Talarolactones A-G, α-Pyrone Dimers with Anti-inflammatory Activities from Talaromyces adpressus , and Their Biosynthetic Pathways.

Talarolactones A-G ( 1 - 7 ), seven novel α-pyrone adducts with unprecedented scaffolds, together with two pairs of α-pyrone monomers [(±)- 8 and (±)- 9 )] were isolated from Talaromyces adpressus . Compounds 1 - 7 are highly modified α-pyrone dimers with a 4,7,7,8-tetrasubstitued 5,6,7,8-tetrahydro-2 H -chromen-2-one. Compounds 5 and 6 possessed a significant NO production inhibitory effect, with IC 50 values of 2.3 ± 0.1 and 3.7 ± 0.3 μM, respectively. Plausible biosynthetic pathways were proposed and supported by the results of heterologous expression experiments.