Two New Citrinin Derivatives From the Marine Sponge‐Derived Fungus Aspergillus sp. S4I4‐4
Chao‐Jian Feng, Xin‐Wei Yang, Bing‐Xin Zhao, Shi‐Hai XuABSTRACT
Two new citrinin derivatives, xanone ( 1 ) and aspercitrinin ( 2 ), together with seven known ones ( 3 – 9 ), were isolated from the marine sponge‐derived fungus Aspergillus sp. S4I4‐4. Their structures with absolute configurations were determined by spectroscopic methods (UV, IR, MS, and NMR), x‐ray diffraction analysis and ECD calculation. Compound 1 was the fifth example of citrinin dimer bearing a 5/6/6/6 skeleton with a disclosed pyran ring isolated from natural sources. Notably, compound 1 exhibited potent to moderate cytotoxic activity against eight tumor cell lines, with IC 50 values ranging from 3.43 to 19.71 µM and cisplatin served as the positive control. Compound 1 also demonstrated significant antibacterial activities against Enterococcus faecalis ATCC 29212 with a MIC value of 4 µg/mL and ciprofloxacin served as the positive control.