Abstract

Grapevine leaves are used in the cuisines in the countries surrounding the Mediterranean and in folk medicine. They contain a huge amount of phenolic constituents. To optimize the extraction of bioactive compounds present in grapevine leaves, two methods of extraction were compared: conventional solvent extraction (CSE) and microwave-assisted extraction (MAE). The optimal extraction conditions in term of total phenolic content (TPC) were determined using a Box–Behnken design (BBD) from leaves of Vitis vinifera L. cv. Le tizourine Bou Afraraet. Optimal extraction conditions for CSE was 29% concentration of ethanol (v/v), 30.96 min extraction time, and 72:1 liquid-to-solid ratio (mL:g), at 37.5 °C. For MAE it was 34% concentration of ethanol(v/v), 474 W microwave power, 47 s irradiation time and 40:1 liquid-to-solid ratio (mL:g). Both extracts obtained by optimized MAE and CSE processes were compared in terms of total flavonoid content (TFC) and antioxidant activities (DPPH, ORAC, PFRAP and ICA). The MAE extract exhibited highest phenolic content and antioxidant activities. Moreover, phenolic compounds from leaves of Vitis vinifera L. cv. Ahmar-Bou-Amar were extracted following MAE optimal conditions and compared to Le tizourine Bou Afraraet extract. In addition to TPC and antioxidant activities, phenolic constituents were determined using HPLC–DAD-IT-MS and UPLC-QqQ-MS/MS. A total of sixteen phenolic compounds were identified and quantified including two phenolic acids, seven flavonols, three flavanols and four stilbenes. The obtained data revealed that the leaves of two native Algerian grapevines are rich in bioactive constituents, and can constitute by-products with added-value for food supplements.

Graphic abstract

中文翻译：

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传统溶剂提取和微波辅助提取的葡萄叶提取物的酚含量和抗氧化活性

摘要

葡萄叶用于地中海沿岸国家的美食以及民间医学。它们包含大量的酚类成分。为了优化提取葡萄叶中存在的生物活性化合物，比较了两种提取方法：常规溶剂提取（CSE）和微波辅助提取（MAE）。使用Box-Behnken设计（BBD）从葡萄树的叶子中确定总酚含量（TPC）的最佳提取条件L.简历 Le tizourine Bou Afraraet。CSE的最佳萃取条件是在37.5°C下29％的乙醇浓度（v / v），30.96分钟的萃取时间和72：1的液固比（mL：g）。对于MAE，浓度为34％的乙醇（v / v），474 W微波功率，47 s辐照时间和40：1的液固比（mL：g）。比较了通过优化的MAE和CSE工艺获得的两种提取物的总类黄酮含量（TFC）和抗氧化剂活性（DPPH，ORAC，PFRAP和ICA）。MAE提取物表现出最高的酚含量和抗氧化活性。此外，葡萄叶中的酚类化合物L.简历 按照MAE最佳条件提取Ahmar-Bou-Amar，并将其与Le tizourine Bou Afraraet提取物进行比较。除TPC和抗氧化剂活性外，还使用HPLC-DAD-IT-MS和UPLC-QqQ-MS / MS测定了酚类成分。共鉴定和定量了十六种酚类化合物，包括两种酚酸，七种黄酮醇，三种黄烷醇和四种对苯二酚。获得的数据表明，两个阿尔及利亚本土葡萄的叶子富含生物活性成分，并且可以构成副产品，具有食品补充剂的附加值。

图形摘要