Pergamon 0031-9422(95)00103-4 Phytochemistry, Vol. 39,No. 6, pp. 1433-1436, 1995 Copyright© 1995 Elsevier Science Ltd Printedin Great Britain. Allrights reserved 0031-9422/95$9.50 + 0.00 PENTAOXYGENATED XANTHONES FROM BREDEMEYERA FLORIBUNDA EDILBERTO R. SILVEIRA,* MARIA JOSt~ C. FALC.Z.O,ALISIO MENEZES JR, DAVID G. I. KINGSTON~ and THOMAS E. GLASSy" Curso de P6s-Graduaq.~o em Quimica Orgfinica, Laborat6rio de Produtos Naturais, Departamento de Quimica Orgfinica e Inorgfinica, Universidade Federal do Cear~i,Cx, Postal 12.200, Fortaleza, 60.021, Cear~i,Brazil; t Virginia Polytechnic Institute and State University, Department of Chemistry, Blacksburg, VA, 24061, U.S.A. (Received in revised form 4 January 1994) Key Word lndex--Bredemeyera floribunda; Polygalaceae; roots; "raiz-de-cobra'; pentaoxygenated xanthones. Abstract--A chloroform extract of the roots of Bredemeyerafloribunda yielded two new pentaoxygenated xanthones, 1,7-dihydroxy-3,4,8-trimethoxyxanthone and 1,3,7-trihydroxy-4,8-dimethoxyxanthone, and the ethanol extract of the resulting marc yielded 1,3,6-trihydroxy-2,7-dimethoxyxanthone. Structure determination of these pentaoxygenated xanthones was accomplished by spectral analysis, mainly NMR, including normal and inverse detection techniques such as HETCOR and HMBC. Chemical derivatization and comparison to literature data were also used. INTRODUCTION R80 O OR1 I it Bredemeyera floribunda Wild. popularly designated as R70.~ J~ L j__ "raiz-de-cobra" (Portuguese = snake's root), belongs to ~'~/~ O~/~L, ~'¢. the family Polygalaceae. Some species of the Polygala genus, from the same family, have several popular medi- OR 3 cinal uses, particularly as expectorants, and are well OR known to contain polyoxygenated xanthones [1,2]. An alcoholic solution made from roots of B. floribunda is used orally by the peasant people of Cearfi, northeast RI R3 R 4 R 7 Rs Brazil, to treat snakebite, and a concentrated extract 1 H Me Me H Me showed antidote activity against both Bothrops and 2 H H Me H Me Crotalus venoms (W. B. Mors, NPPN-UFRJ, personal 4 H Me Me Me Me communication). Rao and co-workers have shown that S Me Me Me Me Me the ethanol extractives from roots of B. floribunda offer 6 H H Me Me Me protection to gastric lesions induced by ethanol, acetyl- 7 H Me H Me H salicylic acid and histamine [3]. We now report on the $ H H Me Me H phytochemical investigation of the roots of B.floribunda. RESULTS AND DISCUSSION Ground roots of B. floribunda were initially extracted O OH I l l with chloroform to yield a viscous residue, after solvent MeO~ ~ .,,Jl~ /[,, jOMe evaporation, designated BFR-C. The marc obtained after chloroform extraction was extracted with ethanol to yield a resinous residue designated BFR-E. Liquid-liquid HO - u v "OH partitioning and successive column chromatography of BFR-C yielded 1 and 2. Adsorption chromatography of BFR-E yielded 3. Compound 1, the less polar and major constituent, and had very similar ~H and ~3C NMR spectra (Tables 1 and 2, somewhat more polar than 1 and a minor constituent, 2). For both, the aH NMR spectra showed a hydrogen exchangeable with D20 in the far downfield region (613.01 and 13.03, respectively) characteristic of a hy- *Author to whom correspondence should be addressed, droxyl chelated to a carbonyl group. Both showed two 1433