Monooxygenase involved in the biosynthesis of carnosate, a potent antioxidant labdane-related diterpene natural product (By similarity). Catalyzes the oxidation of 11-hydroxyferruginol to produce carnosate (By similarity). Mediates the conversion of miltiradien into miltiradien-20-al (PubMed:27703160). Also involved in the production of pisiferic acid and derivative products from ferruginol (By similarity). 11-hydroxyferruginol + 3 O2 + 3 reduced [NADPH--hemoprotein reductase] = carnosate + 4 H(+) + 4 H2O + 3 oxidized [NADPH--hemoprotein reductase] miltiradiene + 2 O2 + 2 reduced [NADPH--hemoprotein reductase] = 2 H(+) + 3 H2O + miltiradien-20-al + 2 oxidized [NADPH--hemoprotein reductase] ferruginol + 3 O2 + 3 reduced [NADPH--hemoprotein reductase] = 4 H(+) + 4 H2O + 3 oxidized [NADPH--hemoprotein reductase] + pisiferate Secondary metabolite biosynthesis; terpenoid biosynthesis. Mostly expressed in young leaves, particularly in glandular trichomes. Belongs to the cytochrome P450 family.