Valproic Acid Enhances Antioxidant Potential of Setosphaeria rostrata, an Endophytic Fungus of Datura innoxia Mill.

The endophytic fungus Setosphaeria rostrata K.J. Leonard, 1976, was isolated from Datura innoxia Mill. and characterized by analysis of nucleotide sequences of the Internal Transcribed Spacer (ITS) region. To diversify the secondary metabolites in the fungus, valproic acid (a histone deacetylase inhibitor) was supplemented and subsequently evaluated for the antibacterial, total phenolic content and antioxidant activity. A significant difference in the antioxidant activity and phenolic content was observed among the extracts. The ethyl acetate extract obtained from the experimental part has shown almost two fold increase in the antioxidant activity. The total phenolic content was higher in ethyl acetate extract of the control than experimental sample. The control and experimental extracts were found to have mild activity against Pseudomonas aeruginosa (NCIM 5029). To support the difference in antioxidant activity, the extracts were analyzed via Gas Chromatography and Mass Spectroscopy (GCMS) and the profile of volatile metabolites was obtained. The outcome obtained from GCMS profile has supported the differences observed between the extracts. This study remarkably depicts that the valproic acid can be used to diversify the secondary metabolites in fungi.