The isolation of two diarylnonanoids from Dioscorea cotinifolia possessing antibiotic-potentiating activity against resistant strains of S. aureus are reported. The diarylnonanoids are a class of natural products similar in structure to the diarylheptanoids, which have a wide spectrum of reported biological activities. One of the diarylnonanoids (1) isolated possesses a chiral center, and to deduce its configuration, the modified Mosher ester method was used. Using both 1D and 2D NMR data, as many protons as possible were assigned to both the R- and S-MTPA esters, and the configuration of the chiral center in 1 was determined to be R. Both the chiral and achiral diarylnonanoid (2) exhibited potent antibiotic-potentiating activity with the chiral natural product showing a greater tetracycline-potentiating activity than 2. Interestingly, 2 gave a higher norfloxacin-potentiating activity with a resultant higher efflux pump inhibitory activity. Manipulation of the structure of the diarylnonanoids through synthesis could lead to improved biological activity.

中文翻译：

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增强对 MRSA 的抗生素活性的两种薯蓣属物种的成分。

据报道，从薯蓣中分离出两种二芳基壬酸，它们对金黄色葡萄球菌的耐药菌株具有抗生素增强活性。二芳基壬烷类化合物是一类结构与二芳基庚烷类化合物相似的天然产物，具有广泛的生物活性报道。分离出的二芳基壬烷类化合物 (1) 之一具有手性中心，为了推断其构型，使用了改进的 Mosher 酯方法。使用 1D 和 2D NMR 数据，将尽可能多的质子分配给 R-和 S-MTPA 酯，并且确定 1 中手性中心的构型为 R。手性和非手性二芳基壬烷 (2)表现出有效的抗生素增强活性，手性天然产物显示出比 2 更大的四环素增强活性。有趣的是，2 产生更高的诺氟沙星增强活性，从而产生更高的外排泵抑制活性。通过合成操纵二芳基壬酸的结构可以提高生物活性。