Microwave-Assisted Extraction and Antioxidant Activities of Polyphenols from Camellia Fascicularis Leaves

A microwave-assisted extraction method was established and optimized for extracting polyphenols from the leaves of Camellia fascicularis, which possess antioxidant properties. Microwave-assisted extraction of polyphenols from C. fascicularis leaves was optimized using response surface methodology. The influential factors, including ethanol concentration, ratio of liquid to raw material, and microwave power, were studied to optimize the extraction process, while setting the irradiation time to 20 s. The optimum process parameters, namely, ethanol concentration of 50%, the ratio of liquid to raw material of 32 mL/g, and microwave power of 160 W, contributed to the highest polyphenol yield of 106.1 mg GAE/g dw. The crude polyphenols were purified through an HP-20 macroporous adsorption resin column to obtain purified C. fascicularis polyphenols. Antioxidant assay demonstrated that purified polyphenols from C. fascicularis showed significant antioxidant activities in a concentration-dependent manner for scavenging hydroxyl, 2,2-diphenyl-1-picrylhydrazyl, and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radicals. Thus, microwave-assisted extraction was an effective method of extracting polyphenols from C. fascicularis leaves, which might be an excellent food material with potential antioxidant properties.