title: Euphoportlandols A and B, tetracylic diterpene polyesters from Euphorbia portlandica and their anti-MDR effects in cancer cells.
abstract: Two new tetracyclic diterpene polyesters, euphoportlandols A (1) and B (2), have been isolated along with 12 known tetracyclic triterpenes from an acetone extract of Euphorbia portlandica. Their structures were established as 5alpha,11alpha,14alpha,17-tetraacetoxy-3beta-benzoyloxy-6beta,15beta-dihydroxy-9-oxoseget-8(12)-ene (1) and 5alpha,11alpha,14alpha,17-tetraacetoxy-3beta-benzoyloxy-6beta,15beta-dihydroxy-9-oxosegetane (2), respectively, by spectroscopic data interpretation. Compounds 1 and 2 were evaluated for their ability to inhibit multidrug resistance in cancer cells. Both compounds were found to be inhibitors of P-glycoprotein activity.
authors.affiliation: CECF, Faculdade de Farmacia da Universidade de Lisboa, Avenida das Forças Armadas, 1600-083 Lisboa, Portugal.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Madureira
authors.forename: Nora
authors.initials: N
authors.lastname: Gyémant
authors.forename: José R
authors.initials: JR
authors.lastname: Ascenso
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Abreu
authors.forename: Joseph
authors.initials: J
authors.lastname: Molnar
authors.forename: Maria-José U
authors.initials: MJ
authors.lastname: Ferreira
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000187:drug effects*; D000818:Animals; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D028481:Euphorbia / Q000737:chemistry*; D051379:Mice; D008968:Molecular Conformation; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D011174:Portugal; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014700:Verapamil / Q000494:pharmacology
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004224:Diterpenes; D011091:Polyesters; D014315:Triterpenes; C512095:euphoportlandol A; C512096:euphoportlandol B; D014700:Verapamil