Atividade antioxidante de Piper arboreum, Piper dilatatum e Piper divaricatum

Abstract

RESUMO: Os óleos essenciais de P. arboreum, P. dilatatum e P. divaricatum foram obtidos por hidrodestilação e analisados por CG-DIC e CG-EM. Extratos etanólicos foram preparados por extração exaustiva. A atividade antioxidante de óleos e extratos foi avaliada por meio do método de sequestro de radicais livres usando 2,2-difenil-1-picril-hidrazila. Os teores de óleos essenciais foram de 0,98%, 1,50% e 0,99% para P. arboreum, P. dilatatum e P. divaricatum, respectivamente. Esses óleos demonstraram riqueza em sesquiterpenos, sendo os principais componentes: biciclogermacreno (28,7%) e β-copaen-4-α-ol (13,3%) para P. arboreum; germacreno D (16,7%), α-alaskeno (18,9%) e viridiflorol (12,5%) para P. dilatatum; e germacreno D (9,4%), valenceno (11,1%) e g-cadineno (11,0%) para P. divaricatum. The essential oils of P. arboreum, P. dilatatum and P. divaricatum were obtained by means of hydrodistillation and analyzed by GC-FID and GC-MS. The ethanolic extracts were prepared by exhaustive extraction. The antioxidant activity of the oils and extracts were evaluated by applying the free radical scavenging method using the 2,2-diphenyl-1-picrylhydrazyl radical. The yields of the essential oils were 0.98%, 1.50% and 0.99% for P. arboreum, P. dilatatum and P. divaricatum, respectively. The oils are rich in sesquiterpenes, and the main components of P. arboreum are the bicyclogermacrene (28.7%) and β-copaen-4-α-ol (13.3%); of P. dilatatum, the germacrene D (16.7%), α-alaskene (18.9%) and viridiflorol (12.5%); and of P. divaricatum, the germacrene D (9.4%), valencene (11.1%) and g-cadinene (11.0%). The antioxidant activity test, based on the percentages of radical scavenging, determined the effective concentrations (CE 50 ) and the Antioxidant Activity Index (AAI). The following CE 50 and AAI values were found: 226.84 µg.mL -1 and 5.30 for ascorbic acid (used as the reference), 239.60 µg.mL -1 and 4.90 for P. arboreum, and 367.70 µg.mL -1 and 3.20 for P. dilatatum. The antioxidant evaluation using this methodology is not applicable for the P. divaricatum extract. These essential oils did not present a significant antioxidant activity. However, the ethanolic extracts of P. arboreum and P. dilatatum did show a strong antioxidant activity.

Gas chromatography coupled to mass spectrometry (GC-MS) characterization and evaluation of antibacterial bioactivities of the essential oils from Piper arboreum Aubl., Piper aduncum L. e Piper gaudichaudianum Kunth

“…The component identified in this study in the highest concentration of P. arboreum essential oil, β-copaen-4-α-ol (31.38%) diverges with that found by Silva et al [30], which identified bicyclogermacrene (28.7%) as the major component, in this same study β-copaen-4-α-ol was also identified, being characterized as the second component with the highest concentration.…”