3,4-Dihydro-b-carboline alkaloids as potential endogenous photosensitizers

FERNANDO D. VILLARRUEL; FRANCO M. CABRERIZO; ROSA ERRA-BALSELLS; M. PAULA DENOFRIO

Villa Carlos Paz

Encuentro; XIII Encuentro Latinoamericano de Fotoquímica y Fotobiología (XIII ELAFOT); 2017

B-carbolines (bCs) represent a family of naturallyoccurring alkaloids and their presence has been confirmed in a vast range ofphylogenetically distant species, i.e., Rhizaria,Alveolata,Amoebozoa,Stramenopiles,Opisthokonta,Archaeplastida,Urochordataand Arthropoda.From the chemical point of view, bCs comprise both full-aromatic and partiallyhydrogenated (such as 3,4-dihydro- and 1,2,3,4-tetrahydro-) heterocyclic structures.In particular, harmaline and harmalol are the most representative and naturallydistributed dihydro-bC derivatives. In terms of its chemical structure, harmineand harmol represent the corresponding full-aromatic structures (Scheme 1).During the last decade, the photochemistry andphotodynamic properties of some full-aromatic bCs have been deeply studied. Ithas been well documented that these properties strongly depend on the chemical nature ofthe bC substituent [1-6]. However, the information available in theliterature regarding the chemical properties of photo-excited 3,4-dihydro- and1,2,3,4-tetrahydro-bCs, is still negligible or null and, when available, issomehow contradictory [7].In thepresent work, we have investigated the photochemical behavior of two particular3,4-dihydro-bCs, harmaline and harmalol, in aqueous solutions under different O2concentrations. Also, we examine the capability of these bCs to photoinduce damagein cell-free DNA. Results obtained arecompared with data recorded for the corresponding full-aromatic βC,harmine and harmol respectively.