Lipids composition and antioxidant properties of selected microalgae isolated from freshwater and soil samples

Abstract

Sourcing for natural antioxidants for nutraceutical and pharmaceutical industries is receiving global attention. In view of this, aqueous and methanolic extracts of Chlorococcus sp., Chlamydomonas sp. and Chlorella sp. isolated from Ogunpa river, Uren river and Oil palm plantation respectively were screened for their total phenolic, flavonoids and radical scavenging activity against the stable radical 1,1-diphenyl-2-picrylhydrazyl to establish their antioxidant potential. The culture samples using Bold’s Basal Medium were analysed for lipids contents and fatty acid analysis was carried out with a Gas Chromatography Mass Spectrometer system fitted with an HP-5MS (5% Helium) column. For lipid content, Chlorella sp. recorded twenty-two fatty acids with Undecanoic acid (methyl ester) as most abundant, as compared with Chlamydomonas sp. and Chlorococcus sp. Methanolic extracts of Chlorella sp. exhibited the highest antioxidant activity (63.24µg/100ml), probably due to high contents of total phenols (33.02µg/100ml) and flavonoids (14.35 µg/100ml) while methanolic extract of Chlorococcus sp. recorded higher radical scavenging activity. However, Chlamydomonas showed higher percentage radical inhibition (72.48%) at 100µg/ml.