An endophytic Penicillium oxalicum isolated from Citrus limon possesses antioxidant and genoprotective potential

This study aimed at isolating endophytic fungi from Citrus limon (L.) possessing antioxidative and genoprotective potential.

Endophytic fungi were screened for antioxidant activity using 2,2-diphenyl,1-picryl hydrazyl radical scavenging assay and maximum activity (79·70%) was exhibited by culture MP1 identified to be Penicillium oxalicum on the basis of morphological and molecular characteristics. The ethyl acetate extract of MP1 was subjected to silica column chromatography followed by LH 20 column chromatography for purification of active metabolites. The partially purified active fraction of P. oxalicum MP1 possessed good antioxidant activity as detected using various assays. It also exhibited a strong DNA damage protection potential on pUC19 plasmid DNA treated with Fenton reagent. On exposure to active fraction of MP1 significant reduction (P < 0·05) in nuclear deformities (like nuclear buds, micronuclei, nuclear ridges and binucleated cells) was observed in human lymphocytes pretreated with a toxic concentration of H₂ O₂ . In vivo genoprotectivity studies were conducted in fresh water fish Channa punctatus pretreated with a damaging compound 4-nonyl phenol. The active fraction of P. oxalicum MP1 caused a reduction of 94·7 and 66·60% in micronuclei and aberrant cell formation, respectively. A significant reduction (P < 0·05) in tail length and tail DNA parameters was also observed in comet assay.

The endophytic P. oxalicum isolated in this study has the potential to produce metabolites possessing antioxidant and genoprotective activities.

The isolated culture can be exploited in the field of therapeutics by virtue of its in vitro and in vivo genoprotective potential.