Chemical evaluation and antioxidant capacity of polypehenolic extracts from bark of Pinus cooperi, P. engelmannii, P. leiophylla and 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 radical (ABTS•+), deoxyribose assay (scavenging of hydroxyl radical) and human Low Density Lipoprotein (LDL) inhibition 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^-1 to 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^-1 to 151 mg g^-1). The radical scavenging activity ABTS was (49,48% to 57,44%), similar to catechin standard (57,92%). The scavenging capacity of OH radical (25,85% to 48,46%), was higher in organic extracts for all species. 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.