Antioxidant activity of macroalgae from the Azores

Abstract

Free radical scavenging activity (FRSA) was studied to determine the antioxidant activity of 8 common macroalgae species found in the Azores. Species under study were Porphyra sp., Osmundea pinnatifida, Pterocladiella capillacea, Sphaerococcus coronopifolius and Gelidium microdon, from Rhodophyta; Ulva compressa and Chaetomorpha pachynema, from Chlorophyta and Fucus spiralis from Phaeophyta.The antioxidant activity was evaluated in methanolic extract by a decolourisation solution test of 2,2-diphenyl-1-picrylhydrazyl (DPPH), used as a stable radical. The methanolic extracts were obtained from dried biomass by sequential extractions, attaining a final concentration of 2 mg.mL-1. The FRSA values ranged from 19.54% for S. coronopifolius to 60.05% for F. spiralis with standard deviation (SD) varying between 1.41% and 6.80%. Results indicated that the studied seaweeds are a very promising source of biological active compounds with antioxidante properties. The seaweeds were collected in the Azorean islands where seawater pollution levels are low. Consequently, these seaweeds represent a valuable and good source of antioxidante material with superior beneficial effects on human health.