Bio-assay guided isolation of germacranes with anti-protozoan activity from Magnolia sororum

Abstract

In the course of our search for antiprotozoal agents from terrestrial plants, three new germacranes 1, 2 and 3, together with the well known sesquiterpene lactones parthenolide (4) and costunolide (5), were isolated from Magnolia sororum using bioassay- guided fractionation methods. The structures of these new compounds were elucidated by 1D and 2D NMR spectroscopic analysis. Compound 5 exhibited activity (IC50= 9.4 μM) in vitro against the Leishmania mexicana parasite. Additionally, all compounds were also evaluated against Trypanosoma cruzi and Monkey Vero cells without showing much activity.