Evaluación química y capacidad antioxidante de extractos polifenólicos de cortezas de Pinus cooperi, P. engelmannii, P. leiophylla y P. teocote

total phenolics, flavonoids and proanthocyanidins from aqueous acetone 70% (crude extract) and semi purified extracts by liquid-liquid partition with ethyl acetate (organic fraction) of pinus cooperi, pinus engelmannii, pinus leiophylla and pinus teocote bark were evaluated. the antioxidant activity using acid 2,2'-azinobis-3-etilbenzotiazolin-6-sulfonic radlcal (abts.+), deoxyribose assay (scavenging of hydroxyl radical) and human low density lipoprotein (ldl) inhibitlin were also determined. chromatographic analysis of high pressure liquid chromatography (hplc) of extracts was performed. total phenolics concentration was 491 mg g-1 to 604 mg g-1, organic extracts showed higher flavonoids concentration (292 mg g-1 to 385 mg g-1) than crude ones (259 mg g-1to 314 mg g-1), while proanthocyanidins concentration was higher in crude extracts (186 mg g-1 to 286 mg g-1) than organic extracts (70 mg g-1to 151 mg g-1). the radical scavenging activity abts was (49,48% to 57,44%), similar to catechln standard (57,92%). the scavenging capacity of oh radlcal (25,85% to 48,46%), was higher in organic extracts for all specles. the ldl oxidation inhibition for organic extracts (64,41% to 89,39%), was higher than crude extracts. catechin was identified in all species at low concentration. hplc chromatograms showed a flavanone as the major compound in p. cooperi, p. engelmannii, and p teocote bark extracts.