Component of the monoterpenoid indole alkaloids (MIAs, e.g. echitovenine, tabersonine, lochnericine, 19-hydroxytabersonine and horhammericine) biosynthetic pathway; MIAs are used in cancer treatment and other medical applications (PubMed:31009114). Cytochrome P450 catalyzing the conversion of (-)-tabersonine to 19-hydroxytabersonine, of lochnericine to horhammericine and of (-)-vincadifformine to (-)-minovincinine (PubMed:31009114, PubMed:21454651). (-)-tabersonine + O2 + reduced [NADPH--hemoprotein reductase] = (-)-(R)-19-hydroxytabersonine + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] lochnericine + O2 + reduced [NADPH--hemoprotein reductase] = H(+) + H2O + horhammericine + oxidized [NADPH--hemoprotein reductase] (-)-vincadifformine + O2 + reduced [NADPH--hemoprotein reductase] = (-)-minovincinine + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Alkaloid biosynthesis. Confined to roots. Belongs to the cytochrome P450 family.