Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510DF, Mexico.
Phytochemistry. 2013 Nov;95:277-83. doi: 10.1016/j.phytochem.2013.07.007. Epub 2013 Aug 3.
Reinvestigation of the CHCl3-soluble extract from the flowers of Ipomoea murucoides, through preparative-scale recycling HPLC, yielded three pentasaccharides of 11-hydroxyhexadecanoic acid, murucoidins XVII-XIX, in addition to the known murucoidin III and V, all of which were characterized by NMR spectroscopy and mass spectrometry. These compounds were found to be macrolactones of the known pentasaccharides simonic acid B and operculinic acid A. The acylating groups corresponded to acetic, (2S)-methyl-butyric, (E)-cinnamic and octanoic acids. The esterification sites were established at the C-2 of the second rhamnose and C-3 and C-4 of the third rhamnose. The aglycone lactonization was placed at C-2 or C-3 of the first rhamnose. Bioassays for modulation of antibiotic activity were performed against multidrug-resistant strains of Staphylococcus aureus, Escherichia coli Rosetta-gami, and two nosocomial pathogens: Salmonella enterica sv. Typhi and Shigella flexneri. The tested glycolipids did not act as cytotoxic (IC50>4 μg/mL) nor as antimicrobial (MIC>128 μg/mL) agents. However, they exerted a potentiation effect on clinically useful antibiotics against the tested bacteria by increasing their antibiotic susceptibility up to four-fold at concentrations of 25 μg/mL.
通过制备规模的再循环 HPLC 对大丽花 murucoides 花的 CHCl3 可溶提取物进行重新研究，除了已知的 murucoidin III 和 V 之外，还得到了三个 11-羟基十六烷酸的五糖，即 murucoidins XVII-XIX，它们均通过 NMR 光谱和质谱进行了表征。这些化合物被发现是已知的 pentasaccharides simonic acid B 和 operculinic acid A 的大环内酯。酰化基团对应于乙酸、(2S)-甲基丁酸、(E)-肉桂酸和辛酸。酯化位点位于第二个鼠李糖的 C-2 和第三个鼠李糖的 C-3 和 C-4。糖苷键内酯化发生在第一个鼠李糖的 C-2 或 C-3 上。针对耐多药金黄色葡萄球菌、大肠杆菌 Rosetta-gami 以及两种医院病原体：伤寒沙门氏菌和福氏志贺菌进行了抗生素活性调节的生物测定。测试的糖脂既没有表现出细胞毒性（IC50>4 μg/mL）也没有表现出抗菌作用（MIC>128 μg/mL）。然而，它们在 25 μg/mL 的浓度下对临床有用的抗生素对测试细菌的抗生素敏感性产生了增效作用，使其抗生素敏感性增加了四倍。
