A new C-glycosyl xanthone isolated from Davallia solida Sandrine Rancon a , Annie Chaboud a, *, Nicole Darbour a , Gilles Comte b , Denis Barron b , Jean Raynaud a , Pierre Cabalion c a Laboratory of Pharmacognosy, Faculty of Pharmacy, 8 Avenue Rockefeller, 69373, Lyon, Cedex 08, France b Natural Products Laboratory, Claude Bernard University of Lyon, 43 Boulevard du 11 novembre 1918, 69622, Villeurbanne, Cedex, France c ORSTOM, UR 4G, De´partement Sante´, 213 rue Lafayette, 75010, Paris, France Received 5 November 1998; received in revised form 21 January 1999; accepted 17 March 1999 Abstract A new xanthone glycoside has been isolated together with mangiferin from Davallia solida. The structures were elucidated by chemical and spectral means as 2-C-b-D-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone (mangiferin, 1) and 2-C-b-D- xylopyranosyl-1,3,6,7-tetrahydroxyxanthone (2). # 1999 Elsevier Science Ltd. All rights reserved. Keywords: Davallia solida; Davalliaceae; Xanthone; 2-C-b-D-xylopyranosyl-1,3,6,7-tetrahydroxyxanthone 1. Introduction Davallia solida (Forst.) Swartz is a fern widely dis- tributed in the West Pacific islands and used in folk medicine for ciguatera treatment (in New Caledonia, Vanuatu) as well as analgesic and purgative (in other Pacific islands) (Bourdy, Cabalion, Amade & Laurent, 1992). Only one study has shown the presence of man- giferin (1) in this fern on the basis of paper chroma- tography results (Richardson, 1983). In the present paper, we confirm the presence of (1) by spectroscopic methods and describe the isolation and identification of a new C-xylosyl-xanthone (2). 2. Results and discussion Air-dried rhizomes were sequentially extracted with solvents of increasing polarities. The evaporated methanolic and methanol-water extracts were taken up in water and partitioned against chloroform and n- butanol. From the latter extract, a precipitate was obtained, which was then purified by preparative TLC leading to mangiferin (1). The supernatant, submitted to a combination of CC led to the isolation of 2-C-b- D-xylopyranosyl-1,3,6,7-tetrahydroxyxanthone (2). UV spectra in methanol and classic reagents for com- pounds 1 and 2 were characteristic for a xanthone with free hydroxyl groups at positions C-1 and C-3 and with an ortho-dihydroxylation pattern (Hostettmann & Hostettmann, 1989; Lins Mesquita, De Barros Correˆce, Gottlieb & Taveira Magahhades, 1968). The molecular formulae C 19 H 18 O 11 and C 18 H 16 O 10 , for 1 and 2 respectively, were deduced from FABMS, 1 H and 13 C NMR data. FABMS, 1 H NMR, UV data and chromatographic behaviour of 1 were similar to those of reference mangiferin. The FABMS spectra of 2 showed quasi-molecular ion peaks at m/z 415 [M+Na] + , 393 [M+H] + and m/z 427 [M+Cl]  , 391[MH]  in positive and negative mode respectively, in accordance with a tetrahydroxy- C-pentosylxanthone. The 13 C NMR spectrum of 2 showed 18 carbon atom signals. The presence of a glycosyl part was indi- cated by five peaks between 70–80 ppm. In the 1 H NMR spectrum, this sugar moiety showed signals in the 3–4.5 ppm range. The 2D COSY experiment clearly demonstrated the glycosidic chaining and the 2D HSQC map indicated that all sugar carbon atoms Phytochemistry 52 (1999) 1677–1679 0031-9422/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0031-9422(99)00190-9 * Corresponding author.