Phenols are bioactive substances of great interest because of their involvement in plant physiology, their use in many industrial processes, and their impact on human health. This work aims to summarize the varied approaches to the phenolic analysis of chestnut (bark and wood of trunk and branches, leaves, catkins, burs, and fruit) and to collate the optimal conditions into an easy to follow and execute protocol. Phenolic compounds were extracted by solid–liquid extraction and separated by liquid–liquid extraction. Total phenols content was determined by Folin–Ciocalteu assay, condensed tannins by vanillin assay, and hydrolyzable tannins (gallotannins and ellagitannins) by high-performance liquid chromatography quantification of methyl gallate and ellagic acid following acid methanolysis. The lowest temperature for conservation (–80 ℃), lyophilization, and milling (liquid N2) were the most effective pretreatments for samples. For quantification of tannins, the use of water clearly reduced the sensitivity of the analysis of condensed tannins, whilst the more efficient degradation capacity of sulfuric acid improved the methanolysis of hydrolyzable tannins. These findings were validated using a range of chestnut tissues, and thus confirm the utility and effectiveness of this easy to implement, cost-effective, and efficient protocol.

中文翻译：

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板栗中酚类化合物的分析方法优化（Castanea sativa Mill。）

酚类是非常受关注的生物活性物质，因为它们参与植物生理学、在许多工业过程中的使用以及它们对人类健康的影响。这项工作旨在总结板栗（树干和树枝的树皮和木材、树叶、柳絮、车针和果实）的酚类分析的各种方法，并将最佳条件整理成易于遵循和执行的协议。酚类化合物采用固液萃取法提取，液液萃取法分离。总酚含量通过 Folin-Ciocalteu 测定法测定，缩合单宁通过香兰素测定法测定，可水解单宁（没食子单宁和鞣花单宁）通过酸性甲醇分解后没食子酸甲酯和鞣花酸的高效液相色谱定量测定。最低保存温度（–80 ℃），冻干和研磨（液氮）是对样品最有效的预处理。对于单宁的定量，水的使用明显降低了缩合单宁分析的灵敏度，而硫酸更有效的降解能力提高了可水解单宁的甲醇分解。这些发现使用一系列栗子组织进行了验证，从而证实了这种易于实施、具有成本效益且高效的协议的实用性和有效性。