ABSTRACT
Objective:To screen for the bioactive marine organisms and to study the active constituents from them.Methods:Bioactivities of marine organisms extracts were screened by Pyricularia oryzae bioassay method and the constituents were isolated and identified by a combination of multi chromatography and spectral analysis.Results:Twenty ethanolic extracts and 5 aqueous extracts of the tested marine organisms showed activities causing morphological abnormality of P.oryzae mycelia.Fifty six compounds were obtained and identified from Sargassum carpophyllum,Ishige okamurai and Natarchus leachii freeri ,among which 28 compounds showed activities against P.oryzae and exhibited cytotoxicities on various cultured tumor cell lines,eight compounds showed inhibition effects on Fonsecaea pedrosoi in vitro .Conclusion:The screening data and bioactivity evaluation suggest the P.oryzae bioassay is suitable for preliminary screening of bioactive agents from marine organisms.