Survey of Edible Amanita in Northern Thailand and Their Nutritional Value, Total Phenolic Content, Antioxidant and α-Glucosidase Inhibitory Activities

Several edible wild mushrooms are known to be a good source of essential dietary minerals, nutrients, and vitamins, which makes them an important source of food for humans. Edible wild mushrooms are extremely popular among consumers and are highly valued for their potential economic benefits in northern Thailand. In this present study, a total of 19 specimens of edible Amanita were collected during investigations of wild edible mushrooms in northern Thailand during the period from 2019 to 2022. Their morphological characteristics and the phylogenetic analyses indicated that the collected specimens belonged to A. hemibapha, A. pseudoprinceps, A. rubromarginata, and A. subhemibapha. Subsequently, nutritional compositions, total phenolic contents, as well as the antioxidant and α-glucosidase inhibitory activities of each species, were investigated. The results indicate that the protein contents in both A. pseudoprinceps and A. subhemibapha were significantly higher than in A. hemibapha and A. rubromarginata. The highest total phenolic content was found in the extract of A. pseudoprinceps. In terms of antioxidant properties, the extract of A. pseudoprinceps also exhibited significantly high antioxidant activity by 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1- picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. However, the extract of A. rubromarginata had the lowest total phenolic content and level of antioxidant activity. Additionally, α-glucosidase inhibitory activity varied for different Amanita species and the highest level of α-glucosidase inhibitory activity was found in the extract of A. pseudoprinceps. This study provides valuable information on the nutrient content, phenolic content and the antioxidant and α-glucosidase inhibitory potential of edible Amanita species found in northern Thailand.