title: New derivatives of silybin and 2,3-dehydrosilybin and their cytotoxic and P-glycoprotein modulatory activity.
abstract: Large series of O-alkyl derivatives (methyl and benzyl) of silybin and 2,3-dehydrosilybin was prepared. Selective alkylation of the silybin molecule was systematically investigated. For the first time we present here, for example, preparation of 19-nor-2,3-dehydrosilybin. All prepared silybin/2,3-dehydrosilybin derivatives were tested for cytotoxicity on a panel of drugs sensitive against multidrug resistant cell lines and the ability to inhibit P-glycoprotein mediated efflux activity. We have identified effective and relatively non-cytotoxic inhibitors of P-gp derived from 2,3-dehydrosilybin. Some of them were more effective inhibitors at concentrations lower than a standard P-gp efflux inhibitor cyclosporin A. Another group of 2,3-dehydrosilybin derivatives also had better inhibitory effects on P-gp efflux but a cytotoxicity comparable with that of parent 2,3-dehydrosilybin. Structural requirements for improving inhibitory activity and reducing toxicity of 2,3-dehydrosilybin were established. Effect of E-ring substitution as well as an influence of the substituent size at the C-7-OH position of A-ring on P-gp-inhibitory activity was evaluated for the first time in this study.
authors.affiliation: Department of Paediatrics, Faculty of Medicine, Palacký University and University Hospital in Olomouc, Puskinova 6, CZ-775 20, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Dzubák
authors.forename: Marián
authors.initials: M
authors.lastname: Hajdúch
authors.forename: Radek
authors.initials: R
authors.lastname: Gazák
authors.forename: Alena
authors.initials: A
authors.lastname: Svobodová
authors.forename: Jitka
authors.initials: J
authors.lastname: Psotová
authors.forename: Daniela
authors.initials: D
authors.lastname: Walterová
authors.forename: Petr
authors.initials: P
authors.lastname: Sedmera
authors.forename: Vladimír
authors.initials: V
authors.lastname: Kren
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors*; D000478:Alkylation; D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D015394:Molecular Structure; D010084:Oxidation-Reduction; D000077385:Silybin; D012838:Silymarin / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D012838:Silymarin; D000077385:Silybin