Navegando por Assunto "Terpenos"

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Acesso aberto (Open Access)
Biflavones and triterpenoids isolated from Ouratea castaneifolia (DC.) Engl., Ochnaceae
(2009-12) NASCIMENTO, Luís Adriano Santos do; GUILHON, Giselle Maria Skelding Pinheiro; ARRUDA, Mara Silvia Pinheiro; SANTOS, Lourivaldo da Silva; ARRUDA, Alberto Cardoso; MÜLLER, Adolfo Henrique; SILVA, Milton Nascimento da; RODRIGUES, Silvane Tavares; CARVALHO, Mário Geraldo de
This paper presents the chemical investigation of the leaves and stems of Ouratea castaneifolia (DC.) Engl.. There are no chemical or pharmacological studies with this species. Classic phytochemical investigation of the organic extracts together with high pressure liquid chromatography (HPLC) procedures lead to the identification of seventeen metabolites: seven triterpenes (friedelin, 3β-friedelinol, α-amyrin, β-amyrin, lupeol, germanicol and taraxerol), four steroids (sitosterol, stigmasterol and the glycosides sitosteryl 3-O-β-D-glucopyranoside and stigmasteryl 3-O-β-D-glucopyranoside), one isoflavone (5,7,4’-trimethoxyisoflavone), one flavone (5,4’-dihydroxy-7,3’,5’-trimethoxyflavone) and four biflavones (amenthoflavone, 7,7”- O-dimethylamenthoflavone, heveaflavone and tetramethylamenthoflavone). The structures of the compounds were established by the analysis of 1H, 13C NMR spectra including bidimensional techniques. The classes of the identified metabolites are in agreement with previous studies of the Ouratea genus.
Acesso aberto (Open Access)
Isolation, X-ray crystal structure and theoretical calculations of the new compound 8-Eepicordatin and identification of others terpenes and steroids from the bark and leaves of Croton palanostigma Klotzsch
(2010) BRASIL, Davi do Socorro Barros; MÜLLER, Adolfo Henrique; GUILHON, Giselle Maria Skelding Pinheiro; ALVES, Claudio Nahum; PERIS, Gabriel; LLUSAR, Rosa; MOLINER, Vicent
Phytochemical studies of the bark and leaves of Croton palanostigma Klotzsch (Euphorbiaceae) led to the isolation of a new clerodane diterpene, 8-epicordatin (2), in addition to 12-oxohardwickiic acid methyl ester (3), aparisthman, cordatin (1), ent-trachyloban-18-oic acid, ent-13-epimanoyl oxide, ent-3-oxo-13-epimanoyl oxide, ent-3β-hydroxy-13-epimanoyl oxide, sitosterol, stigmasterol, stigmastan-3-one, 6β-hydroxystigmast-4-en-3-one, 6β-hydroxystigmasta-4,22-dien-3-one, stigmast-4-en-3-one, stigmasta-4,22-dien-3-one, 3-O-acetylaleuritolic acid, 11α-hydroxyurs-12-en-3-one, α-amyrenone, 24-methylenecycloartenone and lupenone. These compounds were isolated using typical phytochemical procedures and the structures were deduced from spectroscopic studies, including 2D NMR experiments. In addition, the crystalline structure of 8-epicordatin (2) was determined by X-ray diffraction. NMR theoretical calculations at the B3PW91/DGDZVP level were used to confirm the assignment of the chemical shifts of the H-7α and H-7β hydrogens of 8-epicordatin.