Involved in the biosynthesis of germacrene-derived sesquiterpene lactones (PubMed:30468448). Component of the parthenolide biosynthetic pathway; parthenolide and conjugates are promising anti-cancer drugs highly active against colon cancer cells (PubMed:30468448). Catalyzes the conversion of costunolide and parthenolide to 3-beta-hydroxycostunolide and 3-beta-hydroxyparthenolide, respectively (PubMed:24704560). (+)-costunolide + O2 + reduced [NADPH--hemoprotein reductase] = 3beta-hydroxycostunolide + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] O2 + parthenolide + reduced [NADPH--hemoprotein reductase] = 3beta-hydroxyparthenolide + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Secondary metabolite biosynthesis; terpenoid biosynthesis. Accumulates progressively during ovary development. Belongs to the cytochrome P450 family.