A new lateral root growth inhibitor from the sponge-derived fungus Aspergillus sp. LS45

Two new gamma-lactones, aspergilactones A (1) and B (2), were discovered along with two known compounds, annularin A (3) and pericoterpenoid A (4), from a culture of the sponge-associated fungus Aspergillus sp. LS45. The planar structures of 1-4 were characterized using comprehensive spectroscopic methods and comparison with literature data. The absolute configurations of 1 and 2 were determined by comparison of electronic circular dichroism (ECD) spectroscopic and optical rotation data with those of known analogues as well as calculated ECD analysis. Compounds 1-4 were tested in a variety of bioassays, and both 1 and 4 exhibited significant inhibition against the lateral root growth of Arabidopsis thaliana Columbia-0 at a concentration of 100 mu M. In addition, the in vitro cytotoxic activities of 1-4 against six human cancer cell lines CCRF-CEM, K562, BGC823, AGS, HCT-116 and MDA-MB-231 were evaluated. Compound 4 showed moderate inhibitory effects on CCRF-CEM and K562 cancer cell lines with IC50 values of 13.8 +/- 1.6 and 12.9 +/- 2.5 mu M, respectively. However, compounds 1-4 did not show any notable AChE inhibitory activity in vitro.