Cytochrome P450 that catalyzes an intramolecular para-para' C-C phenol coupling of 4'-O-methylnorbelladine in alkaloids biosynthesis, including haemanthamine- and crinamine-type alkaloids, promising anticancer agents. Catalyzes the formation of (10bR,4aS)-noroxomaritidine and (10bS,4aR)-noroxomaritidine from 4'-O-methylnorbelladine. 4'-O-methylnorbelladine + O2 + reduced [NADPH--hemoprotein reductase] = (10bR,4aS)-noroxomaritidine + H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] 4'-O-methylnorbelladine + O2 + reduced [NADPH--hemoprotein reductase] = (10bS,4aR)-noroxomaritidine + H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] Alkaloid biosynthesis. Alkaloid biosynthesis. Mostly expressed in stems, and, to a lower extent, in bulbs, roots, leaves and flowers. Belongs to the cytochrome P450 family.