省產青花菜不同部位之抗氧化性   全文下載

Antioxidant Properties of the Extracts from Different Parts of Broccoli in Taiwan

本研究將省產青花菜（Brassica oleracea L var italica Plenca, broccoli）分為花、莖、葉三部分，經由冷凍乾燥處理之後，利用甲醇、水、丙酮三種溶劑萃取，並測其萃取液之抗氧化性。抗氧化性測定項目包括還原力、亞鐵離子螯合能力及α,α-diphenyl-β-picrylhydrazyl（DPPH）自由基之清除能力，並與BHA及alphatocopherol作比較。在還原力方面，花、莖、葉之甲醇及水萃取液均有良好之還原能力，其中以莖萃取液之還原能力最強，約為alpha-tocopherol 及BHA之1.3 倍；其次為葉萃取液，其還原力與alpha-tocopherol 及BHA相當；花萃取液之還原力較差，約為alpha-tocopherol 及BHA之四分之三。丙酮之萃取效果不佳。在亞鐵離子螯合能力方面，仍以甲醇及水之萃取效果較佳，丙酮之萃取效果不佳，而花、莖、葉三部分中以莖萃取液之螯合力最強，而莖之丙酮萃取液與alpha-tocopherol 及BHA一樣不具螯合力。在DPPH自由基的清除能力方面，花、莖、葉三部位均以甲醇之萃取效果最佳，其DPPH自由基的清除能力與alpha-tocopherol 及BHA相當，達90%以上，水萃取液之清除能力低於43%，丙酮萃取效果則不顯著。"

The flowers, stems, and leaves of broccoli (Brassica oleracea L var italica Plenca) cultivated in Taiwan were freeze-dried and extracted with methanol, water, or acetone. The antioxidant properties, including reducing power, ferrous ion chelating ability, and α,α-diphenyl- β-picrylhydrazyl (DPPH) radical scavenging activity, were tested in this study. The above antioxidant properties of broccoli extracts along with alpha-tocopherol and butylated hydroxyanisole (BHA) were compared. Results showed that the methanol and water extracts exhibited a higher reducing power in all three parts; while the acetone extract was the least. The stem extracts showed the highest reducing power, which was 1.3 times those alpha-tocopherol and BHA extracts, followed by the leaf extracts, which exhibited similar reducing power to alpha-tocopherol and BHA. The lowest reducing power was observed on flower extracts, which was only three fourth of the reducing power as compared to alpha-tocopherol and BHA. The methanol and water extracts of broccoli also exhibited high chelating ability; while the acetone extracts showed the lowest. The broccoli stem exhibited the highest chelating ability among three parts of broccoli. The acetone extracts from stems hardly showed any chelating ability as compared to alpha-tocopherol and BHA. The methanol extracts of broccoli showed the highest DPPH radical scavenging activity (>90%) among three different solvent extracts. Its DPPH radical scavenging activity was close to BHA and alpha-tocopherol. The water extracts showed only 43% DPPH radical scavenging activity; while the acetone extracts barely showed any DPPH radical scavenging activity. 本研究將省產青花菜（Brassica oleracea L var italica Plenca, broccoli）分為花、莖、葉三部分，經由冷凍乾燥處理之後，利用甲醇、水、丙酮三種溶劑萃取，並測其萃取液之抗氧化性。抗氧化性測定項目包括還原力、亞鐵離子螯合能力及α,α-diphenyl-β-picrylhydrazyl（DPPH）自由基之清除能力，並與BHA及alphatocopherol作比較。在還原力方面，花、莖、葉之甲醇及水萃取液均有良好之還原能力，其中以莖萃取液之還原能力最強，約為alpha-tocopherol 及BHA之1.3 倍；其次為葉萃取液，其還原力與alpha-tocopherol 及BHA相當；花萃取液之還原力較差，約為alpha-tocopherol 及BHA之四分之三。丙酮之萃取效果不佳。在亞鐵離子螯合能力方面，仍以甲醇及水之萃取效果較佳，丙酮之萃取效果不佳，而花、莖、葉三部分中以莖萃取液之螯合力最強，而莖之丙酮萃取液與alpha-tocopherol 及BHA一樣不具螯合力。在DPPH自由基的清除能力方面，花、莖、葉三部位均以甲醇之萃取效果最佳，其DPPH自由基的清除能力與alpha-tocopherol 及BHA相當，達90%以上，水萃取液之清除能力低於43%，丙酮萃取效果則不顯著。