Studies On Secondary Metabolites Of Aspergillus Aculeatus ATCC16872 V1.1

With the widely distribution and numerous species, fungi are abundant sources of natural products. As their metabolites which have special biological activities are playing a very important role of exploiting new medicine and protecting agriculture and forestry, researchers have put much more attention on fungi in recent years. While Aspergillus is widely used in the fermentation and food industries, its metabolites have various structures among which there are many bioactive compounds. In order to discover novel compounds with intriguing bioactivities, we studied the fungus, Aspergillus aculeatus ATCC16872 v1.1. The results are obtained as follows:1) Screening the fermentation conditions of A. aculeatus was performed. Eight different media, namely, CYA, CYAS, YES, CY20, YAG, LCMM, GMM and Czapek’s, were examined. The profiles of organic extracts of solid cultures of the fungal strain on small scale at 30 °C were analyzed by use of LC-MS method, it was suggested that the best fermentation conditions were YES and 5 days.2) Organic extracts of the solid agar of the fungus grown on large scale were subjected to column chromatography on silica gel and preparative C18 HPLC to afford seven compounds(1-7). Their structures were determined as four known nordaucane sesquiterpenoids, aculenes A–D(2-4, 6), and two new ones, an ent-daucane-type sesquiterpenoid, asperaculane A(1), and a nordaucane one, asperaculane B(5), along with the known polyketide secalonic acid D(7), through spectroscopic data, including 1D and 2D-NMR spectra, IR, UV, HR-ESIMS, electronic circular dichroism(ECD) data, quantum chemical calculations, as well as the advanced Marfey’s method.3) Compounds(1-6) were evaluated for in vitro cytotoxic activity against two cell lines, human cancer cell lines(HeLa) and one normal hamster cell line(CHO). Unfortunately, none of the compounds showed any cytotoxicity below IC50 values of 50 μM.