Involved in the biosynthesis of macrocyclic lathyrane type diterpenoids (also called Euphorbia factors) natural products, including the cyclization route from casbene to jolkinol C, a precursor for ingenol mebutate that is used to treat actinic keratosis, a precancerous skin condition (PubMed:27506796). Catalyzes the hydroxylation of (-)-casbene and 8-hydroxycasbene to produce 4-hydroxycasbene and 4,8-dihydroxycasbene, respectively (PubMed:27506796). (-)-casbene + O2 + reduced [NADPH--hemoprotein reductase] = 4-hydroxycasbene + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] 8-hydroxycasbene + O2 + reduced [NADPH--hemoprotein reductase] = 4,8-dihydroxycasbene + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] 4,8-dihydroxycasbene + O2 + reduced [NADPH--hemoprotein reductase] = 4,5,8-trihydroxycasbene + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Secondary metabolite biosynthesis; terpenoid biosynthesis. Expressed in mature seeds. Belongs to the cytochrome P450 family.