Screening of Malaysian indigenous microalgae for antioxidant properties and nutritional value

Abstract

Fourteen indigenous microalgal samples from Malaysia were isolated, purified and cultured from fresh, brackish and marine waters. The ability of the microalgae to be natural sources of antioxidants was studied by a screening test using three antioxidant chemical assays [ferric thiocyanate (FTC), thiobarbituric acid (TBA) and 1, 1'-diphenyl-2-picrylhydrazyl (DPPH)]. The results showed that six microalgal methanolic crude extracts (Isochrysis galbana, Chaetoceros calcitrans, Scenedesmus quadricauda, Chlorella vulgaris, Nannochloropsis oculata and Tetraselmis tetrathele) were active in inhibiting the lipid peroxidation of linoleic acid. Among all the microalgae, I. galbana and C. calcitrans showed the highest antioxidant activity (>90%) in FTC and TBA assays, indicating that these microalgae might contain active compounds for protection from lipid peroxidation. Nutritional analyses were performed on microalgae with high antioxidant activities (I. galbana and C. calcitrans) in order to investigate their nutritive value. Both microalgae were found to be rich in nutrients. For examples, I. galbana had average percentage composition of protein, carbohydrate, and lipid, as 47.9±2.5; 26.8±0.2; 14.5±1.4%, respectively, while the corresponding values for C. calcitrans were 36.4±

Variations among Antioxidant Profiles in Lipid and Phenolic Extracts of Microalgae from Different Growth Medium

“…A significant scavenging activity of phenolic extract from both microalgae against super oxide radical was observed in the study which suggests the lipid peroxidation inhibition activity of Chlorella and Acutodesmus. Inhibition of lipid peroxidation by other microalgae was reported earlier (Natrah et al, 2007). An interesting finding of the study was potential free radical scavenging activity was found in phenolic extracts but total antioxidant potential values were doubled in lipid extracts of both microalgae grown in sewage water.…”

Microalgae for biodiesel production and other applications: A review

“…For example, nitrogen deficiency and salt stress induced the accumulation of C18:1 in all treated species and to some extent C20:5 in B. braunii [66]. Other authors also reported a differentiation between fatty acid composition of various algae species [19,23,47,59,62,69].…”

Relationship Between Total Phenolics Content and Antioxidant Activities of Microalgae Under Autotrophic, Heterotrophic and Mixotrophic Growth

“…Microalgae are being investigated for properties beneficial to the nutraceuticals and health foods industries and are promising alternative source of antioxidants (Li et al, 2007;Natrah et al, 2007;Rodriguez-Garcia and Guil-Guerrero, 2008;Chacon-Lee and Gonzalez-Marino, 2010;Lee et al, 2010). Microalgae exhibit adaptative responses to oxidative and radical stresses by producing potential chemicals via stimulation of their antioxidant defence system (Srivastava et al, 2005;Tsao and Deng, 2004).…”