State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China.
Food Funct. 2020 Jul 1;11(7):6517-6527. doi: 10.1039/d0fo00037j. Epub 2020 Jul 7.
In recent years, increasing research has evaluated the use of natural products as antimicrobial food additives. In this study, antibacterial activity was evaluated for six dihydrochalcone compounds from Malus. Phloretin and 3-hydroxyphloretin exhibited antibacterial effects on both Gram-positive and Gram-negative bacteria, and the antibacterial capacity of these compounds was greater than that of their glycosylated derivatives. Within a certain range, dihydrochalcone hydrophobicity was positively correlated with antibacterial activity. Additionally, glycosylation at the 2'-position of the A-ring and hydroxyl group at the 3-position of the B-ring played a key role in the antibacterial activity of dihydrochalcones. Phloretin and 3-hydroxyphloretin caused damage to bacterial cells by significantly increasing protein and inorganic phosphate leakage. Compared to phloretin, 3-hydroxyphloretin exhibited a smaller effect on Gram-positive Micrococcus luteus and a greater effect on Gram-negative Klebsiella pneumoniae, suggesting different antibacterial mechanisms. At a low dihydrochalcone concentration, the respiration of M. luteus did not change, while membrane permeability increased significantly. These results indicate that the antibacterial mechanism of M. luteus was primarily damage to the cell membrane. However, damage to respiration and the cell membrane might occur simultaneously in K. pneumoniae, suggesting that the antibacterial mechanism of dihydrochalcones also depends on strain type. This study demonstrated the broad-spectrum antibacterial properties of dihydrochalcone compounds commonly found in the genus Malus to foodborne pathogens and elucidated the antibacterial mechanisms. It provides theoretical guidance for future research and application of dihydrochalcones in the food industry.
近年来，越来越多的研究评估了天然产物作为抗菌食品添加剂的用途。在这项研究中，评估了来自苹果属的六种二氢查尔酮化合物的抗菌活性。根皮素和 3-羟基根皮素对革兰氏阳性菌和革兰氏阴性菌均具有抗菌作用，且这些化合物的抗菌能力强于其糖苷衍生物。在一定范围内，二氢查尔酮的疏水性与抗菌活性呈正相关。此外，A 环 2'-位的糖苷化和 B 环 3-位的羟基在二氢查尔酮的抗菌活性中起关键作用。根皮素和 3-羟基根皮素通过显著增加蛋白质和无机磷酸盐的渗漏对细菌细胞造成损伤。与根皮素相比，3-羟基根皮素对革兰氏阳性菌微球菌的作用较小，对革兰氏阴性菌肺炎克雷伯氏菌的作用较大，表明其具有不同的抗菌机制。在低浓度的二氢查尔酮下，M. luteus 的呼吸没有变化，但膜通透性显著增加。这些结果表明，M. luteus 的抗菌机制主要是破坏细胞膜。然而，在肺炎克雷伯氏菌中，呼吸和细胞膜的损伤可能同时发生，这表明二氢查尔酮的抗菌机制也取决于菌株类型。本研究证明了苹果属中常见的二氢查尔酮化合物对食源性病原体具有广谱抗菌特性，并阐明了其抗菌机制。这为未来在食品工业中二氢查尔酮的研究和应用提供了理论指导。
