Faculty of Agriculture, Food Science Department, Cairo University , Giza , Egypt.
Prep Biochem Biotechnol. 2019;49(9):876-883. doi: 10.1080/10826068.2019.1633667. Epub 2019 Jun 27.
Box-Behnken Design (BBD) was used to optimize the extraction conditions of polyphenols from Malva ( L.) leaves. The effect of ethanol concentration (20-80%), solvent/leaf powder ratio (10:1 to 30:1, v/w) and extraction time (5-45 min) on the polyphenols yield and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the obtained extracts were investigated. Quadratic models fit well. The optimal conditions (53.40% ethanol, solvent/leaf powder ratio 20:1 (v/w), and 15 min) resulted in an extract with a maximum yield of polyphenols (1098.4 mg GAE/100 g leaf powder) and high inhibition percentage of DPPH radical (33.31%) with desirability 0.742. High Performance Liquid Chromatography (HPLC) analysis indicated that the major identified polyphenol compounds extracted at the optimal conditions were naringenin, ρ-coumaric acid, apigenin-7-glucoside, luteolin, and cinnamic acid. These findings indicate that leaf extracts possess DPPH radical scavenging activity and could be used as a natural source for bioactive products.
Box-Behnken 设计（BBD）用于优化锦葵（Malva（L.））叶中多酚的提取条件。考察了乙醇浓度（20-80%）、溶剂/叶粉比（10:1 至 30:1，v/w）和提取时间（5-45min）对提取物中多酚产率和 2,2-二苯基-1-苦基肼（DPPH）自由基清除活性的影响。二次模型拟合良好。最佳条件（53.40%乙醇、溶剂/叶粉比 20:1（v/w）和 15min）得到的提取物具有最高的多酚产率（1098.4mg GAE/100g 叶粉）和高 DPPH 自由基抑制率（33.31%），理想度为 0.742。高效液相色谱（HPLC）分析表明，在最佳条件下提取的主要鉴定多酚化合物为柚皮素、对香豆酸、芹菜素-7-葡萄糖苷、木樨草素和肉桂酸。这些发现表明，叶提取物具有 DPPH 自由基清除活性，可作为生物活性产品的天然来源。
