The allelopathy and allelopathic mechanism of phenolic acids on toxic Microcystis aeruginosa

Cyanobacterial contamination of water has been a serious problem in recent years. Thus, the effective control of undesired cyanobacteria has become an urgent issue. We studied therefore the effects of rho-coumaric acid and vanillic acid on toxic Microcystis aeruginosa and the allelopathic mechanisms. The results showed that the growth of toxic M. aeruginosa was significantly inhibited by rho-coumaric acid and vanillic acid, with an EC50 of 0.26 +/- 0.07 and 0.34 +/- 0.05 mmol L-1, respectively. Our data also demonstrated that both rho-coumaric acid and vanillic acid triggered the generation of superoxide anion radicals (O-2 (aEuro cent a')). The O-2 (aEuro cent a') might induce a lipid peroxidation which may change cell membrane penetrability, thereby leading to the eventual death of M. aeruginosa. Our current studies further provide evidence that some phenolic acids such as rho-coumaric acid and vanillic acid may be a potential effective solution for aquatic management.