Preparation And Antipathogen Activities Of Extracts From Algae

The object of this research was to get some natural active substances from algae.The activities of algae on platn virus, plant pathogenic fungus, bacteria were screened.The anti-TMV activities in vitro were determined with ethanol extracts from 8 algae. The results indicated that ethanol extracts from 3 algae had more than 60% inhibiting rate on TMV. Ethanol extracts which inhibiting rates were more than 60% had been extracted by other organic solvent and their inhibiting rates on TMV had been determined. It was shown that the most of anti-TMV substance from Sargassum graminifolium and Ishige okamurai were in petroleum ether extracts and ethyl acetate extracts, fewness was in water extracts. But a majority of anti-TMV substance from Sargassum fusiforme was in water extracts. They were petroleum ether extracts from Ishige okamurai (91%), ethyl acetate extracts from Ishige okamurai (92.31%) and water extracts from Sargassum fusiforme (98.2%) . Petroleum ether extracts from Ishige okamurai and ethyl acetate extracts from Ishige okamurai could not distinctly inhibit multiplication of TMV in the discs of tobacco leaves. The inhibiting rates were 87.69% and 91.54% by spraying petroleum ether extracts from Ishige okamurai and ethyl acetate extracts from Ishige okamurai on Nicotiana glutinosa. The activity of peroxidase (POD) and Polyphenoloxidase (PPO) could be increased by spraying petroleum ether extracts from Ishige okamurai on N. tobacum cv K326. But petroleum ether extracts from Ishige okamurai could not protect tobacco against TMV. The chemical character of petroleum ether extracts from Ishige okamurai was detected by chemical preliminary pretest, paper chromatogram and thin layer chromatogram. It was a sort of phenolic compounds which could inhibit TMV in vitro.The inhibiting effects of the ethanol extracts from the 8 algae on hypha growth of Rhizoctonia solani, Gloeosporium musarum , Alternaria brassicae , Fusarium oxysporum f.sp., Botryosphaeria dothidea , Penicilium expansum , Phytophthoracapsici and Botrytis cinerea were determined. The inhibiting rates of ethanol extracts from Ulva pertusa on Alternaria brassicae is higher than 40%. The inhibiting rates of ethanol extracts of Enteromorpha sp. on Botrytis cinerea, ethanol extracts of Gracilaria verrucosa on Rhizoctonia solani and Botrytis cinerea, ethanol extracts of Hypnea sp. on Botrytis cinerea were also higher than 40%. The inhibiting effects of the ethanol extracts from the 6 algae on conidium germination of Colltotrichum higginsianum, Botryosphaeria dothidea, Curvularia lunata were determined. The ethanol extracts of Gracilaria verrucosa , Hypnea sp., Grateloupia filicina showed more than 70% inhibiting rates on conidium germination of all three-genus fungus. The ethanol extracts of Sargassum fusiforme showed more than 90% inhibiting rate on conidium germination of Botryosphaeria dothidea. The ethanol extracts had inhibiting effects on conidium germination and growth of hypha . The order of inhibiting rate from high to low was the red alga, the green alga, and the brown algae.The ethanol extracts from the 7 algae were tested for antibacterial activities. The result showed that the ethanol extracts from Gracilaria verrucosa, Hypnea sp., Grateloupia filicina had strong and universal inhibiting effects. It was shown that the most of antibacterial substance from Hypnea sp. were in petroleum ether extracts and ethyl acetate extracts. The inhibiting effects of G+ and G- were equal.