Instituto de Investigaciones para la Industria Química (INIQUI-CONICET), Universidad Nacional de Salta, Salta, Argentina.
J Appl Microbiol. 2011 Sep;111(3):731-8. doi: 10.1111/j.1365-2672.2011.05070.x. Epub 2011 Jun 30.
To study the antimicrobial activity of naringin (NAR), a flavonoid extracted from citrus industry waste, and NAR derivatives [naringenin (NGE), prunin and alkyl prunin esters] against pathogenic bacteria such as L. monocytogenes, E. coli O157:H7 and S. aureus. The relationship between the structure of the chemical compounds and their antagonistic effect was also analysed.
The agar dilution technique and direct contact assaying were applied. NGE, prunin and NAR showed no antimicrobial activity at a concentration of 0.25 mmol l(-1). Similarly, fatty acids with a chain length between C2 and C18 showed no antimicrobial activity at the same concentration. However, prunin-6″-O-acyl esters presented high antibacterial activity, mainly against Gram-positive strains. This activity increased with increasing chain length (up to 10-12 carbon atoms). Alkyl prunin esters with 10-12 carbon atoms diminished viability of L. monocytogenes by about 3 log orders and S. aureus by 6 log orders after 2 h of contact at 37°C and at a concentration of 0.25 mmol l(-1). The compounds examined were not effective against any of the Gram-negative strains assayed, even at the highest concentration.
Addition of sugars to the aglycone did not enhance its antimicrobial activity. Attachment of a saturated aliphatic chain with 10-12 carbon atoms to the A ring of the flavonoid (or to sugars attached to this ring), seems to be the most promising modification. In conclusion, alkyl prunin esters with a chain length of C10-C12 have promising features as antimicrobial agents because of their high antilisterial and antistaphylococcal activity.
This study shows that it is possible to obtain NAR derivatives with important antimicrobial activity, especially against Gram-positive pathogenic bacteria. It also provides guidelines on the structural modifications in similar molecules to enhance the antimicrobial activity.
研究从柑橘工业废物中提取的类黄酮柚皮苷（NAR）及其衍生物[柚皮素（NGE）、普林和烷基普林酯]对单核细胞增生李斯特菌、大肠杆菌 O157：H7 和金黄色葡萄球菌等致病菌的抗菌活性。还分析了化合物结构与其拮抗作用之间的关系。
应用琼脂稀释技术和直接接触测定法。在 0.25mmol l(-1)浓度下，NGE、普林和 NAR 均没有抗菌活性。同样，在相同浓度下，链长在 C2 到 C18 之间的脂肪酸也没有抗菌活性。然而，普林-6″-O-酰酯具有很高的抗菌活性，主要针对革兰氏阳性菌株。这种活性随着链长的增加（最多 10-12 个碳原子）而增加。在 37°C 下，浓度为 0.25mmol l(-1)时，10-12 个碳原子的烷基普林酯在 2 小时内使单核细胞增生李斯特菌的活力降低了约 3 个对数级，使金黄色葡萄球菌的活力降低了 6 个对数级。在所测试的革兰氏阴性菌株中，即使在最高浓度下，这些化合物也没有效果。
在糖苷配基上添加糖并没有增强其抗菌活性。在黄酮（或连接到该环上的糖）的 A 环上连接一个 10-12 个碳原子的饱和脂肪链似乎是最有前途的修饰方法。综上所述，具有 C10-C12 链长的烷基普林酯具有很高的抗李斯特菌和抗葡萄球菌活性，是很有前途的抗菌剂。
本研究表明，可以获得具有重要抗菌活性的 NAR 衍生物，特别是对革兰氏阳性致病菌。它还为增强抗菌活性的类似分子的结构修饰提供了指导。
