The objective of this work was to screen fungi isolated from soil of different areas of Punjab, India for
antioxidant activity by dot blot assay and around 45% of fungal isolates demonstrated antioxidant potential.
Two selected strains of Aspergillus spp (Aspergillus PR78 and Aspergillus PR66) showing quantitatively
best antioxidant activity by DPPH assay were further tested for their reducing power, ferrous ion and nitric
oxide ion scavenging activity, FRAP assay and total phenolic content. Different physio-chemical
parameters were optimized for enhancement of the activity. This revealed stationary culture grown for 10
days at 25 oC at pH 7 to be the best for antioxidant activity. Sucrose in the medium 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 among these. The extraction of the broth culture filtrates with
different solvents revealed ethyl acetate extract to possess the best antioxidant activity. The activity as
expressed by ethyl acetate extract of Aspergillus PR78 was equally effective as that of commonly used
antioxidant standard, ascorbic acid.
