Phytochemical Screening and Antioxidant activity of selected wild edible and cultivated Mushrooms of nepal

Abstract

Wild edible mushrooms have been widely used as nutrient-rich food since ancient times, and some of them are also produced on an industrial scale. In this study, the three most common cultivated mushrooms (Agaricus bisporus, Lentinula edodes and Pleurotus ostreatus) and three wild edible mushrooms (Scleroderma cepa, Termitomyces microcarpus and Termitomyces schimperi) were selected for the study. The objectives of the study were to analyze and compare the bioactive compounds present and antioxidant activity of wild edible and commonly cultivated mushrooms. The Total Phenolic Content value was estimated by using the Folin-Ciocalteu method. To determine the antioxidant potential of the samples, DPPH (2, 2-Diphenyl-1picrylhydrazyl)

and ABTS (2, 2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) scavenging assays were employed. From the preliminary phytochemical screening, it was observed that both wild and cultivated mushrooms tend to contain bioactive compounds such as Alkaloids, Steroids, Terpenoids, Polyphenols, Cardiac glycosides, and Saponins. Methanolic extracts of all three wild mushrooms exhibited higher TPC than the cultivated mushrooms. Highest TPC was found in water extract of S. cepa with the value of 36.57±0.81 mg GAE/ g dry extract. Lowest TPC was found in methanol extract of cultivated mushroom, A. bisporus with the value of 11.60±0.08 mg GAE/ g dry extract. The antioxidant assay revealed that all three wild mushrooms are strong inhibitors of free radicals like DPPH with the lowest IC50 values than the cultivated mushrooms. But in the case of ABTS assay, only S. cepa and T. microcarpus had a lowest IC50 values than other mushroom samples. Lowest IC50 value in inhibiting DPPH radical was observed in methanolic extract of S. cepa with a value of 0.744 mg/mL. And, lowest IC50 value in inhibiting ABTS radical was also found in water extract of S. cepa with the value of 0.583 mg/mL. This study revealed that there was a correlation between the TPC and ABTS radical scavenging potential of the samples. But no significant correlation could observed in the DPPH radical scavenging assay. Further study should focus on exploring many other edible mushrooms and identifying specific antioxidant compound present in them. But, initial focus of the study should focus on the toxicity of wild mushrooms because many mushrooms in the wild could be poisonous to human kind. Keywords: Bioactive compounds, total phenolic content, S. cepa, T. microcarpus, T. schimperi