Grapes contain high contents of phenolics, which are known to possess health promoting properties. Exogenous application of phytoregulators, mainly methyl jasmonate and abscisic acid, to grapevines to enhance phenolic content has been reported (Portu et al. Sci Hortic 240: 378-386, 2018 ; Ranjbaran et al. J Faculty Agric Kyushu Univ 56: 263-267, 2011 ). However, these phytohormones possess some drawbacks that can be overcome by using other phytoregulators as an alternative. In this work the effect of an additional phytohormone, salicylic acid, to grapevines on the phenolics and antioxidant activity of grapes was investigated. To our knowledge, salicylic acid has been earlier applied to grapevines to affect grape ripening and quality (Lóay. Egyptian J Basic Applied Sci 4: 227-230, 2017 ). However, this is the first time it is applied to increase the total phenolic content. As a result of our study, total phenol content and the free radical scavenging activity increased with 100 mg l −1 of salicylic acid. In particular, the total phenol content increased from 768.3 to 1843.5 mg 100 g −1 and the IC 50 values decreased from 45.2 to 13.2 mg ml −1 . Also the contents of individual phenolics mostly increased significantly with 100 mg l −1 of salicylic acid, except anthocyanins. Higher concentrations of salicylic acid (ie, 500 mg l −1 vs 100 mg l −1 ) did not result in higher contents of phenolics. Therefore, 100 mg l −1 was selected as the best salicylic acid concentration to be used in the treatment. The application of exogenous salicylic acid to grapevines is an interesting agronomic practice to obtain table grapes with improved health-promoting properties.

中文翻译：

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外源性水杨酸提高鲜食葡萄的酚类含量和抗氧化活性

葡萄含有高含量的酚类物质，众所周知，酚类物质具有促进健康的特性。已经报道了植物调节剂（主要是茉莉酸甲酯和脱落酸）外源性应用到葡萄藤以提高酚类含量（Portu 等人 Sci Hortic 240：378-386，2018 年；Ranjbaran 等人，J Faculty Agric Kyushu Univ 52676 ，2011 年）。然而，这些植物激素具有一些缺点，可以通过使用其他植物调节剂作为替代品来克服这些缺点。在这项工作中，研究了额外的植物激素水杨酸对葡萄藤对葡萄酚类物质和抗氧化活性的影响。据我们所知，水杨酸较早被应用于葡萄藤以影响葡萄的成熟和品质（Lóay.Egyptian J Basic Applied Sci 4: 227-230, 2017）。然而，这是第一次应用它来增加总酚含量。作为我们研究的结果，总酚含量和自由基清除活性随着 100 mg l -1 水杨酸的增加而增加。特别是，总酚含量从 768.3 增加到 1843.5 mg 100 g -1 ，IC 50 值从 45.2 减少到 13.2 mg ml -1 。此外，除了花青素外，100 mg l -1 水杨酸的单个酚类物质的含量大多显着增加。较高浓度的水杨酸（即，500 mg l -1 对 100 mg l -1 ）不会导致酚类物质的含量更高。因此，选择100 mg l -1 作为治疗中使用的最佳水杨酸浓度。