Extraction of Polyphenols from Porphyra and Scavenging Activity of Oxygen Free Radicals

Abstract

Polyphenols from Porphyra are important biological active substances. The effects of temperature, times, ethanol concentration and liquid to solid ratio were studied for the extraction yield of polyphenols from Porphyra through a single-factor exploration.Then, through an orthogonal experiment, it was investigated to get the best extraction conditions. The content of polyphenols was determined by Folin-Ciocalteu method. Scavenging ability to oxygen free radicals was also assessed. The results show that extraction temperature is 75°C, the extraction time is 2.5 h, ethanol concentration is 70% and the ratio of liquid to solid is 25:1(mL/g).The proportion of the extraction of the polyphenols from Porphyra under these industrial process conditions is 6.263mg/g. Polyphenols from Porphyra have strong scavenging hydroxyl radical and superoxide anion radical. IC50 of polyphenols from Porphyra on hydroxyl radical and superoxide anion radical is 0.405 mg/mL, 0.539mg/mL, respectively.