The pickled radish can be kept at room temperature for years without spoilage. 2,6-dihydroxyacetophenone (DHAP), 4-hydroxybenzaldehyde (HBA), and 4-hydroxyphenethyl alcohol (4-HPEA) were first found from the pickled radish. The structures of three phenolic compounds were elucidated by analysis of their nuclear magnetic resonance and high-resolution electro-spray ionization mass spectrometry data. All these phenolic compounds showed good free radical scavenging capacity except HBA. Both DHAP and 4-HPEA also showed high ferric reducing ability. DHAP showed good antimicrobial activity against Escherichia coli, Bacillus subtilis, and Canidia albicans. HBA demonstrated antimicrobial activity against E. coli and C. albicans but not B. subtilis. Based on the results of MTT assay, these compounds did not show cytotoxicity to LO2 cell line. All results indicated the pickled radish had antioxidant and antimicrobial phenolic compounds. To the best of our knowledge, this report is the first to answer partially the question of why pickled foods can be kept at room temperature for years without spoilage based on the evidence of three phenolic compounds.

中文翻译：

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腌萝卜中具有抗氧化和抗菌活性的酚类化合物的提取和表征。

腌制的萝卜可以在室温下保存多年而不会变质。首先从腌制萝卜中发现2，6-二羟基苯乙酮（DHAP），4-羟基苯甲醛（HBA）和4-羟基苯乙醇（4-HPEA）。通过分析三种酚类化合物的核磁共振和高分辨率电喷雾电离质谱数据，阐明了它们的结构。除HBA外，所有这些酚类化合物均表现出良好的自由基清除能力。DHAP和4-HPEA均显示出高铁还原能力。DHAP对大肠杆菌，枯草芽孢杆菌和白色念珠菌具有良好的抗菌活性。HBA表现出对大肠杆菌和白色念珠菌的抗微生物活性，但对枯草芽孢杆菌则没有。根据MTT分析的结果，这些化合物对LO2细胞系没有细胞毒性。所有结果表明，腌萝卜具有抗氧化剂和抗菌酚类化合物。据我们所知，该报告是第一个部分回答关于为什么腌制食品可以在室温下保存多年而不会变质的问题，这是基于三种酚类化合物的证据。