Isolation and structure determination of algicidal compounds from Ulva fasciata

Biosci Biotechnol Biochem. 2005 Nov;69(11):2186-92. doi: 10.1271/bbb.69.2186.


Thirty-seven species of seaweeds including 10 Chlorophyta, 13 Phaeophyta, and 14 Rhodophyta collected from the coast of Nagasaki Prefecture, Japan, were screened for algicidal activity against the red-tide phytoplankton Heterosigma akashiwo. The green alga Ulva fasciata (Ulvaceae, Chlorophyta) showed the strongest algicidal activity among the seaweeds tested. Bioassay-guided fractionation of the methanol extract of U. fasciata led to isolation of three algicidal compounds whose structures were determined to be hexadeca-4,7,10,13-tetraenoic acid (HDTA), octadeca-6,9,12,15-tetraenoic acid (ODTA), and alpha-linolenic acid on the basis of spectroscopic information. These polyunsaturated fatty acids (PUFAs) showed potent algicidal activity against H. akashiwo (LC(50) 1.35 microg/ml, 0.83 microg/ml, and 1.13 microg/ml for HDTA, ODTA, and alpha-linolenic acid, respectively), and the result demonstrated the potential of these PUFAs for practical harmful algal bloom control.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chlorophyta / chemistry
  • Fatty Acids, Unsaturated / isolation & purification*
  • Fatty Acids, Unsaturated / pharmacology*
  • Phytoplankton / drug effects*
  • Seaweed / chemistry
  • Ulva / chemistry*
  • alpha-Linolenic Acid / isolation & purification
  • alpha-Linolenic Acid / pharmacology


  • Fatty Acids, Unsaturated
  • hexadecatetraenoic acid
  • alpha-Linolenic Acid
  • parinaric acid