Amino Acid Profiles and Bioactive Compounds of Four Inedible Mushrooms from Oban Division of Cross River National Park (CRNP), Nigeria

Inedible mushrooms are endowed with diverse nutritional and nutraceutical compounds. In this study, the amino acid profile, and phytochemical fingerprints of four selected wild inedible mushroom species from Oban Division of Cross River National Park (CRNP), Nigeria including Crepidotus applanatus (Pers.) P. Kumm, Daldinia concentrica (Bolton) Cesati & de Notaris, Oxyporus populinus (Schumach.) Donk and Trametes versicolor (L.) Lloyd were investigated. The fresh sporocarps of study mushroom were collected from the decaying wood during July 2018. Samples for amino acids profiling were dried to constant weight, defatted, hydrolyzed, evaporated in a rotary evaporator and loaded into the cartridge of the Applied Biosystems PTH Amino Acid Analyzer and analyzed for 45 minutes. The samples for phytochemical analysis were subjected to methanol extraction using a Soxhlet extractor and rotatory evaporator and injected into the column of an Agilent gas chromatography mass spectrometer (GCMS). The results of amino acid analysis revealed the presence of ten essential and eight non-essential amino acids in varying quantities across the species. The total amino acid content was highest in C. applanatus followed by D. concentrica, T. versicolor, and O. populinus in decreasing order. Glutamic acid, Arginine, and Aspartic acid were present in the highest amounts while Cystine, Lysine, and Histidine were the least across the species. The phytochemical screening of the samples led to the identification of 24 different compounds in D. concentrica, six compounds each in C. applanatus and O. populinus and three compounds in T. versicolor. In terms of percentage composition, 4H-Imidazo(1,5-a)(1,4)benzodiazepine-3-carboxylic acid, 5,6-dihydro-5-methyl-6-oxo-, ethyl ester, 1-Methylbicyclo[3.2.1]octane, Acetamide, N-(6-acetylaminobenzothiazol-2-yl)-2-(adamantan-1-yl)- and 9,19-Cyclolanost-24-en-3-ol, (3.beta.)-,TMS derivative were the most dominant compounds in C. applanatus, D. concentrica and T. versicolor respectively. The identified compound reportedly shows diverse bioactive activities, including antiviral, anticancer, antioxidant, hypocholesterolemic, anaphylactic, neurostimulant, pesticidal, insecticide and insecticidal activities. This data may represent the baseline information on the amino acid profiles and bioactive constituents of inedible mushroom species from Nigeria, as sources of noble compounds of substantial nutritional, medicinal and agricultural importance.