FAD-dependent monooxygenase; part of the gene cluster that mediates the biosynthesis of xenovulene A, an unusual meroterpenoid that has potent inhibitory effects on the human gamma-aminobutyrate A (GABAA) benzodiazepine receptor (PubMed:29773797). The first step of xenovulene A biosynthesis is the biosynthesis of 3-methylorcinaldehyde performed by the non-reducing polyketide synthase aspks1 (PubMed:17912413, PubMed:29773797, PubMed:20552126). The salicylate hydroxylase asL1 then catalyzes the oxidative dearomatization of 3-methylorcinaldehyde to yield a dearomatized hydroxycyclohexadione (PubMed:29773797). The 2-oxoglutarate-dependent dioxygenase asL3 further catalyzes the oxidative ring expansion to provide the first tropolone metabolite (PubMed:29773797). The cytochrome P450 monooxygenase asR2 allows the synthesis of tropolone hemiacetal (PubMed:29773797). In parallel, a previously unrecognised class of terpene cyclase, asR6, produces alpha-humulene from farnesylpyrophosphate (FPP) (PubMed:29773797). The putative Diels-Alderase asR5 probably catalyzes the formation of the tropolone-humulene skeleton by linking humulene and the polyketide moiety (PubMed:29773797). Oxidative-ring contractions catalyzed by asL4 and asL6 then processively remove carbon atoms from the polyketide to yield xenovulene A (PubMed:29773797). Binds 1 FAD per subunit. Secondary metabolite biosynthesis; terpenoid biosynthesis. Expression is significantly up-regulated under xenovulene A producing condition. Severely reduces, but does not abolish xenovulene A biosynthesis. Xenovulene A is a natural product exhibiting little structural resemblance with classical benzodiazepines yet is able to displace high-affinity ligand binding to the benzodiazepine site of the gamma-aminobutyrate A (GABAA) receptor and could be potentially used as an anti-depressant with reduced addictive properties. Belongs to the aromatic-ring hydroxylase family.