Dihydrobenzophenanthridine oxidase (DHBP oxidase) is an enzyme. In the IUBMB Enzyme Nomenclature, dihydrobenzophenanthridine oxidase is EC 1.5.3.12.

Dihydrobenzophenanthridine oxidase produces oxidized forms of benzophenanthridine alkaloids:

• In Sanguinaria canadensis (bloodroot), dihydrobenzophenanthridine oxidase produces sanguinarine from dihydrosanguinarine, and chelirubine from dihydrochelirubine.
• In Eschscholzia californica (California poppy), dihydrobenzophenanthridine oxidase produces macarpine from dihydromacarpine.

• Chelirubine, Macarpine and Sanguinarine Biosynthesis
• Ignatov A, Clark WG, Cline SD, Psenak M, Krueger J, Coscia CJ (1996). "Elicitation of dihydrobenzophenanthridine oxidase in Sanguinaria canadensis cell cultures". Phytochemistry. 43 (6): 1141–4. doi:10.1016/S0031-9422(96)00540-7. PMID 8987906.
• Park SU, Yu M, Facchini PJ (2002). "Antisense RNA-mediated suppression of benzophenanthridine alkaloid biosynthesis in transgenic cell cultures of California poppy". Plant Physiol. 128 (2): 696–706. doi:10.1104/pp.010741. PMC 148930. PMID 11842172.
• Rho D, Chauret N, Laberge N, Archambault J (1992). "Growth characteristics of Sanguinaria canadensis L. cell suspensions and immobilized cultures for production of benzophenanthridine alkaloids". Appl. Microbiol. Biotechnol. 36 (5): 611–7. doi:10.1007/BF00183237. PMID 1368065.
• KEGG (Kyoto Encyclopedia of Genes and Genomes) Alkaloid biosynthesis I - Reference pathway