Bio-Therapeutic, Phytochemical Screening and Antioxidant Efficacies of Oyster Mushroom (<i>Pleurotus ostreatus</i>) Obtained from the Wild

Abstract

Pleurotus ostreatus was obtained from the wild and evaluated for its antibacterial and antioxidant activities. The antibacterial activities of the methanolic and aqueous extracts against clinical isolates of Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli with vancomycine and amicosin as positive control against the isolates were examined using agar well diffusion assay and the zones of inhibition for the methanolic extract varied for different organisms as zones of inhibition were highly pronounced in Escherichia coli having 18.0 ± 1.41 mm followed by Klebsiella pneumoniae of 17.0 ± 0.58 mm then Staphylococcus aureus of 14.0 ± 1.53 mm and finally Pseudomonas aeruginosa 13.0 ± 0.58 mm. While for the aqueous extract, no inhibition was observed in three isolates apart from Pseudomonas aeruginosa in which the zone of inhibition was just 8.0 ± 1.00 mm. The total antioxidant activity of aqueous Pleurotus ostreatus differed significantly with total phenolic of 12.55 ± 0.11 mg GAE/g, total flavonoid of 7.22 ± 1.60 mg QE/g, ABTS of 1.99 ± 0.06 mmol TEAC/100g, FRAP of mean value of 5.25 ± 0.25 mg/g and also Pleurotus ostreatus was able to scavenged DPPH in a dose-dependent manner of 0 - 13.3 mg/ml. The inhibitory effect of Pleurotus ostreatus can therefore be attributed to the presence of phenolic and flavonoid compounds in the extract. Also, the result of the ABTS+ scavenging ability of Pleurotus ostreatus as trolox equivalent antioxidant capacity (TEAC) revealed that the extracts of Pleurotus ostreatus has ABTS scavenging ability. The FRAP mean value shows the ability of Pleurotus ostreatus extract to reduced Iron (III) to Iron (II) indicates its redox potential which presents the mushroom a good antioxidant source, suitable for health benefits when consumed.