Evaluation of antioxidant potential of crude extract of metabolites from endophytic fungi isolated from Annona senegalensis Pers

Abstract

Degenerative diseases resulting from free radicals can be prevented through the use of natural antioxidants. This study aimed to assess the free radical scavenging potential of the underexplored endophytic fungal metabolites from Annona senegalensis Pers (wild custard apple). Freshly collected root, midrib, and leaf tissues were planted on malt extract agar following surface sterilization with 70% ethanol for 3 minutes, washed twice with distilled water, immersed in a sodium hypochlorite solution (4%) for 5 minutes, and subsequently rinsed with sterile water. Seven endophytic fungi were isolated, and the antioxidant activity of their metabolites was evaluated using the 2,2- diphenyl-1-picrylhydrazyl free radical scavenging method, with ascorbic acid serving as a reference antioxidant. The crude extract from the seven endophytic fungal isolates demonstrated concentration- dependent antioxidant activities. LB2 exhibited a strong antioxidant activity with an IC50 value of 38.15 μg/ml. Extracts from RT1 and LB1 showed antioxidant activities, with the highest inhibition of 60% and 65%, respectively, observed at a concentration of 1000 μg/ml. This was compared favorably to ascorbic acid, which exhibited 94% inhibition. This indicates that the crude extract from endophytic fungi isolated from A. senegalensis possesses free radical scavenging properties. Further purification and elucidation of the crude extract will reveal the bioactive compounds responsible for the antioxidant activities.