Institute of TCM and Natural Products, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan 430071, China.
Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada.
Biomolecules. 2020 Feb 5;10(2):243. doi: 10.3390/biom10020243.
Grape seed extract (GSE) is a rich source of condensed flavonoid tannins, also called proanthocyanidins (PACs). The high molecular weight of polymeric PAC limits their biological activity due to poor bioavailability. The present study was undertaken to explore the potential applicability of microwave-assisted extraction (MAE) to convert GSE-PAC into monomeric catechins. A central composite design (CCD) was used to optimize the processing conditions for the MAE. The maximum total yield of monomeric catechins (catechin, epicatechin, and epicatechin gallate) and PAC were 8.2 mg/g dry weight (DW) and 56.4 mg catechin equivalence (CE)/g DW, respectively. The optimized MAE condition was 94% ethanol, 170 °C temperature, and a duration of 55 min. Compared to the results for PACs extracted via conventional extraction (Con) (94% ethanol; shaking at 25 °C for 55 min), MAE yielded 3.9-fold more monomeric catechins and 5.5-fold more PACs. The MAE showed higher antioxidant capacity and α-glucosidase inhibitory activity than that of the conventional extract, suggesting the potential use of the MAE products of grape seeds as a functional food ingredient and nutraceutical.
葡萄籽提取物 (GSE) 是一种富含缩合类黄酮单宁的物质，也称为原花青素 (PACs)。由于生物利用度差，高分子量的聚合型 PAC 限制了其生物活性。本研究旨在探索微波辅助提取 (MAE) 将 GSE-PAC 转化为单体儿茶素的潜在应用。采用中心复合设计 (CCD) 优化 MAE 的加工条件。单体儿茶素（表儿茶素、表没食子儿茶素和表没食子儿茶素没食子酸酯）和 PAC 的最大总产量分别为 8.2mg/g 干重 (DW) 和 56.4mg 表儿茶素当量 (CE)/g DW。最佳 MAE 条件为 94%乙醇、170°C 温度和 55 分钟的持续时间。与通过常规提取 (Con)（94%乙醇；在 25°C 下摇动 55 分钟）提取的 PACs 相比，MAE 产生的单体儿茶素增加了 3.9 倍，PACs 增加了 5.5 倍。MAE 显示出比常规提取物更高的抗氧化能力和α-葡萄糖苷酶抑制活性，表明葡萄籽 MAE 产物作为功能性食品成分和营养保健品的潜在用途。
