title: A new naphthoquinone and other antibacterial constituents from the roots of Xanthium sibiricum.
abstract: Reinvestigating the chemical constituents of the roots of Xanthium sibiricum led to the isolation of a new naphthoquinone (1), together with 13 known compounds (2-14). Their structures were elucidated by using spectroscopic analyses, including HR-ESI-MS, 1D and 2D NMR, and by comparing their NMR data with those of related compounds. Compound 1 showed moderate antibacterial activity against Escherichia coli, Bacillus subtilis, Micrococcus tetragenus and Staphylococcus aureus, while 6 and 12 showed stronger antibacterial activity than the positive control ciprofloxacin against E. coli, with minimum inhibitory concentration values of 0.17 and 0.35 μg/mL, respectively.
authors.affiliation: a Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education, College of Chemistry and Chemical Engineering, Hainan Normal University , Haikou 571158 , P. R. China.
authors.forename: Wen-Hao
authors.initials: WH
authors.lastname: Chen
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Song
authors.forename: Guang-Ying
authors.initials: GY
authors.lastname: Chen
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D009285:Naphthoquinones / Q000737:chemistry* / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry*; D031210:Xanthium / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D009285:Naphthoquinones; D010936:Plant Extracts
keywords: Xanthium sibiricum Patr; antibacterial activity; chemical constituents; compositae