Determinação quantitativa por CLAE-DAD de salicilato de metila e atividade antinociceptiva em espécies do gênero Polygala (Polygalaceae) ocorrentes no semiárido e cultivadas

Abstract

In the pharmaceutical field, plants and plant extracts are still highly relevant, owing to the use of their active compounds as prototypes for drug development. Studies show that species of the genus Polygala produce methyl salicylate, which is a component of some analgesic. To date, there is just one scientific work describing the quantification of this compound by HPLC-DAD in species of Polygalaceae. It is from our research group, but only with Polygala decumbens. So, this work describes the quantitative determination of methyl salicylate, employing HPLC-DAD, in seventeen species of Polygalaceae of Brazil semiarid region, collected or cultivated, besides the determination of antinociceptive activity of one of the species with higher levels of the substance under analysis through application of the abdominal contortions and hot plate tests. Significant discrepancies were found in the concentration of methyl salicylate, varying from values below the limit of quantification (14,1 µg/g) to values greater than the highest concentration point of the calibration curve (126,9 µg/g). P. decumbens was the unique species that survived the greenhouses cultivation conditions and its analysis showed that the concentration of methyl salicylate was reduced to values below the limit of quantification and detection in aerial parts, when compared with values obtained on specimens collected in the field. On the other hand, there were no significant alteration in the values obtained from the roots collected in the field and cultivated (99,43±5,93 e 98,24±2,81 µg/g, respectively). The evaluation of the antinociceptive activity showed that the crude extract of P. boliviensis when administered orally, has reduced nociception in both abdominal contortions and hot plate tests in up to 382.79% and 93.59% respectively. Finally, this study supports other data in the literature, showing the importance of the species of Polygalaceae as a source of variety of compounds with potential biological activity.