3beta-hydroxycostunolide + oxidized [NADPH--hemoprotein reductase] + H2O + H(+) => (+)-costunolide + reduced [NADPH--hemoprotein reductase] + O2
3beta-hydroxycostunolide + oxidized [nadph--hemoprotein reductase] + h2o + h(+) => (+)-costunolide + reduced [nadph--hemoprotein reductase] + o2