SCREENING OF THE ANTIOXIDANT ACTIVITY OF CRUDE EXTRACTS IN 86 ALGAE SPECIES FROM EL JADIDA COAST (MOROCCO)

Objective: This work aimed to screen the antioxidant activity of marine macroalgae from the Moroccan Atlantic coast (region of El Jadida). Methods: Evaluation of the antioxidant activity of different collected species, lyophilized and extracted with a solvent mixture chloroform/methanol (2/1; v/v) was conducted according to two techniques, first by thin layer chromatography (tlc) then by spectrophotometry, using a free radical 2,2-diphenyl-1-picrylhydrazyl (dpph). The sampling on a distance of 110 km allowed to harvest 86 algal species (16 brown algae, 47 red algae, 14 green algae and 9 algae being identified). Results: The analysis by thin layer chromatography reveals an antioxidant activity in nearly half of harvested algal species (52.32 %). This activity varies depending on the concentration of the extract and in function of incubation time in the presence of dpph. The monitoring of the kinetics of degradation of dpph by spectrophotometer in the presence of extracts which were active by tlc allowed to confirm the results and select the most active algal species based on the percentage of remaining dpph in the medium after 120 min of reaction: Fucus spiralis (17.02 %), Cyctoseira ericoides (12.16 %) (Phaeophyceae), and Gracilaria multipartita (36%), Halopitys incurvus (5%) (Rhodophyceae). Conclusion: The results show that the methodology adopted in this work is reliable and can be used for rapid screening of antioxidant property in plants and the species: Fucus spiralis, Cyctoseira ericoides, Gracilaria multipartita, and Halopitys incurvus can be a promising source of natural compounds endowed with high antioxidant potential.