Contribución al estudio fitoquímico de las hojas de la especie Cavendishia bracteata (Ericaceae) y evaluación de su capacidad antioxidante

Abstract

The present investigation describes the results obtained from the chemical and biological study carried out on the ethanolic extract and the respective fractionations of the leaves of the species Cavendishia bracteata, from the ethanolic extract (E.EtOH.CbH 101.104 g, 25.348%) the analysis was performed preliminary phytochemical (AFP) in which the presence of steroids, triterpenoids, sesquiterpenlactones, tannins, saponins and coumarins was qualitatively established; after that, a continuous liquid-liquid fractionation was carried out with solvents of increasing polarity, obtaining the fractions of heptane (F. Hept.CbH 0.05 g, 0.14%), dichloromethane (F.DCM.CbH 0.88 g 2.28% ), ethyl acetate (F. AcOEt.CbH 10.36 g 26.767%) and a hydroalcoholic residue (F. Hydroalc.CbH 27.54 g 70.808%). The separation of the extracts and fractions by column chromatography (CC), thin layer (CCD) and preparative (CCDP), allowed the isolation of a diterpene derived from sarandacopimaric acid (Sandaracopimar-15-en-8ß-il acetate) and two flavonoids; 3,5,7,3 ’, 4’ pentahydroxyfllavone (Quercetin) and 3-O-galactopiranoside from Quercetin (Hyperoside). In addition to obtaining a mixture consisting of a norisoprenoid (dihydroactinidiolide), a derivative of fumaric acid (1-ethyl 4- (2 methylprop-2-en-1-yl)), a sesquiterpene (3-oxo-α-ionol ) and a derivative of linoleic acid (methyl octadeca-8,11-dienoate). From 1000 g of fresh leaves of C. bracteata, the essential oil was obtained by the steam entrainment distillation technique obtaining a yield of 0.1%, analyzed by determined GC-MS so that lactone (5, 6-dihydro-2H-pyran-2-one) has the highest percentage of relative composition within the oil with 84.23%. Finally, the antioxidant capacity was determined by the free radical uptake method 2,2-diphenyl-1-picrylhydracil (DPPH), where the extract (E.EtOH.CbH) presented an IC50 of 439.85 ppm, and the F fractions. DCM.CbH, F.AcOEt.CbH and F.hydroalc.CbH an IC50 of 528.39, 326.68 and 548.77 ppm respectively; Taking the trolox positive control as a reference standard, it was established that the extract and the fractions have an acceptable antioxidant capacity, with the ethyl acetate fraction being the most effective.