Methylenedioxy bridge-forming cytochrome P450 involved in the biosynthesis of isoquinoline alkaloids. Converts (S)-cheilanthifoline to (S)-stylopine, (S)-scoulerine to (S)-nandinine and (S)-tetrahydrocolumbamine to (S)-canadine, but only the ring A (2,3-position) of the substrates is converted. Catalyzes an oxidative reaction that does not incorporate oxygen into the product. (S)-cheilanthifoline + O2 + reduced [NADPH--hemoprotein reductase] = (S)-stylopine + H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] (S)-tetrahydrocolumbamine + O2 + reduced [NADPH--hemoprotein reductase] = (S)-canadine + H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] (S)-scoulerine + O2 + reduced [NADPH--hemoprotein reductase] = (S)-nandinine + H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] Alkaloid biosynthesis. Expressed in roots and at lower levels in stems and leaves. Up-regulated by methyl jasmonate treatment. Belongs to the cytochrome P450 family.