murucoidin-v and operculinic-acid

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.

Topics: Acylation; Anti-Bacterial Agents; Bacteria; Caprylates; Cinnamates; Cross Infection; Escherichia coli; Esterification; Flowers; Glycosides; Herb-Drug Interactions; Ipomoea; Lactones; Methicillin-Resistant Staphylococcus aureus; Molecular Structure; Oligosaccharides; Plant Extracts; Salmonella enterica; Shigella flexneri

The CHCl(3)-soluble extract from the flowers of the Mexican medicinal plant Ipomoea murucoides, through preparative-scale recycling HPLC, yielded murucoidins I-V (1-5), which are new pentasaccharides of jalapinolic acid, as well as the known stoloniferin I (6). Saponification of the crude resin glycoside mixture yielded two glycosidic acids, simonic acid B (9) and operculinic acid A (10), and their esterifying residues were composed of the two short-chain fatty acids, 2-methylpropanoic and (2S)-methylbutyric acids. All the isolated compounds (1-6) were characterized through high-field NMR spectroscopy. Compound 4 exhibited marginal cytotoxicity against Hep-2 cells (ED(50) 4 microg/mL).

Topics: Antineoplastic Agents, Phytogenic; Carbohydrate Sequence; Drug Screening Assays, Antitumor; Flowers; Glycosides; Humans; Ipomoea; Mexico; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Plants, Medicinal; Resins, Plant; Tumor Cells, Cultured