Estudo fitoquímico biomonitorado da espécie poiretia bahiana (leguminosae).

by Magalhães, Floricéa

The present work describes the phytochemical study of leaves and stems of Poiretia bahiana (Leguminosae) specimens collected on Morro do Pai Inácio, in Chapada Diamantina, Bahia, on July 1997 and July 1999. Poiretia bahiana is a endemic species from Chapada Diamantina, and to the best of our knowledge no phytochemical study has been reported to this genus. The leaves of the specimens collected in 1997 were extracted with hexane followed by methanol. From the hexane extract were isolated six isoflavones, two rotenones, a mixture of the triterpenes lupeol and amp;#946;-amirin and a mixture of stigmasterol and sitosterol. From the methanolic extract the new 2?,4?,5? trimethoxyisoflavone-7-O-amp;#946;-D-glucopyranoside was isolated, besides of this the proline amino acid and the ciclytol 3-O-metilchiroinositol. From the aerial parts of the specimen collected in 1999, an essential oil was obtained byhydrodistillation, where eleven constituents were identified. Nine of them were monoterpenes and two of them were sesquiterpenes. The major constituent of the essential oil was indentified as the monoterpene thujenone, which was isolated later by chromatography column over silica gel. Chromatographic techniques were used for the fractionation of the extracts and the isolation of the substances. The identification of the substances was accomplished by spectral analysis such as 1H and 13C NMR (including DEPT,HOMOCOSY and HETCOR), mass and IR spectra. The extracts obtained were submitted to the bioassays in order to verify itsantifungal activities using spores of the phytopathogenic fungus Cladosporium sphaerospermum; where both were actives. The substances 7,3?,4?-trimethoxyisoflavone, 7,2?,4?,5?-tetramethoxyisoflavone, rotenone e 12ahydroxyrotenone,isolated from the hexane extract, were responsible for the antifungal activity.