title: Anti-leukemia activity of semi-synthetic phenolic derivatives from Polygonum limbatum Meisn.
abstract: BACKGROUND
  The present report describes the semi-synthesis of a few O-prenylated phenolic derivatives and their in vitro antitumor activities. These compounds were prepared by modifying two naturally occurring antitumor phenols, 5,7-dihydroxy-3-(1'-hydroxy-1'-phenyl-methyl)-6-methoxy-chroman-4-one (A) and 2',4'-dihydroxy-3',6'-dimethoxychalcone (B), previously isolated from Polygonum limbatum Meisn. (Polygonaceae). The structures were elucidated by spectroscopic means and comparison with published data. The cytotoxicity of compounds was determined by using the resazurin assay in the parental drug-sensitive CCRF-CEM cell line and its multidrug-resistant P-glycoprotein-over-expressing subline, CEM/ADR5000.
  
  
  RESULTS
  We describe in the present paper four new semi-synthetic derivatives of A and B: 5-hydroxy-6-methoxy-7-O-(3'-methylbut-2'-enyl)chroman-4-one (1), trivially named metapchromone, 5-acetoxy-6-methoxy-7-O-[3'-methylbut-2'enyl]chroman-4-one (2), trivially named sargisin, 2'-hydroxy-3',6'-dimethoxy-4'-O-(3″-methylbut-2″-enyl)chalcone (3) trivially named limbachalcone A, and 2'-acetoxy-3',6'-dimethoxy-4'-O-(3″-methylbut-2″-enyl)chalcone (4) trivially named tsedengchalcone. Their preliminary cytotoxic activities have been determined. We also report herein the isolation of 1-methylhydantoin (C) and betulinic acid (D) from Polygonum limbatum for the first time.
  
  
  CONCLUSIONS
  The study clearly suggests that semi-synthesis involving O-prenylation and acetylation of chalcones or other chromanones should be avoided in a search for anticancer drugs. This conclusion should be helpful when selecting substituents for the synthesis of potential anticancer drugs.
authors.affiliation: Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon ; Centro de Analises Proteômicas e Bioquimicas, Pós-Graduação em Ciencias Genomicas e Biotecnologia, Universidade Catolica de Brasilia, Brasilia, DF Brazil ; Dipartimento di Chimica, Laboratorio di Chimica delle Sostanze Organiche Naturali e Centro di Etnobiofarmacia (CISTRE), Università degli Studi di Pavia, Via Taramelli, 12-27100 Pavia, Italy.
authors.forename: Antoine Honoré Lonfouo
authors.initials: AH
authors.lastname: Nkuété
authors.affiliation: Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, University of Mainz, Staudinger Weg 5, 55128 Mainz, Germany ; Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
authors.forename: Victor
authors.initials: V
authors.lastname: Kuete
authors.affiliation: Dipartimento di Chimica, Laboratorio di Chimica delle Sostanze Organiche Naturali e Centro di Etnobiofarmacia (CISTRE), Università degli Studi di Pavia, Via Taramelli, 12-27100 Pavia, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Gozzini
authors.affiliation: Centro de Analises Proteômicas e Bioquimicas, Pós-Graduação em Ciencias Genomicas e Biotecnologia, Universidade Catolica de Brasilia, Brasilia, DF Brazil ; S-Inova Biotech, Universidade Catolica Dom Bosco, Campo Grande, MS, Brazil.
authors.forename: Ludovico
authors.initials: L
authors.lastname: Migliolo
authors.affiliation: Instituto de Química, Universidade de Brasília, Brasilia, DF Brazil.
authors.forename: Aline Lima
authors.initials: AL
authors.lastname: Oliveira
authors.affiliation: Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
authors.forename: Hippolyte K
authors.initials: HK
authors.lastname: Wabo
authors.affiliation: Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
authors.forename: Pierre
authors.initials: P
authors.lastname: Tane
authors.affiliation: Dipartimento di Chimica, Laboratorio di Chimica delle Sostanze Organiche Naturali e Centro di Etnobiofarmacia (CISTRE), Università degli Studi di Pavia, Via Taramelli, 12-27100 Pavia, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vidari
authors.affiliation: Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
authors.forename: Thomas
authors.initials: T
authors.lastname: Efferth
authors.affiliation: Centro de Analises Proteômicas e Bioquimicas, Pós-Graduação em Ciencias Genomicas e Biotecnologia, Universidade Catolica de Brasilia, Brasilia, DF Brazil ; S-Inova Biotech, Universidade Catolica Dom Bosco, Campo Grande, MS, Brazil.
authors.forename: Octávio Luiz
authors.initials: OL
authors.lastname: Franco
keywords: LimbachalconeA; Metapchromone; Phenolic compounds; Sargisin; Tsedengchalcone