Abstract The current study estimated the antioxidant activity and biochemical composition of four seaweeds; Toania atomaria (Phaeophyta), Padina pavonia (Phaeophyta), Jania rubens (Rhodophyta) and Corallina elongate (Rhodophyta). The highest total antioxidant activity was observed with ethanol extract of T. atomaria (44.6 ± 1.6 mg ascorbic acid equivalents/g crude extract). Among the four seaweeds, ethanol extract of T. atomaria has recorded the highest value in ferric reducing antioxidant power (FRAP) assay (32.3 ± 0.0 mg ascorbic acid equivalents/g crude extract). The uppermost level of carbohydrates was (20.4% ± 0.4 and 19.5% ± 0.7 dry wt.) in P. pavonia and T. atomaria. Proteins were maximum (10.5% ± 0.6 and 8.0% ± 0.0 dry wt.) in P. pavonia and T. atomaria. The results detected that T. atomaria had the largest amounts of lipids (5.92% ± 0.09 dry wt.). The polyunsaturated ω6 essential fatty acids were recorded in T.atomaria, P. pavonia, and J. rubens (11.39%, 8.09%, and 6.28%), and ω3 essential fatty acids were recorded in T. atomaria and P. pavonia (0.65% and 0.97%). The seaweeds are interesting candidates for medicinal, pharmaceutical, and nutritional applications owing to their antioxidant activities, biochemical composition; they are not widespread in the coastal waters of Egypt and has few studies, especially T. atomaria.

In the present study, the effects of Spirulina on subchronic treatments (two weeks) of hyperlipidemia and liver function of the rats and humans were investigated. The hyperlipidemia was induced in the rats using 25% of soya bean oil and 25% butter. The butter induced more hyperlipidemia than soya bean oil. Spirulina was used at the concentrations of 0, 2.5, 5.0 and 10 % of diet weight of the rats. The decrease in hyperlipidemia by Spirulina was dependent on its concentration in the diet. In case of human studies, about four g/day of Spirulina was taken via oral administration by Egyptian volunteers patients with hyperlipidemia. Spirulina decreased the levels of hyperlipidemia in these patients. The effects were dependent on the amount and number of administered dose of Sprirulina. The results suggested that the Spirulina treatment could induce marked reduction of aminotransferase through correcting lipid profile and increasing high density lipoprotein.

The effect of industrial wastewater on the Nile cyanobacteria Pseudanabaena limnetica and Anabaena wisconsinense was investigated. The data showed that P. limnetica was more sensitive to pollution than A. wisconsinense. The treatments with different levels of wastewater exerted pronounced reductions in protein and amino acids content. SDS-PAGE analysis revealed that the cyanobacteria grown in the industrial wastewater showed induction in the synthesis of certain polypeptides and repression of others. The treatments of P. limnetica with wastewater stimulated the appearance of six protein bands with molecular masses of 28, 30, 31, 32, 58 and 97 kDa. The same treatments caused the disappearance of 20, 38 and 56 kDa. The structural protein pattern of the treated A. wisconsinense showed appearance of 16, 30, 170 and 230 kDa and disappearance of 56 kDa. The treatment of the two investigated cyanobacteria with different levels of wastewater stimulated the biosyntheses of different amino acids and inhibited others.