Abstract
The endophytic fungus
was isolated from the brown alga
, collected from the Red Sea. The fungus was identified by its morphology and 18S rDNA. Cultivation of this fungal strain in biomalt-peptone medium led to isolation of 12 known metabolites of diketopeprazines and anthraquinones. The organic extract and isolated compounds were screened for their inhibition of hepatitis C virus NS3/4A protease (HCV PR). As a result, the fungal metabolites showed inhibition of HCV protease (IC
from 19 to 77 μM), and the fungus was subjected to culture on Czapek's (Cz) media, with a yield of nine metabolites with potent HCV protease inhibition ranging from IC
10 to 37 μM. The Cz culture extract exhibited high-level inhibition of HCV protease (IC
27.6 μg/mL) compared to the biomalt culture extract (IC
56 μg/mL), and the most potent HCV PR isolated compound (Griseoxanthone C, IC
19.8 μM) from the bio-malt culture extract showed less of an inhibitory effect compared to isolated ω-hydroxyemodin (IC
10.7 μM) from the optimized Cz culture extract. Both HCV PR active inhibitors ω-hydroxyemodin and griseoxanthone C were considered as the lowest selective safe constituents against Trypsin inhibitory effect with IC
48.5 and 51.3 μM, respectively.