A pilot study of antioxidant potential of endophytic fungi from some Sudanese medicinal plants

To evaluate the total phenolic content and total antioxidant capacity of ethyl acetate extracts of 21 endophytic fungi isolated from five Sudanese medicinal plants: Calotropis procera, Catharanthus roseus, Euphorbia prostrate, Vernonia amygdalina and Trigonella foenum-graecum.

Crude extracts of endophytic fungi and their host plants were tested by classical Folin-Ciocalteu colorimetric method to determine the total phenolic content, also total antioxidant capacity was estimated using 1,1-diphenyl-2-picrylhydrazyl free radical scavenging in vitro method.

Among the endophytes, endophytic fungus Aspergillus sp. from Trigonella foenum-graecum seeds demonstrated the highest both total phenolic content in term of gallic acid equivalent [(89.9 ± 7.1) mg GAE/g] and antioxidant activity for 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay [IC50: (18.0 ± 0.1) μg/mL]. A high positive linear correlation (R(2) = 0.999 1) was found between total antioxidant capacity and total phenolic content of endophytic fungi isolated from Vernonia amygdalina.

The present study revealed that some endophytic fungi from the five Sudanese medicinal plants could be a potential source of novel natural antioxidant compounds.