title: Structure-mutagenicity relationship of kaurenoic acid from Xylopia sericeae (Annonaceae).
abstract: Kaurane diterpenes are considered important compounds in the development of new highly effective anticancer chemotherapeutic agents. Genotoxic effects of anticancer drugs in non-tumour cells are of special significance due to the possibility that they induce secondary tumours in cancer patients. In this context, we evaluated the genotoxic and mutagenic potential of the natural diterpenoid kaurenoic acid (KA), i.e. (-)-kaur-16-en-19-oic acid, isolated from Xylopia sericeae St. Hill, using several standard in vitro and in vivo protocols (comet, chromosomal aberration, micronucleus and Saccharomyces cerevisiae assays). Also, an analysis of structure-activity relationships was performed with two natural diterpenoid compounds, 14-hydroxy-kaurane (1) and xylopic acid (2), isolated from X. sericeae, and three semi-synthetic derivatives of KA (3-5). In addition, considering the importance of the exocyclic double bond (C16) moiety as an active pharmacophore of KA cytotoxicity, we also evaluated the hydrogenated derivative of KA, (-)-kauran-19-oic acid (KAH), to determine the role of the exocyclic bond (C16) in the genotoxic activity of KA. In summary, the present study shows that KA is genotoxic and mutagenic in human peripheral blood leukocytes (PBLs), yeast (S. cerevisiae) and mice (bone marrow, liver and kidney) probably due to the generation of DNA double-strand breaks (DSB) and/or inhibition of topoisomerase I. Unlike KA, compounds 1-5 and KAH are completely devoid of genotoxic and mutagenic effects under the experimental conditions used in this study, suggesting that the exocyclic double bond (C16) moiety may be the active pharmacophore of the genetic toxicity of KA.
authors.affiliation: Departamento de Fisiologia e Farmacologia, Universidade Federal do Ceará (UFC), CEP: 60430-270, Fortaleza, CE, Brazil.
authors.forename: B C
authors.initials: BC
authors.lastname: Cavalcanti
authors.forename: J R O
authors.initials: JR
authors.lastname: Ferreira
authors.forename: D J
authors.initials: DJ
authors.lastname: Moura
authors.forename: R M
authors.initials: RM
authors.lastname: Rosa
authors.forename: G V
authors.initials: GV
authors.lastname: Furtado
authors.forename: R R
authors.initials: RR
authors.lastname: Burbano
authors.forename: E R
authors.initials: ER
authors.lastname: Silveira
authors.forename: M A S
authors.initials: MA
authors.lastname: Lima
authors.forename: C A G
authors.initials: CA
authors.lastname: Camara
authors.forename: J
authors.initials: J
authors.lastname: Saffi
authors.forename: J A P
authors.initials: JA
authors.lastname: Henriques
authors.forename: V S N
authors.initials: VS
authors.lastname: Rao
authors.forename: L V
authors.initials: LV
authors.lastname: Costa-Lotufo
authors.forename: M O
authors.initials: MO
authors.lastname: Moraes
authors.forename: C
authors.initials: C
authors.lastname: Pessoa
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004224:Diterpenes / Q000737:chemistry* / Q000633:toxicity*; D006801:Humans; D008297:Male; D051379:Mice; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D010936:Plant Extracts / Q000633:toxicity*; D013329:Structure-Activity Relationship
chemical_list: D004224:Diterpenes; D009153:Mutagens; D010936:Plant Extracts; C051436:kaurenoic acid