Component of the seco-iridoid and derivatives monoterpenoid indole alkaloids (MIAs, e.g. secologanin) biosynthesis pathway. Catalyzes the conversion of loganin into secologanin. loganin + O2 + reduced [NADPH--hemoprotein reductase] = H(+) + 2 H2O + oxidized [NADPH--hemoprotein reductase] + secologanin Alkaloid biosynthesis. Expressed in leaves (especially in leaf epidermis), and, to a lower extent, in roots, stems, flower buds and flowers. By jasmonic acid (MeJA). Large increases in loganin accumulation. Belongs to the cytochrome P450 family.