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 μg/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.
Keywords: antibacterial activity; 3-(dodecanoyloxy)-2-(isobutyryloxy)-4-methylpentanoic acid; lauric acid; Siegesbeckia glabrescens
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Kim, Y.-S.; Kim, H.; Jung, E.; Kim, J.-H.; Hwang, W.; Kang, E.-J.; Lee, S.; Ha, B.-J.; Lee, J.; Park, D. A Novel Antibacterial Compound from Siegesbeckia glabrescens. Molecules 2012, 17, 12469-12477.
Kim Y-S, Kim H, Jung E, Kim J-H, Hwang W, Kang E-J, Lee S, Ha B-J, Lee J, Park D. A Novel Antibacterial Compound from Siegesbeckia glabrescens. Molecules. 2012; 17(11):12469-12477.
Kim, Young-Soo; Kim, Hyungil; Jung, Eunsun; Kim, Jang-Hyun; Hwang, Wangtaek; Kang, Eun-Ju; Lee, Sanghyun; Ha, Byung-Jo; Lee, Jongsung; Park, Deokhoon. 2012. "A Novel Antibacterial Compound from Siegesbeckia glabrescens." Molecules 17, no. 11: 12469-12477.