Neosartoricin is a carbotricyclic metabolite produced by Aspergillus fumigatus and Neosartorya fischeri following activation of their polycyclic polyketide prenyltransferase (pcPTase)-containing silent clusters, reported by Tang and colleagues from University of California Los Angeles USA in 2013. Neosartoricin exhibits T-cell antiproliferative activity with an IC50 of 3 μM, suggesting a possible physiological role as an immunosuppressive agent.