ABSTRACT
An exopolysaccharide Exopolysaccharide (EPSNC2) produced from marine Streptomyces hirsutus NRC2018 whichwas isolated from marine sediments at North Coast, Egypt with accession number MK050544. EPSNC2 was a β-typeheteropolysaccharide contained uronic acid (72.73%) with no sulfate groups and overall average molecular weight(Mw) 4.25×105 g/mol. The monosaccharide composition was glucuronic:galacturonic:glucose:mannose:arabinosewith molar ratio 1.2:0.6:0.1:0.2:0.1, respectively. EPSNC2 was subjected to antioxidant, anticancer, and antiviralin vitro tests, showed high 1, 1-diphenyl-2-picrylhydrazyl free radical scavenging activity whereas, the maximumantioxidant activity was 95.9% at 1,500 µg/ml after 120 minutes and the IC50 value was 158.5 µg/ml. Also, EPSNC2had the ability to scavenge H2O2 and the maximum activity was 75.6% with an estimated IC50 value 501.2 µg/ml.Furthermore, EPSNC2 showed a reducing power activity as well as a metal chelating activity in a dose dependantmanner and the activity reached 98.5% at 1,000 µg/ml. EPSNC2 had a significant and specific anticancer effect onCaCo-2 cell line without any effect on other cell lines and the IC50 was estimated to be 295.1 µg/ml. Our resultsregarding the antiviral activity against Herpes Simplex virus type 1 (HSV-1), Hepatitis A virus, and Coxsackie B-4were 84.9%, 20.3%, and 45.4%, respectively at 125 µg/ml with no activity against adenovirus. Therefore, the EC50value against the enveloped virus HSV-1 was 32.4 µg/ml.