title: Two new antiprotozoal 5-methylcoumarins from Vernonia brachycalyx.
abstract: Two new isomeric 5-methylcoumarins, 2'-epicycloisobrachycoumarinone epoxide (1) and cycloisobrachycoumarinone epoxide (2), have been isolated from the roots of Vernonia brachycalyx by means of bioactivity-guided fractionation. The structures were elucidated by MS and NMR spectroscopic methods. Compounds 1 and 2 showed in vitro activity against Leishmania major promastigotes and against Plasmodium falciparum schizonts and demonstrated an inhibition on the proliferation of human lymphocytes, which was significantly weaker than the antiparasitic effects.
authors.affiliation: Phytochemistry Department, National Museums of Kenya, Nairobi, Kenya.
authors.forename: H A
authors.initials: HA
authors.lastname: Oketch-Rabah
authors.forename: E
authors.initials: E
authors.lastname: Lemmich
authors.forename: S F
authors.initials: SF
authors.lastname: Dossaji
authors.forename: T G
authors.initials: TG
authors.lastname: Theander
authors.forename: C E
authors.initials: CE
authors.lastname: Olsen
authors.forename: C
authors.initials: C
authors.lastname: Cornett
authors.forename: A
authors.initials: A
authors.lastname: Kharazmi
authors.forename: S B
authors.initials: SB
authors.lastname: Christensen
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000302:isolation & purification / Q000494:pharmacology; D000981:Antiprotozoal Agents / Q000302:isolation & purification* / Q000494:pharmacology; D003374:Coumarins / Q000302:isolation & purification* / Q000494:pharmacology; D005663:Furans / Q000302:isolation & purification* / Q000494:pharmacology; D018320:Leishmania major / Q000187:drug effects; D008213:Lymphocyte Activation / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D018517:Plant Roots / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry*; D010963:Plasmodium falciparum / Q000187:drug effects
chemical_list: C106390:2'-epicycloisobrachycoumarinone epoxide; D000962:Antimalarials; D000981:Antiprotozoal Agents; D003374:Coumarins; D005663:Furans; C106391:cycloisobrachycoumarinone epoxide