Atividade antioxidante de Piper arboreum, Piper dilatatum e Piper divaricatum / Antioxidant activity of Piper arboreum, Piper dilatatum, and Piper divaricatum

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 ß-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 γ-cadineno (11,0%) para P. divaricatum. No teste de atividade antioxidante, com base nas percentagens de sequestro de radicais, foram determinados a concentrações efetivas (CE50) e o Índice de Atividade Antioxidante (IAA). Os seguintes valores de CE50 e IAA foram encontrados: ácido ascórbico (usado como referência) 226,84 µg.mL-1 e 5,30; extrato de P. arboreum 239,60 µg.mL-1 e 4,90, e extrato de P. dilatatum 367,70 µg.mL-1 e 3,20, respectivamente. A metodologia utilizada para a atividade antioxidante mostrou-se inadequada para o extrato da P. divaricatum. Os óleos essenciais não apresentaram atividade antioxidante significativa, entretanto, os extratos etanólicos de P. arboreum e de P. dilatatum apresentaram atividade antioxidante expressiva.

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 ß-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 γ-cadinene (11.0%). The antioxidant activity test, based on the percentages of radical scavenging, determined the effective concentrations (CE50) and the Antioxidant Activity Index (AAI). The following CE50 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

Suspensiones celulares y producción de metabolitos secundarios en cultivos in vitro de Piper sp / Cellular suspension and production of secondary metabolites in in vitro cultures of Piper sp

Piperaceae is an important family from neotropical American in which many biologically active compounds were identified. A survey of structural diversity and bioactivity reveals that groups of species specialize in the production of amides, phenylpropanoids, lignans and neolignans, benzoic acids and chromenes, alkaloids, polyketides, and a plethora of compounds of mixed biosynthetic origin. With this in mind, several explants obtained from in vitro plantlets were cultured in the presence of different plant growth regulator combinations (IAA, NAA, 2,4-D, DICAMBA, BAP and KIN). The callus induction was depended of Piper species, explant type and plant growth regulator combinations. From a callus culture, cell suspension cultures were established and their growth and metabolite accumulation studied. The achieve results may be useful for further characterization of the activated secondary metabolites pathways in in vitro systems of various Piper species.

Piperaceae es una familia importante de la América neotropical en la que muchos compuestos biológicamente activos han sido identificados. Un estudio general sobre la diversidad estructural y bioactividad reveló que grupos de especies se especializan en la producción de amidas, fenilpropanoides, lignanos y neolignanos, ácidos benzoicos y cromenes, alcaloides, policétidos y una diversidad de compuestos de origen biosintético mixto. Con este conocimiento, diversos explantes obtenidos de plántulas in vitro se cultivaron en presencia de diferentes combinaciones de reguladores de crecimiento (AIA, ANA, 2,4-D, DICAMBA, BAP y KIN). La inducción de callos dependió de la especie de Piper, tipo de explante y las combinaciones de los reguladores de crecimiento. Suspensiones celulares se establecieron a partir de callos y estudiadas en su crecimiento y acumulación de metabolitos. Los resultados alcanzados pueden utilizarse para caracterizar rutas de producción de metabolitos secundarios, en sistemas in vitro, en varias especies de Piper.