title: Isolation and characterization of a novel antialgal allelochemical from Phragmites communis.
abstract: Antialgal allelochemicals were isolated from Phragmites communis Tris. The isolated allelopathic fraction showed strong inhibition activity on the growth of Chlorella pyrenoidosa and Microcystis aeruginosa but had no inhibition on Chlorella vulgaris. The 50% effective concentrations (EC50) of the allelopathic fractions on C. pyrenoidosa and M. aeruginosa were 0.49 and 0.79 mg/liter, respectively. The allelopathic activity of the fraction was species-specific. The isolated allelopathic fraction caused metal ion leakage from algal cells. The fraction decreased the activities of antioxidant enzymes, such as superoxide dismutase and peroxidase. The addition of the isolated fraction increased the concentration of unsaturated lipid fatty acids in cell membrane of C. pyrenoidosa and M. aeruginosa. This caused a change in plasma membrane integrity and the leakage of ions in the protoplast. The allelopathic compound was identified by nuclear magnetic resonance and gas chromatography-mass spectrometry as ethyl 2-methylacetoacetate. Synthesized ethyl 2-methylacetoacetate also showed allelopathic activity on C. pyrenoidosa and M. aeruginosa. The EC50 of synthesized ethyl 2-methylacetoacetate on C. pyrenoidosa and M. aeruginosa were 0.49 and 0.65 mg/liter, respectively.
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Feng-Min
authors.initials: FM
authors.lastname: Li
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Hu
mesh_terms: D000090:Acetoacetates / Q000737:chemistry / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D002708:Chlorella / Q000187:drug effects*; D056890:Eukaryota / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D046931:Microcystis / Q000187:drug effects*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D006109:Poaceae / Q000737:chemistry*; D013045:Species Specificity
chemical_list: D000090:Acetoacetates; D000900:Anti-Bacterial Agents; D010936:Plant Extracts; C016635:acetoacetic acid