| 摘要: | 本研究的目的在探討菇類萃取物之抗氧化特性及萃取溶劑的影響，並研究菇類之酚類化合物含量及存在型態。以台灣五種市售之食用菇類（鴻喜菇、金針菇、杏鮑菇、珊瑚菇、香菇）為樣品，以兩種溶劑（100%甲醇、80%丙酮）萃取菇樣品之凍乾粉末，測定萃取物之抗氧化特性，包括DPPH自由基清除效力、還原力、清除超氧陰離子效應、總抗氧化活性；並定量抗氧化物質，包括酚類及花青素；此外，透過溶劑萃取、鹼水解和液相萃取方法探討酚類化合物的存在型態。結果顯示，菇類的丙酮與甲醇萃取物具有清除DPPH自由基活性、還原力及總抗氧化活性，而無清除超氧陰離子效應；抗氧化活性高低與菇的種類有關，此實驗的五種菇種中，以珊瑚菇及杏鮑菇的抗氧化活性最強。珊瑚菇含有最高酚類含量（7.36 mg/g），接著為杏鮑菇、香菇、鴻喜菇和金針菇。菇類中的酚類物質主要以游離態存在（鴻喜菇51%、金針菇75%、杏鮑菇70%、珊瑚菇56%、香菇69%）。以丙酮為溶劑之萃取物具有較高的抗氧化活性，且其萃取物之清除DPPH自由基活性與總酚含量具有顯著相關性（r^2=0.93），但DPPH清除活性對甲醇萃取物總酚含量的相關性則極低（r^2=0.15），此結果顯示丙酮與甲醇所萃取出的酚類化合物種類明顯不同。結果亦顯示，不論丙酮或甲醇的萃取物，五種菇類的花青素含量均低（≦0.11mg/g）。
The study was to investigate the antioxidant capacity, content and existing forms of phenolic compounds in solvent extracts from five commercial mushrooms, including Hypsizigus marmoreus, Flammulina velutipes, Pleurotus eryngii, Pleurotus citrinopoleatus Sing, and Lentinus edodes. As well as the influence of extracting solvents, acetone (80%) and methanol (100%) was evaluated by various antioxidant assays, including reducing power, radical scavenging, and total antioxidant activity. Both acetone and methanolic extracts of mushrooms exhibited antioxidant capacities in reducing power, DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging, and total antioxidant activity, but were not detectable in scavenging effect on hydroxyl radical. Among the five mushroom species, Pleurotus citrinopoleatus Sing, which contained the highest total phenol (7.36 mg/g), showed stronger antioxidant activity than the others. The phenolic compounds in the mushroom existed mainly in the free form (51% in H. marmoreus, 75% in F. velutipes, 70% in P. eryngii, 56% in P. citrinopoleatus Sing, and 69% in L. edodes). For all the antioxidant activity measurement, the acetone extract showed higher than methanol extract. In term of antioxidant activity, only DPPH free radical scavenging effect in acetone extract was significantly correlated to total phenol content (r^2=0.93). However, the correlation in the methanol extract was very low (r^2=0.15). On the basis of the results obtained, mushrooms are found to be a potential source of natural antioxidants. Nevertheless, the extracting solvent and antioxidant capacity measuring system should be considerable. Results also showed that, regardless of acetone or methanol extracts, anthocyanin contents of five mushrooms were low (≦0.11 mg/g). |
