Avaliação da variabilidade química dos alcaloides de Erythrina velutina Willd e otimização do método extrativo por delineamento experimental

Abstract

The genus Erythrina L., belonging to the family Fabaceae (Leguminosae), comprises about 130 species distributed in several countries. In short, theyare mostly employed in the recovery of devastated areas, and notably, their traditional use involves infection control, liver treatments, in addition to its wide use as an anxiolytic/tranquilizing agent. At this juncture, the species Erythrina velutina willd. (mulungu) is found, in which it has among the metabolites produced, the tetracyclic alkaloids (erythrin) in a comprehensive way, which through the polycyclic structure stand out in the field of research through the biological activities identified essentially in the central nervous system (CNS). The wide chemical variability present in the entire genus are remarkable, but there is a lack of official records, which conditions the commercialization of different species with the same nomenclature. In this context, the present work aimed to evaluate the chemical variability in E. velutina in different collection sites and pharmacogens, optimizing the extractive method through the experimental design. For the development of the study, samples were collected in three different localities of Chapada Diamantina: municipalities of Boninal, Mulungu and the district of Barriguda. The plant material was extracted, and the method was developed by high- performance liquid chromatography coupled with a diode detector (HPLC/DAD). The mobile phase was composed as water:triethylamine (99.9:0.1) adjusted at pH 3.0 with trifluoroacetic acid (phase A), and acetonitrile:triethylamine (99.9:0.1) as phase B in gradient elution mode. The analytical profile exhibited a certain congruence in the peaks identified in flower samples in the study trees with high intensity, except for the Mulungu tree. However, the stem bark samples showed promising results in the terms of intensity and similarity. Then, the chemical characterization by GC-MS revealed data about the chemical markers present in the different collection sites, in which erysodine, erythrinin, erysothrin/dienoid isomer, erythralin, erysothine, and especially eysovine were identified, which was detected in all the pharmacogens analyzed. Finally, the extractive process was optimized through the Box-Behnken strategy, and the optimal point generated was defined with 3.63 hours, 0,59mm of particle size and 126.06 plant:solvent ratio. In summary, the methodologies employed were effective to identify the chemical profile of the E. velutina alkaloids collected in the state of Bahia, reaffirming the ethnobotanical data of the use of stem bark in most treatments, as a result of the high quantify of the investigated components and chemical variability.