Leaves from Olea europaea represent one of the main by-products of the olive oil industry, containing a plethora of bioactive compounds with several promising activities for human health. An organic solvent-free extraction method was developed for the recovery of olive leaf phenols, which obtained an extract containing oleuropein in high amounts. A comparison of various extraction media is reported, together with the total phenolic content, DPPH (2,2-Diphenyl-1-picrylhydrazyl) content, ORAC (oxygen radical absorbance capacity), and polyphenol oxidase activity of the corresponding extracts. The polyphenol profiles and content of the most representative extracts have also been studied. Extraction solvent and temperature significantly influenced the phenolic content and antioxidant activity of the extracts, with hot water representing the solvent of election for the extraction of bioactive compounds from this matrix. All the extracts obtained showed reasonably high total phenol content (TPC) and good DPPH radical scavenging activity; among them, the water extract is characterized by desirable traits and could be used for many industrial applications and human consumption.

中文翻译：

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用水作为从橄榄叶中提取富含橄榄苦苷的提取物的溶剂

油橄榄叶代表橄榄油行业的主要副产品之一，其中含有大量的生物活性化合物，对人类健康具有若干有希望的活性。开发了一种用于回收橄榄叶酚的无有机溶剂提取方法，该方法获得了含有大量橄榄苦苷的提取物。报告了各种提取介质的比较，以及相应提取物的总酚含量，DPPH（2,2-二苯基-1-吡啶并肼基）含量，ORAC（氧自由基吸收能力）和多酚氧化酶活性。还对最具代表性的提取物的多酚谱和含量进行了研究。提取溶剂和温度显着影响提取物中的酚含量和抗氧化活性，用热水代表从该基质中提取生物活性化合物的选择溶剂。所获得的所有提取物均显示出相当高的总酚含量（TPC）和良好的DPPH自由基清除活性。其中，水提取物具有理想的特性，可用于许多工业应用和人类消费。