Sedigheh Hashemnia

Increased demand for food and protein results in an increased usage of microalgae as a potential source of natural biochemical compounds with active antioxidant properties. In this study, the green-blue algae Nostoc was cultivated successfully in Persian Gulf Research Instituate laboratory. In the first part of this study, optimum growth conditions were provided for the cultivation of the microalgae, then it was harvested by centrifugation. The resulted biomass was washed withdistilled water to remove soluble salts and then dried using freeze dryer at -50 ºC. To enhance the protein extraction, cell distruption was used by homogenization method. The total protein content was 0.16 mg/g of dry extract using lowry method. Total phenolics content of the protein extract (Folin-Ciocalteu colorimetric method) was determined to be 6.85 mg of gallic acid equivalent /g of dry extract. Total antioxidant capacity of protein extract (Prieto method) was determined to be 5.737 mg ascorbic acid equivalent/ g of dry extract. The differential pulse voltametric (DPV) technique was used to evaluate the DPPH (Di phenyl picryl hydrazyl) and ABTS (2,2-azino-bis (3-ethyl benzothiazoline-6-sulfonic acid)) radical scavenging ability. For this purpose, the gold nanoparticles were used for surface modification of carbon screen printed electrode and preparation of electrochemical sensors. To investigate the scavenging radical activity of protein extract, DPPH and ABTS were used as target compounds and IC50 were calculated 0.06 and 0.04 respectively. Also, the anticancer activity of the protein extract was evaluated MCF-7 and AGS cell lines using MTT assay. MTT assay confirmed the ability of extract to inhibit some certain cancer cells.