Short-chain dehydrogenase/reductase; part of the gene cluster that mediates the biosynthesis of chrodrimanin B, a meroterpenoid that acts as a potent blocker of insect GABA-gated chloride channels (PubMed:30417647). The first step of the pathway is the biosynthesis of 6-hydroxymellein by the polyketide synthase cdmE (PubMed:30417647). The prenyltransferase cdmH acts as a 6-hydroxymellein 5-farnesyltransferase and produces the hydrophobic metabolite verruculide C (PubMed:30417647). The FAD-dependent monooxygenase cdmI further converts verruculide C into verruculide B (PubMed:30417647). The terpene cyclase cdmG then produced the pentacyclic molecule 3-hydroxypentacecilide A, the backbone structure of chrodrimanin B, via folding the farnesyl moiety of the substrate into the chair-boat conformation (PubMed:30417647). The short-chain dehydrogenase/reductase cdmF functions as the 3-OH dehydrogenase that oxidizes the C-3 hydroxyl group of 3-hydroxypentacecilide A and produces chrodrimanin C, the dehydrogenated product of 3-hydroxypentacecilide A (PubMed:30417647). The cytochrome P450 monooxygenase cdmJ then accepts both 3-hydroxypentacecilide A and chrodrimanin C and functions as a C-7-beta-hydroxylase to produce respectively chrodrimanin H and chrodrimanin F (PubMed:30417647). The dioxygenase cdmA accepts chrodrimanin H to afford chrodrimanin E, which is further transformed to chrodrimanin A by the dioxygenase cdmD (PubMed:30417647). CdmA can also accept chrodrimanin C as substrate to convert it into verruculide A, which is further converted into chrodrimanin T by cdmD (PubMed:30417647). The last step of the biosynthesis is proposed to be performed by the acetyltransferase cdmC which acetylates chrodrimanin A to yield chrodrimanin B (Probable). The pathway may also lead to the production of additional shunt products, including chrodrimanins T and U (PubMed:30417647). 3-hydroxypentacecilide A + A = AH2 + chrodrimanin C A + chrodrimanin F = AH2 + chrodrimanin H Secondary metabolite biosynthesis; terpenoid biosynthesis. Compounds in the chrodrimanin family such as chrodrimanin A or verruculide A exhibit strong inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) and therefore, they could potentially be developed into drugs for the treatment of type 2 diabetes or obesity (PubMed:26115570). Furthermore, chrodrimanin B, the end product of the pathway involving chrodrimanin A or verruculide A, does not exhibit the PTP1B inhibitory activity, while it functions as a potent blocker of insect GABA-gated chloride channels (PubMed:25902139). Belongs to the short-chain dehydrogenases/reductases (SDR) family.