title: Structures of new phenolics isolated from licorice, and the effectiveness of licorice phenolics on vancomycin-resistant Enterococci.
abstract: Licorice, which is the underground part of Glycyrrhiza species, has been used widely in Asian and Western countries as a traditional medicine and as a food additive. Our continuous investigation on the constituents of roots and stolons of Glycyrrhiza uralensis led to the isolation of two new phenolics, in addition to 14 known compounds. Structural studies including spectroscopic and simple chemical derivatizations revealed that both of the new compounds had 2-aryl-3-methylbenzofuran structures. An examination of the effectiveness of licorice phenolics obtained in this study on vancomycin-resistant strains Enterococcus faecium FN-1 and Enterococcus faecalis NCTC12201 revealed that licoricidin showed the most potent antibacterial effects against both of E. faecalis and E. faecium with a minimum inhibitory concentration (MIC) of 1.9 × 10-5 M. 8-(γ,γ-Dimethylallyl)-wighteone, isoangustone A, 3'-(γ,γ-dimethylallyl)-kievitone, glyasperin C, and one of the new 3-methyl-2-phenylbenzofuran named neoglycybenzofuran also showed potent anti-vancomycin-resistant Enterococci effects (MIC 1.9 × 10-5-4.5 × 10-5 M for E. faecium and E. faecalis). The HPLC condition for simultaneous detection of the phenolics in the extract was investigated to assess the quality control of the natural antibacterial resource, and quantitative estimation of several major phenolics in the extract with the established HPLC condition was also performed. The results showed individual contents of 0.08%-0.57% w/w of EtOAc extract for the major phenolics in the materials examined.
authors.affiliation: Department of Natural Product Chemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan. eerdun3@163.com.
authors.lastname: Eerdunbayaer
authors.affiliation: Department of Natural Product Chemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan. m_a_orabi@yahoo.com.
authors.forename: Mohamed A A
authors.initials: MA
authors.lastname: Orabi
authors.affiliation: Department of Natural Product Chemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan. ph20101@s.okayama-u.ac.jp.
authors.forename: Hiroe
authors.initials: H
authors.lastname: Aoyama
authors.affiliation: Drug Discovery and Technology Center, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan. tkuroda@cc.okayama-u.ac.jp.
authors.forename: Teruo
authors.initials: T
authors.lastname: Kuroda
authors.affiliation: Department of Natural Product Chemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan. hatano@pharm.okayama-u.ac.jp.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hatano
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D006035:Glycyrrhiza / Q000737:chemistry*; D006801:Humans; D062385:Hydroxybenzoates / Q000008:administration & dosage / Q000737:chemistry*; D007529:Isoflavones / Q000737:chemistry; D008519:Medicine, Traditional; D008826:Microbial Sensitivity Tests; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D014640:Vancomycin / Q000494:pharmacology; D065507:Vancomycin-Resistant Enterococci / Q000187:drug effects; D000094162:Phytoalexins
chemical_list: D000900:Anti-Bacterial Agents; D062385:Hydroxybenzoates; D007529:Isoflavones; D010636:Phenols; D010936:Plant Extracts; D014640:Vancomycin; C094208:kievitone; D000094162:Phytoalexins; C017616:phenolic acid