Studies On Secondary Metabolites Of Two Marine-Derived Fungal Strains And Their Antifungal Activities Against Plant Pathogens

Fungal diseases were one of the most important causes for crop damage,which caused nearly several ten billion dollars in direct financial loss.It was considered to be an effective way for controlling the fungal infective diseases by use of chemical pesticides.However,the large use of pesticide made the destruction of ecological environment and the harm of human body health,due to its own strong poisonousness and un-degradation.Thus,discovery of new-type alternative with high-efficiency and environment friendly characteristics was hopeful to substitute chemical pesticides.Marine-derived fungi lived in unique environment for a long time,including high salinity,high pressure,low oxygen,low temperature and so on,which may promote them to possess metabolic pathways and yield novel structures with various bioactivties.Therefore,it is an important way to exploit new-type substitutes with high-efficiency and environment friendly characteristics from the antifungal molecules against plant pathogenic fungi from marine-derived fungi.Herein we investigated the fermentation broth of potato liquid culture medium from Penicillium sclerotiorum A6 and Mucor nidicola AEF15 by ways of chromatography and bioactivity-guided isolation.After performance of extraction,separation and preparation,totally 40 compounds were afforded.The isolated compounds were identified by approaches of spectral analysis.As a result,20 compounds were attined from fungus Penicillium sclerotiorum A6,including 18 azaphilones(1-18),1 terpenoid(19)and 1 fatty acid(20),of which 1-3 and 14 were new compounds,1-3 and 14 were azaphilone molecules.On the other hand,a total of 20 compounds were identified from the secondary metabolites of Mucor nidicola AEF15,including 6 anthranones(21-26),6 benzene derivatives(27-32),2 steroids(33-34),and 7 other structural types of compounds(35-40).It was noted that 21-23 were dianthrone.Some of the isolated compounds above were tested for their antifungal activity against a panel of plant pathogens.The results showed that compounds 20 and 21 displayed obvious inhibitory activity,especially compound 21 showed strong inhibitory activity against Colletotrichum acutatum HNMRC 178 at 100 μg/disc with an inhibition ring diameter of 30 mm,while the carbendazim as positive control appear an inhibition ring diameter of 30 mm at100μg/disc.