Methylenedioxy bridge-forming cytochrome P450 involved in the biosynthesis of isoquinoline alkaloids. Converts (S)-scoulerine into (R,S)-cheilanthifoline. Catalyzes an oxidative reaction that does not incorporate oxygen into the product. (S)-scoulerine + O2 + reduced [NADPH--hemoprotein reductase] = (S)-cheilanthifoline + H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] Alkaloid biosynthesis. Expressed in roots. Detected in leaves and stems. Up-regulated by methyl jasmonate treatment. Belongs to the cytochrome P450 family.