Cytotoxic clerodane diterpenoids from Casearia obliqua.
A crude bioactive EtOH extract of the twigs of Casearia obliqua afforded two new clerodane diterpenes, caseobliquins A (1) and B (2). Additionally, bioactivity-directed fractionation on a bioactive hexane extract of the leaves from this species led to the isolation of the known clerodane diterpenes rel-6beta-hydroxyzuelanin-2beta-benzoate and rel-2alpha-hydroxyzuelanin-6beta-benzoate (3 and 4) as a mixture and 2beta-hydroxyzuelanin-6beta-cinnamate (5). The structures of the new clerodanes 1 and 2 were established on the basis of their 1D and 2D NMR spectroscopic data, and the new compound 1 and the known substance 5 had their absolute configurations determined by circular dichroism spectroscopy. The cytotoxicity of several of the compounds isolated was evaluated against a small panel of human tumor cell lines.
Institute of Chemistry, Nuclei of Bioassay, Biosynthesis and Ecophysiology of Natural Products (NuBBE), São Paulo State University, UNESP, Araraquara, SP, Brazil, CP 355, CEP 14801-97.
Gerardo Magela
GM
Vieira
Tiago de Oliveira
Tde O
Gonçalves
Luis O
LO
Regasini
Paulo M Pinheiro
PM
Ferreira
Cláudia do O
Cdo O
Pessoa
Letícia V
LV
Costa Lotufo
Roseli Buzanelli
RB
Torres
Nivaldo
N
Boralle
Vanderlan da Silva
Vda S
Bolzani
Alberto José
AJ
Cavalheiro
D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001938:Brazil; D045785:Diterpenes, Clerodane / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*
D000972:Antineoplastic Agents, Phytogenic; D045785:Diterpenes, Clerodane; C545045:caseobliquin A; C545046:caseobliquin B