title: Antibacterial activity-guided purification and identification of a novel C-20 oxygenated ent-kaurane from Rabdosia serra (MAXIM.) HARA.
abstract: The objective of this work was to conduct an activity-guided isolation of antibacterial compounds from Rabdosia serra. The ethanol extracts of R. serra leaf and stem were partitioned sequentially into petroleum ether, ethyl acetate, butanol and water fractions, respectively. The ethanol extract of leaf evidenced broad-spectrum antibacterial activity against gram-positive bacterial, including Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Listeria monocytogenes. The ethyl acetate fractions of leaf and stem exhibited strong inhibition against gram-positive bacteria, and were then purified further. On the basis of antibacterial assay-guided purification, three phenolic compounds (rosmarinic acid, methyl rosmarinate and pedalitin) and four C-20 oxygenated ent-kauranes (effusanin E, lasiodin, rabdosichuanin D and a new compound namely effusanin F) were obtained, whose contents were determined by HPLC analysis. The broth microdilution method confirmed the important inhibition potential of C-20 oxygenated ent-kauranes with low minimum inhibitory concentration (MIC) values. Effusanin E, lasiodin and effusanin F could be useful for the development of new antibacterial agents.
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China.
authors.forename: Lianzhu
authors.initials: L
authors.lastname: Lin
authors.forename: Dashuai
authors.initials: D
authors.lastname: Zhu
authors.forename: Linwu
authors.initials: L
authors.lastname: Zou
authors.forename: Bao
authors.initials: B
authors.lastname: Yang
authors.forename: Mouming
authors.initials: M
authors.lastname: Zhao
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D045786:Diterpenes, Kaurane / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D037602:Isodon / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D045786:Diterpenes, Kaurane; D010636:Phenols; D010936:Plant Extracts