Amino acids and antioxidant activities of extracts from wild edible mushrooms from a community forest in the Nasrinual District, Maha Sarakham, Thailand

Abstract Twenty two species of wild edible mushrooms were collected from Nasrinual community forest. The levels of 15 amino acids, antioxidant activity, and γ-aminobutyric acid (GABA) were determined. The 8 essential amino acids were arginine, histidine, isoleucine, leucine, lysine, phenylalanine, threonine, and valine, that they were found in all the mushrooms at concentration ranges of 0.28-2.14, 0.11-0.8, 0.19-1.33, 0.33-2.22, 0.22-1.73, 0.18-1.09, 0.31-1.83, and 0.23-1.66 g/100 g dw, respectively. The greatest and smallest amount of total amino acids, 28.41 and 5.76 g/100 g dw, were found in Hed-Peung-No5 and Hed-Klum-Ma, respectively. The antioxidants from the mushroom extracts obtained by water and 60% methanol and their activities were evaluated. It was found that flavonoids content and DPPH in methanol extracts were higher than in water extracts. In contrast, the phenolic content and FRAP activity in water extracts were higher than those in methanol extracts. Total phenolic, FRAP, and flavonoids content were highest in the extracts of Hed-Peung-No2, but the DPPH activity was highest in the extracts from Hed-Peung-No3. The GABA content was higher in the extracts obtained by hot water than it was in the extracts obtained by methanol. The highest GABA content was from water extract of Hed-Sai-duan (23.304 ± 0.027 mg/g dw).

摘要：本研究从纳斯里努尔（Nasrinual）社区森林中采集了22种野生食用蘑菇。本研究测定了15种氨基酸、抗氧化活性以及γ-氨基丁酸（γ-aminobutyric acid, GABA）的含量水平。本次检测的8种必需氨基酸分别为精氨酸、组氨酸、异亮氨酸、亮氨酸、赖氨酸、苯丙氨酸、苏氨酸及缬氨酸，所有供试蘑菇中均检出上述氨基酸，其含量范围依次为0.28~2.14、0.11~0.8、0.19~1.33、0.33~2.22、0.22~1.73、0.18~1.09、0.31~1.83及0.23~1.66 g/100g干重。总氨基酸含量最高与最低的样品分别为Hed-Peung-No5和Hed-Klum-Ma，其含量依次为28.41 g/100g干重与5.76 g/100g干重。本研究对水提法与60%甲醇提法制备的蘑菇提取物及其抗氧化活性进行了评估。研究发现，甲醇提取物中的黄酮类物质含量与DPPH自由基清除活性均高于水提取物；与之相反，水提取物中的酚类物质含量与FRAP抗氧化活性均优于甲醇提取物。Hed-Peung-No2提取物的总酚含量、FRAP活性与黄酮类物质含量均为最高，而Hed-Peung-No3提取物的DPPH自由基清除活性则最高。热水提取物中的GABA含量高于甲醇提取物。GABA含量最高的样品为Hed-Sai-duan的水提取物，其含量为23.304±0.027 mg/g干重。