(S)-Stylopine is an important intermediate in the biosynthesis of benzophe-nanthridine alkaloids, such as sanguinarine. Stylopine biosynthesis involves the sequential formation of two methylenedioxy bridges. Although the methylenedioxy bridge-forming P450 (CYP719) involved in berberine bio-synthesis has been cloned from Coptis japonica[Ikezawa N, Tanaka M,