Contribuição ao conhecimento químico de plantas do nordeste do Brasil: Aspidosperma ulei Markgr.

Abstract

Aspidosperma ulei Markgr. popularly known as pitiá or piquiá, is a tree of a rough and gray trunk bark. This work reports the phytochemical analysis of the leaves, and the re-investigation of the trunk and roots of an A. ulei specimen collected at the locality of Garapa- Acarape Country – Ceará State. The ethanol extracts of all parts were obtained. Acid/base extraction was performed with the extracts from the trunk and root heartwoods and root bark, in order to obtain the alkaloids fraction. For the leaves and trunk bark small portions of the ethanol extract were submitted to conventional chromatography over silica gel followed by semipreparative HPLC to afford the triterpene ursolic acid, an inositol derivative the methyl-chiro-inositol, and the alkaloids β-yohimbine, yohimbine, 3,4,5,6-tetradehydro-β-yohimbine, 19,20-dehydro-α-yohimbine and 19(E)-hunteracine. From the alkaloidal fractions of the trunk and the root heartwood, were obtained, by semi preparative HPLC, the alkaloids 20(E)-17-nor-subincanadine E, reported for the first time for the species and also an natural product, and the 12-hydroxy-N-acetyl-21(N)-dehydro-plumeran-18-oic acid, on unknown indole alkaloid. From the alkaloidal fraction of the root bark, after semipreparative HPLC, were obtained the indole alkaloids uleine, 20-epi-dasycarpidone, 20-epi-N-nordasycarpidone, N-noruleine, olivacine and the booneine lactone. Ursolic acid and 20(E)-17-nor-subincanadine E were assayed as citotoxic and showed significative results against four tumour cell lines. The identification and characterization of all compounds were realized by means of spectroscopic techniques such as IR, MS and uni and bidimensional NMR, including pulse sequences such as HSQC, NOESY, COSY and HMBC, after comparison to the literature data.