Ultrasonic-assisted extraction and antioxidant capacities of flavonoids from Camellia fascicularis leaves

Ultrasonic-assisted extraction of flavonoids from Camellia fascicularis leaves was optimized using response surface methodology. The optimal extracting conditions of flavonoids were determined to be the ratio of liquid to raw material of 60mL/g, ethanol concentration of 40%, extraction temperature of 72.3 degrees C, and extraction time of 1.6h, which contributed to the highest flavonoids yield of 4.765%. The crude flavonoids were purified through an AB-8 macroporous adsorption resin column, eluted with ethanol concentration of 40%, and purified flavonoids were obtained. In vitro antioxidant assay demonstrated that purified flavonoids showed significant antioxidant capacities in a concentration-dependent manner for scavenging hydroxyl radical, superoxide anion radical, 2,2-diphenyl-1-picrylhydrazyl radical, and azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical. Overall, ultrasonic-assisted extraction was found to be an effective method of extracting flavonoids from C. fascicularis leaves, which might be explored as potential natural antioxidant. RESUMENMediante el uso de la metodologia de superficies de respuesta (msr) se optimizo la extraccion de flavonoides obtenidos de hojas de Camellia fascicularis asistida por ultrasonido. Al respecto, se establecio que las condiciones optimas para la extraccion de flavonoides son: ratio de liquido a materia prima de 60 mL/g, concentracion de etanol de 40%, temperatura de extraccion de 72,3 degrees C y tiempo de extraccion de 1,6 horas; a partir de estas condiciones se determino que el maximo rendimiento de los flavonoides es 4,765%. Empleando una columna de resina de adsorcion macroporosa AB-8 se purificaron los flavonoides crudos, siendo posteriormente eluidos con etanol en una concentracion de 40%. El ensayo mediante antioxidante in vitro demostro que, dependiendo de su concentracion, los flavonoides purificados tienen capacidades antioxidantes significativas para eliminar radicales de hidroxilo, anion superoxido, DPPH y ABTS. En general, se constato que la extraccion asistida por ultrasonido constituye un metodo eficaz para la extraccion de flavonoides de hojas de C. fascicularis, los cuales pueden ser sometidos a investigacion como un potente antioxidante natural.