Antioxidant Properties, Bioactive Compounds Contents, and Chemical Characterization of Two Wild Edible Mushroom Species from Morocco: Paralepista flaccida (Sowerby) Vizzini and Lepista nuda (Bull.) Cooke.

Abstract

Mushrooms have been consumed for centuries and have recently gained more popularity as an important source of nutritional and pharmaceutical compounds. As part of the valorization of mushroom species in northern Morocco, the current study aimed to investigate the chemical compositions and antioxidant properties of two wild edible mushrooms, Paralepista flaccida and Lepista nuda. Herein, the bioactive compounds were determined using spectrophotometer methods, and results showed that the value of total phenolic content (TPC) was found to be higher in P. flaccida (32.86 ± 0.52 mg) than in L. nuda (25.52 ± 0.56 mg of gallic acid equivalents (GAEs)/mg of dry methanolic extract (dme)). On the other hand, the value of total flavonoid content (TFC) was greater in L. nuda than in P. flaccida, with values of 19.02 ± 0.80 and 10.34 ± 0.60 mg of (+)-catechin equivalents (CEs)/g dme, respectively. Moreover, the ascorbic acid, tannin, and carotenoids content was moderate, with a non-significant difference between the two samples. High-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis allowed the identification and quantification of thirteen individual phenolic compounds in both P. flaccida and L. nuda, whereas p-Hydroxybenzoic acid was recognized as the major compound detected, with values of 138.50 ± 1.58 and 587.90 ± 4.89 µg/g of dry weight (dw), respectively. The gas chromatography-mass spectrometry (GC-MS) analysis of methanolic extracts of P. flaccida and L. nuda revealed the presence of sixty-one and sixty-six biomolecules, respectively. These biomolecules can mainly be divided into four main groups, namely sugars, amino acids, fatty acids, and organic acids. Moreover, glycerol (12.42%) and mannitol (10.39%) were observed to be the main chemical compositions of P. flaccida, while L. nuda was predominated by linolelaidic acid (21.13%) and leucine (9.05%). L. nuda showed a strong antioxidant property, evaluated by DPPH (half maximal effective concentration (EC50) 1.18-0.98 mg/mL); β-carotene bleaching (EC50 0.22-0.39 mg/mL); and reducing power methods (EC50 0.63-0.48 mg/mL), respectively. These findings suggested that both mushrooms are potential sources of various biomolecules, many of which possess important biological activities which are interesting for the foods and pharmaceuticals industry.