Isolation of antialgal compounds from Potamogeton malaianus and algal inhibitory effects of common fatty acids

One active fraction,which mainly contained many kinds of fatty acids,was extracted and isolated from the submerged macrophyte Potamogeton malaianus,then was analyzed by the GC-MS.The EC50,3d fraction on Selenastrum capricornutum was 7.90mg/L.The inhibition of eight fatty acids in the fraction and oleic acid on S.capricornutum confirmed that fatty acids had the allelopathic inhibitory effect and the effect was relevant to the carbon chain and unsaturated linkages,which meant the shorter the carbon chain of the fatty acid,the stronger the algal growth was inhibited,and the more unsaturated linkages in the fatty acid,the stronger the algal growth was inhibited.The combined activity of multi-fatty acids showed synergistic growth inhibition on S.capricornutum.Another fraction,which mainly consisted of sterols,was isolated from the extraction of P.malaianus,but it did not inhibit the growth of S.capricornutum and had no evident influence on the allelopathic inhibition of fatty acids on S.capricornutum.