Screening of Biologically Active Compounds in Microalgae

Abstract

As part of the investigation on useful constituents in microalgae, we searched for biologically active compounds in the water-soluble and the fat-soluble fractions of twenty five species and strains of microalgae by means of the antimicrobial activity test and the inhibition test of development of fertilized echinoderm eggs. We found eleven and eight active species by the former and latter test, respectively, and five species to have both activities. The activity existed exclusively in the fat-soluble fractions. For example, a marine cyanophyte Oscillatoria sp.-2, a freshwater diatom Cyclotella sp., and a marine dinoflagellate Goniodoma pseudogoniaulax showed strong inhibition against the fungus Mortierella ramannianus. In particular, the fat soluble fraction of G. pseudogoniaulax inhibited the growth at a concentration of 0.1 mg/ml/. The fraction also had a strong inhibitory effect on the fertilized eggs of the sea urchin Hemicentrotus pulcherrius, stopping the first cleavage at a concentration of as low as 1 μg/ml. © 1988, The Japanese Society of Fisheries Science. All rights reserved.