A Comparison of the Antioxidant Properties and Total Phenolic Content in a Diatom, Chaetoceros sp. and a Green Microalga, Nannochloropsis sp.

Abstract

The aquaculture industry commonly makes use of microalgae as live feed. Chaetoceros sp., a diatom, andNannochloropsis sp., a unicellular green microalga, have both been reported to contain a substantial amount ofpolyunsaturated fatty acids and carotenoids. Their potential as natural sources of antioxidants has gained recentattention. This study focuses on determining the antioxidant properties of the different solvent extracts, namelyhexane, dichloromethane, chloroform and methanol, from both microalgae. The evaluation of antioxidantcapacities was done by Folin-ciocalteu, 1,1-diphenyl-2-picrylhydrazyl radical-scavenging, metal chelating,nitro-blue tetrazolium reduction and ferric-reducing antioxidant power assay. Results showed that the non-polarsolvent extracts from the diatom were highest in antioxidant power, whereas both polar and non-polar solventextracts of green microalgae showed good antioxidant potential. In general, Chaetoceros sp. had higherantioxidant capacities than Nannochloropsis sp. This study suggests that different solvent extracts containdifferent potential antioxidant compounds able to scavenge different types of free radicals.