Metabólitos especiais isolados de Ouratea hexasperma (Ochnaceae), Dipladenia martiana (Apocynaceae) e de Caesalpinia peltophoroides (Leguminosae)

Abstract

The chromatographic fractionation of the Ouratea hexasperma (Ochnaceae), Dipladenia martiana (Apocynaceae) and from Caesalpinia peltophoroides Benth. (Leguminosae) extracts led to the isolation of some chemical constituents belonging different classes of special metabolites. From the leaves of Ouratea hexasperma were identified flavone dimer 5-hydroxy-7-methoxyflavone-(4’-O-8”)-5”,4”’-dihydroxy-7”- methoxyflavone (7,7”-dimethyllanaraflavone), 4’,5,7-trihydroxyflavone-(6®8”)-4”’,5”- 7”-trihydroxyflavone (agathisflavone), 4’,5,7-trihydroxyflavone-(6®8”)-4”’,5”- dihydroxy-7”-methoxyflavone (7”-methylagathisflavone), epicatechin and 2”-O-b-Dglucopyranosyl-8-C-b-D-glucopyranosyl luteolin. From the branches of Dipladenia martiana were identified sorbitol, quebrachitol, 3b-O- b-D-glucopyranosylsitosterol, pomolic acid, ursolic acid, oleanolic acid, epicatechin, kaempferol, quercetin, 3-O-b-Dglucopyranosyl kaempferol, 7-O-b-D-glucopyranosyl quercetin and 7-O- b-Dgalactopyranosyl quercetin. The ethanolic extract of the flowers of Caesalpinia peltophoroides afforded the ethyl brevifolin carboxylate, 5-hydroxymethylfurfural, the flavonoid luteolin, gallic acid, ethyl gallate, sitosterol, 3b-O-b-D-glucopyranosylsitosterol and esqualene. The structures were established by IR, MS and NMR spectral data analysis, including 2D NMR experiments of the natural substances and the acetyl and methyl derivatives. Besides the identification of the new biflavonoid, 7,7”-Odimethy-lanaroflavone, the new derivatives, 7,7”-O-dimethyl-5,5”,4”’- triacetyllanaroflavone and 4’,4”’,7,7”-tetra-O-metil-5,5”-diacetil-agathisflavone were also prepared. The analysis of biflavonoids by HPLC was carried out with of leaves Ouratea semiserrata (Ochnaceae) extracts led to identification of the 7”- methylagathisflavone in this specie for the first time. Biological tests were realized: the general toxicity against Artemia salina, antibacterial, antioxidant from Caesalpinia, cytotoxic and the antitumor activities from Ouratea biflavonoids.