Antioxidant activity and phenolic compounds of the extract from pigment-producing fungi isolated from Brazilian caves

Abstract

Few studies have been carried out on the biotechnological potential of microorganisms growing inside caves. Fungi are found in several environments and are sources of metabolites that present biological activities and can be used for industrial purpose. The objective of this study was to evaluate the antioxidant activity and phenolic compounds of extract from pigment-producing fungi isolated from Brazilian caves. The antioxidant activity was evaluated using the free radical scavenging methods 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS•+) assays and the β-carotene-linoleic acid system, while the content of total phenolic compounds was measured using the Folin-Ciocalteu method. Eight fungal isolates were selected based on their pigment production in solid culture media. The ethyl acetate extract of the Penicillium flavigenum CML2965 was highlighted among the analyzed extracts, exhibiting 98.2%, 47.1%, and 72.2% of antioxidant activity according to the DPPH and ABTS•+ methods and β-carotene system assay, respectively. In addition, the total phenolic compound content in the extract was 201 mg gallic acid equivalent (GAE)/g. The phenolic compounds gallic acid, catechin, chlorogenic acid, caffeic acid, and vanillin were identified and quantified using high-performance liquid chromatography with diode array detection. The high concentration of phenolic compounds, especially gallic acid (11.9 g/L), contributed to the antioxidant activity observed in the extract of P. flavigenum (CML2965). Therefore, this fungus shows biotechnological potential for the synthesis of gallic acid, which has several applications in the food and pharmaceutical industries.