Extraction of antioxidant phenolic compounds from Algerian inula viscosa leaves: influence of the harvest period and optimization

Abstract

The aqueous extraction of polyphenols from Inula viscoa leaves was carried out on two different lots in order to study the influence of the picking period on the phenolic content and on the antioxidant characteristics of the extracts obtained, as well as on the optimization of technological parameters. For the two lots studied, the simple effect of temperature, the solid to liquid ratio and the interaction effect between temperature and solid to liquid ratio are the most influential parameters on all recorded responses. The phenological cycle of the plant affects the amount of phenolic compounds recovered, as well as the antiradical power and the antioxidant characteristics. The multi-response optimization of the extraction conditions gives polyphenol contents of 291 and 251 mg GAE. g-1 DW and antiradical activities of 90 and 89% for the purified extracts of July and December, respectively.