An overview of antioxidant capacity, total phenolics, and amino acids of Aureobasidium pullulans GM6

Abstract

Aureobasidium pullulans grown in submerged flask culture for 5 days was investigated for antioxidant activity. The ethanolic extract of mycelium was used for determination of the antioxidant properties using different methods: total antioxidant activity, linoleic acid bleaching, DPPH free radical scavenging, hydrogen peroxide and hydroxyl radical scavenging activities, reduction of metal ions, and chelating abilities against ferrous ions. Total phenolics and amino acids content was establish in amount of 5.78 mg GAE and 5.16 µg Gly/g dry extract, respectively. The result of total antioxidant activity showed 7.83 µg AA/g dry extract. The results for free radical-scavenging activities in terms of DPPH, H2O2, and OH expressed as EC50 were 61.81, 26.61, and 69.79 µg/ml, respectively. The extract showed very potent reducing and chelating power (EC50 = 0.51 and 35.02 μg/ml, respectively). Total phenolics and amino acids contents of the extract were attributed to overall antioxidant capacity (r = 0.707–1.000) and (r = 0.140–0.978), respectively. Practical applications Aureobasidium pullulans is most famous fungus belonging to the family Dothioraceae. The fungus produces a broad range of natural products which have been regarded as safe and very important for nutraceutical, pharmaceutical, and environmental application. Among the best known products are: pullulan (exopolysaccharide), numerous commercially enzymes (protease, lipase, xylanase, amylase, pectinase, etc.), secondary metabolites, and antibiotics. Investigating isolates of the fungus that live in different extreme conditions and optimizing the experimental conditions for the production of natural products are of great importance for their practical application. The current study was focused on the details evaluation of antioxidant profile, content of total phenolics and amino acids in EtOH extract of mycelium A. pullulans GM6, after 5 days of incubation in submerged conditions. These data will provide some useful information relevant to understanding the antioxidant role of the fungus and further screening of isolate as potential source of new natural antioxidants.