| dc.description.abstract | Cuphea carthagenensis (Jacq.) MacBride Lythraceae is popularly known as sete-sangrias. It is traditionally employed to treat cardiovascular diseases, among other conditions. It was not found any research about the relationship between quantitative chemical composition and biological activity. Therefore the goal of the present work was to evaluate qualitative and quantitative chemical composition of the species and its potential vasodilating activity, along with to define chemical markers and develop analytical methods. The extraction of C. carthagenensis aerial parts afforded the aqueous (EA) and ethanol (EB) extracts, whereas fractionation of EB furnished n-BuOH, aqueous soluble and aqueous insoluble in MeOH fractions together with a precipitate. TLC and HPLC analysis of the extracts and fractions, along with spectrophotometric determination of the total contents of flavonoids, tannins and proanthocyanidins indicated different chemical compositions for the preparations. Tannis showed the highest contents, reaching 75.0 ± 0.9% w/w in the n-BuOH fraction, whereas flavonoids and proanthocyanidins were the major compounds in the precipitate (5.80 ± 0.16% and 37.9% ± d.p. w/w, respectively). The potential vasodilator effect of the extracts and fractions were assayed in vitro using rat aortic rings pre-contracted with phenylefrine. All preparations were active and the vasodilatation elicited by some fractions (n-BuOH and aqueous soluble in MeOH), the precipitate and EB were statistically equivalents (pCI50 4.98 ± 0.06 to 4.85 ± 0.11; p 0.05). The contents of the assayed compounds and the of the biological assay were submitted to Spearman correlation analysis. Strong positive correlations were obtained between the vasodilator effect and the total contents of flavonoids (r = 0.90), proanthocyanidins (r = 0.90) and tannins (r = 0.60). Therefore, such groups of metabolites may constitute potential chemical markers for the species. The administration of EB and n-BuOH fraction to normotense mice (per os; doses of 10 and 100 mg/kg) induced hypotension, with significant differences among the doses (p < 0.05). The phytochemical study of C. carthagenensis afforded quercetin-3-sulfate and two flavonoids described for the first time for the species, quercetin-5-O--glucopyranoside and quercetin-3-O--arabinofuranoside. The above mentioned flavonoids are the major peaks found in the HPLC profiles of C. carthagenensis registered by DAD detector at 350 nm. An HPLC method was developed and partially validated to quantify the isolated flavonoids in the extracts of C. carthagenensis. The HPLC conditions for the simultaneous analysis of quercetin, gallic and ellagic acid in hydrolyzed extracts of C. carthagenensis was also established. However, the hydrolysis reaction did not present satisfactory precision for quantitative analysis. The isolated flavonoids as well total flavonoids, tannins and proanthocyanidins are potential chemical markers for Cuphea carthagenensis aerial parts | |
