NADH-dependent flavin oxidoreductase; part of the gene cluster that mediates the biosynthesis of ilicicolin H, a 4-hydroxy-2-pyridonealkaloid that has potent and broad antifungal activities by inhibiting the mitochondrial respiration chain (PubMed:31216742). The biosynthesis of ilicicolin H starts with formation of the tetramic acid by the hybrid PKS-NRPS synthetase iliA with the partnering trans-enoyl reductase iliB since iliA lacks a designated enoylreductase (ER) domain. The cytochrome P450 monooxygenase iliC then catalyzes the ring expansion of the tetramate to the acyclic 2-pyridone. The pericyclase iliD further converts the acyclic 2-pyridone into 8-epi-ilicicolin H. 8-epi-ilicicolin H might then spontaneously convert to ilicicolin H since ilicicolin H is produced in the absence of the epimerase iliE, in contrast to what was observed for the Talaromyces variabilis ilicolin H biosynthetic pathway (PubMed:31216742) (Probable). Belongs to the NADH:flavin oxidoreductase/NADH oxidase family.