New Dihydroisocoumarin Root Growth Inhibitors From the Sponge-Derived Fungus Aspergillus sp. NBUF87.

Six new dihydroisocoumarins, aspergimarins A-F (1-6), were discovered together with five known analogs (7-11) from a monoculture of the sponge-derived fungus Aspergillus sp. NBUF87. The structures of these compounds were elucidated through comprehensive spectroscopic methods, and absolute configurations were assigned after X-ray crystallography, use of the modified Mosher's method, and comparison of electronic circular dichroism (ECD) data with literature values for previously reported analogs. Compounds 1-11 were evaluated in a variety of bioassays, and at 100 mu M, both 1 and 5 showed significant inhibitory effects on the lateral root growth of Arabidopsis thaliana Columbia-0 (Col-0). Moreover, at 100 mu M, 5 also possessed notable inhibition against the primary root growth of Col-0. Meanwhile, 1-11 were all found to be inactive in vitro against acetylcholinesterase (AChE) (IC50 > 100 mu M), four different types of human-derived cancer cell lines (IC50 > 50 mu M), as well as methicillin-resistant Staphylococcus aureus and Escherichia coli (MIC > 50 mu g/mL), and Plasmodium falciparum W2 (EC50 > 100 mu g/mL), in phenotypic tests.