title: Isolation and identification of antialgal compounds from the leaves of Vallisneria spiralis L. by activity-guided fractionation.
abstract: OBJECTIVE
  Vallisneria spiralis Linn., a common submerged macrophyte, is widely available in quiet waters of lakes, ponds, marshes and streams in Southeast Asia. V. spiralis plays a significant role not only in decreasing eutrophication of water body for its productivity, but also in inhibiting the growth of blue-green algae? The aim of the paper involves the isolation and identification of allelochemicals from extracts of V. spiralis by activity-guided fractionation and column chromatography.
  
  
  METHODS
  Leaves of V. spiralis was washed free of debris, air-dried and refluxed in 95% EtOH. The extract was isolated using column chromatography and fractionation with antialgal activity. Potential allelochemicals were analyzed by high-resolution gas chromatography-mass spectrometry (HRGC-MS).
  
  
  RESULTS
  Two fractions with strong antialgal activity were isolated using column chromatography and activity-guided fractionation from the extract of V. spiralis. 2-Ethyl-3-methylmaleimide, dihydroactinidiolide and 4-oxo-beta-Ionone were identified in the first fraction, and 3-hydroxy-5,6-epoxy-beta-ionone, loliolide, 6-hydroxy-3-oxo-alpha-ionone and an unknown compound in the second fraction. They had strong inhibitory effects on Microcystis aeruginosa Kütz.
  
  
  CONCLUSIONS
  2-Ethyl-3-methylmaleimide is a byproduct of photooxidation of chlorophyll, and five other compounds identified were derivatives of beta-carotene. HRGC-MS and derivatization technology were used to identify and confirm their molecular structures. The formula of the unknown compound was C16H19NO4. Metabolites of plant pigments had strong inhibitory activities on growth of algae.
  
  
  CONCLUSIONS
  Six compounds had been identified in V. spiralis, among them, 2-ethyl-3-methylmaleimide was the main allelochemical, and derivatives of ionone were also potential allelochemicals.
  
  
  CONCLUSIONS
  The results of our research could help us to study further mechanisms of inhibitory effect on algae and develop new potential antialgal substances.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China. xianqm@nju.edu.cn
authors.forename: Qiming
authors.initials: Q
authors.lastname: Xian
authors.forename: Haidong
authors.initials: H
authors.lastname: Chen
authors.forename: Huili
authors.initials: H
authors.lastname: Liu
authors.forename: Huixian
authors.initials: H
authors.lastname: Zou
authors.forename: Daqiang
authors.initials: D
authors.lastname: Yin
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology; D002734:Chlorophyll / Q000737:chemistry; D056890:Eukaryota / Q000187:drug effects* / Q000254:growth & development; D008401:Gas Chromatography-Mass Spectrometry; D031321:Hydrocharitaceae / Q000737:chemistry*; D008301:Maleimides / Q000302:isolation & purification / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D046931:Microcystis / Q000187:drug effects* / Q000254:growth & development; D045792:Norisoprenoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010936:Plant Extracts / Q000302:isolation & purification* / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry
chemical_list: C474814:2-ethyl-3-methylmaleimide; D000900:Anti-Bacterial Agents; D008301:Maleimides; D045792:Norisoprenoids; D010936:Plant Extracts; D002734:Chlorophyll