Adpressins A-G: Oligophenalenone Dimers from Talaromyces adpressus

Nine new oligophenalenone dimers, adpressins A-G (1-9), together with nine known compounds (10-18), were isolated from the fungus Talaromyces adpressus. Their chemical structures were determined on the basis of spectroscopic and mass spectral analyses. Their relative and absolute configurations were identified by ¹H and ¹³C NMR calculations followed by DP4+ analyses, electronic circular dichroism (ECD) calculations, and ECD spectra comparison with related compounds. Compound 1 is the first example of a duclauxin derivative featuring an unusual 6/6/6/5/6/6/6 ring system, while compounds 6 and 7 contained a novel pyrrolidine ring. Compounds 5, 9, and 18 exhibited moderate inhibition against LPS-induced B lymphocyte proliferation with IC₅₀ values ranging from 1.6 to 8.6 μM. Additionally, compounds 9 and 18 exhibited moderate inhibition against Con A-induced T lymphocyte proliferation with IC₅₀ values of 9.3 and 2.6 μM, respectively.