. In humans, this molecule is associated with brain diseases and acts as a potent hallucinogenic factor, showing activity similar to LSD upon interaction with the 5HT₂ receptor. This study investigates the presence of bufoteninein the skin secretion of three amphibians’ species (O. taurinus, O. oophagusand O. langsdorf) from the Amazon and Atlantic rain forests using RP-HPLC, ESI-MS/MS and NMR. The skin extracts were obtained by mild electrical stimulation, collected in Milli-Q water, and were later frozen, and lyophilized. The water-soluble fractions from the crude extract were fractionated by RP-HPLC, using a semi-preparative C₁₈ column in a linear acetonitrile gradient with 0,1% of trifluoracetic acid. Bufotenine fractions eluted at 21,5 min and were submitted to a further purification step using analytical RP-HPLC. ESI-MS analysis of the purified fractions produced a single ion of 205,16 Da (M+H⁺) and a fragmentation pattern, characterized by the daughter ions: 160,1 Da (M+H⁺) corresponding to the loss of C₂H₇N, and 58,2 Da (M+H⁺) corresponding to C₃H₈N, obtained upon cleavage of the amine ring substitution between methylenes.  NMR (400MHz) spectra in conjunction with HSQC experimental data confirmed the bufotenine identity. This is the first description of bufotenine in the Osteocephalus genus. These data associated with the geographical distribution of the studied species, so far strongly supports the theory that indole alkaloids are widely spread among anuran families as a chemical defense system.  

CORRESPONDENCE TO:

Túlio de Orleans Gadelha Costa, Rua Senador Vergueiro, 35/1101, Rio de Janeiro, RJ, CEP: 22230-001, Brasil, Email: tulio30@aol.com