Estudo fitoquímico do extrato hexânico e dos óleos voláteis Acritopappus Micropappus.

AUTOR(ES)

Vanessa Rodrigues Guedes

DATA DE PUBLICAÇÃO

2004

RESUMO

The present work describes the phytochemical study of the aerial parts (leaves and stems) of Acritopappus micropappus specimens (Asteraceae) collected on Morro da Antena in Saúde (April 2001); on Morro do Cruzeiro in Jacobina (April 2001) and in Morro do Chapéu (August 1999). The Acritopappus micropappus species is endemic from Chapada Diamantina and, until this moment, no phytochemical study has been reported on this species. The aerial parts were submitted to extractions with hexane followed by methanol. From the hexane extract of the specimen collected in Saúde, the following substances were extracted: the campherenol sesquiterpene that was decomposed by photooxidation, leading to the derived 10x-hidroperoxi-campheren-11-ene and 11-hidroperoxi-campheren-9-ene, the yatein lignan; a mixture with b-amirin, a-amirin, lupeol and pseudotaraxasterol triterpernes; and a mixture with the sitosterol and stigmasterol steroids. Volatile oils were obtained from the aerial parts of the three specimens through hydrodestilation. These oils by analyzed with gas chromatography in association with mass spectrometry leading to the identification of 31 constituents, including 6 monoterpenes, 24 sesquiterpenes and the 6-metil-5-hepten-2-one cetone, showing structural variability among the constituents of the three oils. The major components present in the volatile oil obtained from the specimen collected in Jacobina were germacrene D, a-pinene and b-pinene, from the specimen collected in Saúde were a-humulene, caryophyllene and valerianone, and from the specimen collected from Morro do Chapéu were b-acorenol, 1,10-epoxi-caryophyllene, (+)-junenol and 6-metil-5-hepten-2-one. The fractionations of the hexane extracts and the isolation of the substances were accomplished by using chromatography column over silica and sephadex LH 20. The identification of the substances were made using spectrometrics methods, such as RMN of 1H and 13C (including DEPT, COSY, HETCOR, COLOC and NOESY) and the mass spectrometry. The campherenol sesquiterpene and the yatein lignan are rare in nature; they have been reported in few species of plants. The extracts of the species collected in Morro do Chapéu and Jacobina were submitted to bioassays against the fungus Cladosporium sphaerospermum using the bioauthographic method and preliminary biological assays against Staphylococcus aureus and Candida albicans, respectively. But only the hexane extracts were active.

ASSUNTO(S)

yatein óleos voláteis campherenol yateína canferenol asteraceae asteraceae triterpenes acritopappus micropappus quimica organica volatile oils triterpenos acritopappus micropappus

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