Nutritional composition, antioxidant activity, antibacterial activity, GC-MS based metabolite profile of Pleurotus giganteus (Berk.)

Aim: This study aimed to evaluate the nutritional composition, antioxidative and antibacterial properties of the wild myco-food Pleurotus giganteus. The study is relevant to nutritional and medicinal properties of P. giganteus and its perspective applications in functional food, nutraceutical and pharmaceutical industries. Methodology: P. giganteus was characterised morphological and molecularly. The nutritional properties and element contents were analysed from the fruiting body of P. giganteus. Three bacterial strains (Salmonella typhimurium, Staphylococcus aureus and Bacillus subtilis) were used to check the antibacterial activity of P. giganteus. Results: Pleurotus giganteus was characterised on basis of morpho-molecular techniques. High nutritional value contents like carbohydrate (32.4 g 100 g-1 d.wt.) and high protein (25.3 g 100 g-1 d.wt.) and elements like potassium, zinc and magnesium were found in Pleurotus giganteus. Phenol (17.7mg GAE g-1) and flavonoid (9.56 mg QE g-1) contents were recorded in high concentration, along with strong DPPH radical scavenging activity (IC50-235.01 µg m l-1). The maximum antibacterial activity was showed by Salmonella typhimurium. Twenty bioactive compounds were detected through GC-MS analysis, among them the maximum area was shown by cis-13-octadecenoic acid, followed byn-hexadecanoic acid and ergosterol. Interpretation: P. giganteus is a nutritionally rich edible mushroom with strong antioxidant and antibacterial potential. It is a reservoir of natural compounds that will be an alternative for synthetic drugs. Key words: Antibacterial, DPPH, ITS, Pleurotus giganteus