In vitro Antioxidant Activity of Marine Diatoms

The in vitro total antioxidant assay, total phenolic content, DPPH assay, FRAP assay of the acetone extracts from four centric diatoms (Chaetoceros simplex, Skeletonema costatum, Odontella mobiliensis, Coscinodiscus centralis) and three pennate diatoms (Nitzschia closterium, Pleurosigma angulatum and Navicula sp.) were performed. The centric diatom, O. mobiliensis was found higher amount of phenolic content (0.75 ± 0.06) followed by C. simplex. The maximum total antioxidant activity of 45.03 ± 2.1 ascorbic acid equivalent/g was observed in P. angulatum followed by the centric diatom C. simplex. The O. mobiliensis was showed significantly higher DPPH radical scavenging activity of 70.04 ± 4.17 % followed by C. simplex (55.69 ± 2.52 %) and P. angulatum (49.57 ± 2.74 %). The phenolic compounds of acetone extracts were not major contributor to the antioxidant capacities of these diatoms. The pigments such as, chlorophylls and carotenoids may be the main contributor of antioxidant activity in this study. The total antioxidant activity may be increased when extracted other solvent. Thus, these species can be act as natural antioxidant source for food preservation and protection of organisms from the degenerative diseases.