Comprehensive chemometric analysis of b-carbolines alkaloids

FEDERICO A. O. RASSE-SURIANI; FERNANDO S. GARCÍA EINSCHLAG; ROSA ERRA-BALSELLS; FRANCO M. CABRERIZO

Villa Carlos Paz

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

Derivated of b-carboline (bC) alkaloids has were foundin a wide range of species [1-4]. In mammals, they have an exogenous (diet) [1] and endogenous origin (biosynthesis) [2]. In particular, N-methyl-bCs has been reported as potentialpathogenetic factors in Parkinson?s disease, inhibitors ofacetylcholinesterase enzyme, neuroprotective and neuron-differentiating agents,antimicrobial compounds, and DNA intercalators in vitro [3a-e]. So despite the established importance ofN-methyl-bCs and related bCs, the molecular bases of the mechanisms involved onthe above mentioned processes still need to be addressed. In this regard, adeep knowledge of fundamental aspects related to their spectroscopic, chemicaland photophysical properties represents a key starting point. It is known thatfor bCs the latter properties strongly depend on the chemical moleculestructure, as well as on the nature of the environment (solvent) and its pH [4]. In consequence, eachspecific bC derivative deservesspecial attention, particularly for better assessing the correlation betweenalkaloid acid-base species and their physico-chemical properties. Hence, we have systematically investigated photophysicalproperties of norharmane (nHo) andtheir N-methylated derivatives (Scheme 1), in aqueous solution, paying specialattention not only on the equilibrium and/or species dominant inphysiologically relevant pH-conditions but also under highly alkalineconditions. As in many cases the species involved have a highdegree of spectral overlap and the extraction of information is not possiblewith traditional analysis tools (univariate data), the use chemometric methods (multivariateanalysis techniques) was exploited for interpretation and analysis of thespectroscopyc data, providingqualitative and quantitative information about equilibria and species involved.bCs are naturally occurringsecondary metabolitesthat deserve to be explored in several fields of biology because they might represent an interestingalternative asfluorescent tracers endowed with unique photophysical properties. The results ofthe present work would contribute to understand the photophysical behavior of bCsin biological environments and, therefore, to further elucidate the roles played by these alkaloids in awide range of biological systems. In addition, this study also shows that multivariateanalysis provides a reliable tool for tracking bioactive compounds in naturalproduct extracts.