title: A novel antibacterial compound from Siegesbeckia glabrescens.
abstract: The crude methanol extract of the dried aerial parts of Siegesbeckia glabrescens (Compositae) showed antibacterial activity against the foodborne pathogen Staphylococcus aureus. Bioactivity-guided separation led to the isolation of 3-(dodecanoyloxy)-2-(isobutyryloxy)-4-methylpentanoic acid from nature for the first time. The structure was determined by spectroscopic data analysis (UV, MS, and NMR). The minimal inhibitory concentration (MIC) of 3-(dodecanoyloxy)-2-(isobutyryloxy)-4-methylpentanoic acid against S. aureus was found to be 3.12 &#956;g/mL. In addition, in a further antimicrobial activity assay against Gram-positive (B. subtilis, E. faecalis, P. acnes, S. epidermidis, S. schleiferi subsp. coagulans, S. agalactiae and S. pyrogens), and Gram-negative bacteria (E. coli and P. aeruginosa), and yeast strains (C. alibicans and F. neoformans), the antimicrobial activity of the compound was found to be specific for Gram-positive bacteria. The MIC values of the compound for Gram-positive bacteria ranged from 3.12 to 25 mg/mL. Furthermore, it was found that the 2-(isobutyryloxy)-4-methylpentanoic acid substituent may operate as a key factor in the antibacterial activity of the compound, together with the laurate group.
authors.affiliation: Biospectrum Life Science Institute, Seongnam City, Gyunggi Do, Korea.
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Kim
authors.forename: Hyungil
authors.initials: H
authors.lastname: Kim
authors.forename: Eunsun
authors.initials: E
authors.lastname: Jung
authors.forename: Jang-Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Wangtaek
authors.initials: W
authors.lastname: Hwang
authors.forename: Eun-Ju
authors.initials: EJ
authors.lastname: Kang
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Lee
authors.forename: Byung-Jo
authors.initials: BJ
authors.lastname: Ha
authors.forename: Jongsung
authors.initials: J
authors.lastname: Lee
authors.forename: Deokhoon
authors.initials: D
authors.lastname: Park
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000935:Antifungal Agents / Q000302:isolation & purification / Q000494:pharmacology; D019659:Asteraceae / Q000737:chemistry*; D006090:Gram-Negative Bacteria / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D010421:Pentanoic Acids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D035261:Plant Components, Aerial / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D015003:Yeasts / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D010421:Pentanoic Acids; D010936:Plant Extracts