Antioxidant potentialities of some strains belonging to endophytic, entomopathogenic and saprophytic fungi

Antioxidants have recently become the topic of interest as radical scavengers, which inhibit the free radical mediated processes. This study was carried out to investigate the antioxidant activity of 100 fungal strains (26 endophytes, 42 entomopathogens and 32 saprophytes). Three different assays (reducing power, total phenolic contents and flavonoid contents) were determined and used to evaluate the antioxidant potential of the fungal ethanolic extracts. The results revealed that all fungal strains under study showed antioxidant activity up to varying extent. A total of 21, 35 and 19 out of the tested endophytic, entomopathogenic and saprophytic strains, respectively, had a reducing power activity. High reducing power activities (≥ 0.6 mg/ml) were recorded by 9, 20 and 14 strains of the three tested groups, respectively. All tested strains have the ability to produce phenolic compounds with levels ranged from 0.92 to 63.44 mg/ml. The highest levels of total phenolic contents (≥ 40 mg/ml) observed in the extract of 12, 28 and 18 strains of endophytes, entomopathogens and saprophytes, respectively. Finally, all tested strains produced flavonoids with levels of 0.166 to 68.806 mg/ml. The highest flavonoid producers (formed ≥ 35 mg/ml) were only one strain of each of the endophytic and entomopathogenic fungi and three strains of saprophytic fungal group. The obtained results suggest that the tested strains, especially those of endophytes, had the potentiality as sources of strong natural and safe antioxidants for application in food and cosmetics industries