The current study compared the radical scavenging and α-glucosidase inhibition potentials of ellagic acid (EA) and its metabolites, urolithins (Uros), and further explored the structure–activity relationship. The outcomes indicated that urolithin M5 (Uro-M5), EA, and urolithin M6 (Uro-M6) exhibited superior 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity; EA and urolithin D (Uro-D) expressed better ABTS scavenging ability, and EA and Uro-M5 showed preferable α-glucosidase inhibition activity. The results of CD spectra and fluorescence spectral analysis explained the interaction between Uros and α-glucosidase. Correlation analysis indicated that hydroxyl groups were crucial for the antioxidative effect, while C-8 OH contributed greatly to the α-glucosidase inhibition activity. Quantum mechanical analysis showed that both EA and Uros exhibited strong electrophilic properties. These comparative results showed a biological discrepancy between Uros and provided essential information for exploring the bioactive application of EA as a functional ingredient or dietary supplement.

中文翻译：

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鞣花酸及其代谢物尿石素体外抗氧化作用和 α-葡萄糖苷酶抑制潜力的比较研究


本研究比较了鞣花酸 （EA） 及其代谢物尿石素 （Uros） 的自由基清除和 α-葡萄糖苷酶抑制潜力，并进一步探讨了构效关系。结果表明，尿石素 M5 （Uro-M5） 、 EA 和尿石素 M6 （Uro-M6） 表现出优异的 2,2-二苯基-1-三硝基苯肼 （DPPH） 清除活性;EA 和尿石素 D （Uro-D） 表达较好的 ABTS 清除能力，EA 和 Uro-M5 表现出较好的 α-葡萄糖苷酶抑制活性。CD 光谱和荧光光谱分析的结果解释了 Uros 和 α-葡萄糖苷酶之间的相互作用。相关性分析表明，羟基对抗氧化作用至关重要，而 C-8 OH 对 α-葡萄糖苷酶抑制活性有很大贡献。量子力学分析表明，EA 和 Uros 都表现出很强的亲电特性。这些比较结果显示 Uros 之间存在生物学差异，并为探索 EA 作为功能性成分或膳食补充剂的生物活性应用提供了重要信息。