Investigation Of Chemical Constituents Of Two Alga-derived Endophytic Fungi,Aspergillus Versicolor EN-298 And Penicillium Crustosum EN-311

More than thirty different kinds of algae were collected from Yantai coastline of Shandong Province and then almost thirty diverse fungal strains were isolated from these algae.Sebsequently we screened the alternative strains by TLC and HPLC.As might be expected,two strains were found which had rich metabolites as well as perfect resolution,namely EN-311 and EN-298.The two fungi were cultivated in the 18×1L Erlenmeyer flasks each containing 300 ml PDB medium for 30 days,respectively.After that the culture broth was separated from the mycelia by filtration and extracted with EtOAc,while the mycelia were extracted with a mixture of 80% acetone and 20% water.The combined extracts were subjected to a variety of methods to obtain compounds,including column chromatography,preparative thin layer chromatography and so on.Finally,30 compounds were yielded with persistent effort.Adopting such spectral analysis as 1H-NMR,13C-NMR,MS,UV,IR,we determined all structures of purified compounds including many different types of compounds like six polyketids(AV1-AV6),three norditerpenes(AV7-AV9),eight meroterpenes(PC1-PC8).Among these compounds,there were three new meroterpenes(PC1、PC2、PC3).Last but not least,several biological activity assays were conducted in order to evaluate activites of a part of isolated compounds including brine shrimp lethality and antibacterial activity.Among all the isolated compounds,some meroterpenes produced by EN-311 exhibited significant brine shrimp lethality.In particular,compound PC1 and PC2 showed significant activity with the value of LD50 1.98 and 1.56 μg/ml,respectively.