title: Antiplasmodial triterpenoids from Ekebergia capensis.
abstract: From the stem bark of Ekebergia capensis, 10 new triterpenoid compounds, ekeberins A (1), B (2), C1 (3), C2 (4), C3 (5), D1 (6), D2 (7), D3 (8), D4 (9), and D5 (10), were isolated together with 17 known compounds. The structures of these new compounds were elucidated on the basis of the results of spectroscopic analysis, and the absolute configuration of compounds 6-10 were determined by partial synthesis from known compounds and using the Mosher ester method. Several of these compounds were screened in vitro against both chloroquine (CQ)-sensitive and -resistant Plasmodium falciparum isolates and were found to exhibit moderate antiplasmodial activity, with compounds 20 (7-deacetoxy-7-oxogedunin) and 27 (2-hydroxymethyl-2,3,22,23-tetrahydroxy-2,6,10,15,19,23-hexamethyl-6,10,14,18-tetracosatetraene) showing IC50 values of 6 and 7 microM, respectively. Compound 27 at a dose of 500 mg/kg showed moderate parasitemia suppression of 52.9% against P. berghei NK 65 in a mouse model.
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, 52-1, Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Murata
authors.forename: Toshio
authors.initials: T
authors.lastname: Miyase
authors.forename: Francis Wamakima
authors.initials: FW
authors.lastname: Muregi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Naoshima-Ishibashi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Umehara
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Warashina
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kanou
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Mkoji
authors.forename: Mamoru
authors.initials: M
authors.lastname: Terada
authors.forename: Akira
authors.initials: A
authors.lastname: Ishih
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D002738:Chloroquine / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D007630:Kenya; D029582:Meliaceae / Q000737:chemistry*; D051379:Mice; D015394:Molecular Structure; D021261:Parasitic Sensitivity Tests; D024301:Plant Bark / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D010962:Plasmodium berghei / Q000187:drug effects; D010963:Plasmodium falciparum / Q000187:drug effects; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D000962:Antimalarials; D014315:Triterpenes; D002738:Chloroquine