Optimization and Assay of Antioxidant Potential of Two Penicillium spp. by Different Procedures

The objective of this work was to evaluate the antioxidant potential of two strains of Penicillium spp. (Penicillium citrinum and Penicillium granulatum) isolated from soil, through different assay procedures (1,1-diphenyl-2-picryl hydrazyl (DPPH) assay, reducing power, ferrous ion and nitric oxide ion scavenging activity, ferric reducing antioxidant power (FRAP) assay). The total phenolic content was also estimated. Different physio-chemical parameters were optimized for enhancement of antioxidant activity. This revealed stationary culture grown for 10 days at 25 °C at pH 7 to be the best for antioxidant activity. Sucrose as carbon source resulted in highest antioxidant activity. Sodium nitrate, yeast extract, and peptone were good sources of nitrogen but sodium nitrate was the best. The extraction of broth culture filtrates with different solvents revealed ethyl acetate extract to possess the best antioxidant activity.