Actividad antioxidante in vitro y toxicidad frente a Artemia salina de extractos hidroalcohólicos de cinco especies de cítricos
Fecha
2011-07-05
Autores
Herrera Sánchez, Yamila
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Editor
Universidad Central ´´Marta Abreu´´ de Las Villas
Resumen
Los cítricos constituyen un género de plantas rico en contenido de flavonoides,
metabolitos secundarios que debido a su efecto antioxidante y baja toxicidad,
han recibido en los últimos años mucha atención como potenciales fármacos.
En este trabajo nos propusimos determinar la actividad antioxidante in vitro y la
toxicidad frente a Artemia salina de extractos hidroalcohólicos de hojas de
cinco especies de cítricos (Citrus x aurantium var. sinensis L. Osbeck; Citrus x
aurantium L.; Citrusx aurantiifolia Christm. Swingle var. Mexicana; Citrus x
latifolia Tan. y Citrus reticulata Blanco.). Los extractos etanólicos y metanólicos
de hojas de estas plantas se obtuvieron mediante extracción asistida por
ultrasonido. Los fenoles y flavonoides fueron identificados empleando métodos
fitoquímicos y cromatografía en placa delgada, y la concentración total de los
mismos se determinó mediante el método Folin-Cioalteau-NaCO3 y NaNO2-
AlCl3, empleando ácido gálico y quercetina como patrón, respectivamente. La
actividad antioxidante de los extractos se determinó mediante la capacidad
atrapadora de radicales libre, el poder reductor, y la capacidad antioxidante
total, usando ácido ascórbico y quercetina como patrón. La toxicidad de los
extractos se evaluó mediante el ensayo de letalidad con A. salina. En los
extractos etanólicos se encontró mayor presencia relativa de las compuestos
químicas que en los extractos metanólicos. Los extractos de Citrus x latifolia
Tan. y Citrus reticulata Blanco. en metanol 70 %, fueron los extractos que
menos clases de flavonoides mostraron, mientras que el Citrus x aurantiifolia
Christm. Swingle var. Mexicana en etanol 70% fue el que presentó la mayor
variedad de clases de flavonoides. La mayor concentración de fenoles totales
se obtuvo en Citrus reticulata Blanco. en metanol 70% (38.47 mg de ácido
gálico/ mL de extracto) y de flavonoides totales se obtuvo en el extracto
etanólico de Citrusx aurantiifolia Christm. Swingle var. Mexicana (8.54 mg de
quercetina/ mL de extracto) y la mandarina en ambos solventes, etanol 70%
(8.31 mg de quercetina/ mL de extracto) y metanol 70% (6.89 mg de
quercetina/ mL de extracto). Todos los extractos mostraron actividad
antioxidante mediante las tres pruebas ensayadas. Los extractos presentaron
toxicidad moderada hacia A. salina, siendo en el extracto de Citrus x latifolia
Tan. en metanol 70% el que mostró menor toxicidad (LC 50 = 464.24 μg/ mL).
Citruses constitute an important source of flavonoids, secondary metabolites which have been recently studied extensively since they are highly effective antioxidant agents with a low toxic effect. They have received in the last years much attention like potential drugs. The aim of our work was to determine the antioxidant activity and toxicity against Artemia saline of leaf alcoholic extracts from five species of citruses (Citrus x aurantium var. sinensis L. Osbeck; Citrus x aurantium L.; Citrusx aurantiifolia Christm. Swingle var. Mexicana; Citrus x latifolia Tan. and Citrus reticulata Blanco. The ethanolic and methanolic leaf extracts from these plants were obtained by an ultrasound assisted extraction method. Phenols and flavonoids were identified using phytochemistry and Thin Layer Chromatography methods. Total phenols and flavonoids content was determined by Folin-Cioalteau-NaCO3 and NaNO2-AlCl3 methods by using galic acid and quercetin as standard compounds, respectively. The antioxidant activity was determined taking into account the free radical scavenging, the reducing power, and total antioxidant activity of the extracts by using ascorbic acid and quercetin as standard compounds. The toxicity was evaluated by the lethality test against A. saline. The major relative presence of the chemical compounds was obtained in ethanolic that in the metanolic extracts. Lima and mandarin extracts in methanol 70% showed fewer classes of flavonoids, whereas the lemon extract in ethanol 70% presented the greater variety of flavonoids classes. The greater total phenols concentration was obtained in mandarin extracts in methanol 70% (38.47 mg galic acid/ ml of extract) and from total flavonoids was obtained in the lemon ethanolic extract (8.54 mg of quercetin/ ml of extract) and mandarin extract in both solvents, ethanol 70% (8.31 mg of quercetin/ mL of extract) and methanol 70% (6.89 mg of quercetin/ mL of extract). All the extracts showed to antioxidant activity by the three tests. All plant extracts presented moderate toxicity against A. saline, being the Lima methanol 70% extract the one that showed the minor toxicity (LC 50 = 464.24 μg/ mL).
Citruses constitute an important source of flavonoids, secondary metabolites which have been recently studied extensively since they are highly effective antioxidant agents with a low toxic effect. They have received in the last years much attention like potential drugs. The aim of our work was to determine the antioxidant activity and toxicity against Artemia saline of leaf alcoholic extracts from five species of citruses (Citrus x aurantium var. sinensis L. Osbeck; Citrus x aurantium L.; Citrusx aurantiifolia Christm. Swingle var. Mexicana; Citrus x latifolia Tan. and Citrus reticulata Blanco. The ethanolic and methanolic leaf extracts from these plants were obtained by an ultrasound assisted extraction method. Phenols and flavonoids were identified using phytochemistry and Thin Layer Chromatography methods. Total phenols and flavonoids content was determined by Folin-Cioalteau-NaCO3 and NaNO2-AlCl3 methods by using galic acid and quercetin as standard compounds, respectively. The antioxidant activity was determined taking into account the free radical scavenging, the reducing power, and total antioxidant activity of the extracts by using ascorbic acid and quercetin as standard compounds. The toxicity was evaluated by the lethality test against A. saline. The major relative presence of the chemical compounds was obtained in ethanolic that in the metanolic extracts. Lima and mandarin extracts in methanol 70% showed fewer classes of flavonoids, whereas the lemon extract in ethanol 70% presented the greater variety of flavonoids classes. The greater total phenols concentration was obtained in mandarin extracts in methanol 70% (38.47 mg galic acid/ ml of extract) and from total flavonoids was obtained in the lemon ethanolic extract (8.54 mg of quercetin/ ml of extract) and mandarin extract in both solvents, ethanol 70% (8.31 mg of quercetin/ mL of extract) and methanol 70% (6.89 mg of quercetin/ mL of extract). All the extracts showed to antioxidant activity by the three tests. All plant extracts presented moderate toxicity against A. saline, being the Lima methanol 70% extract the one that showed the minor toxicity (LC 50 = 464.24 μg/ mL).
Descripción
Palabras clave
Citrus, Artemia Salina, Antioxidantes