Guy Balansard

Laurent Debrauwer

Lucienne Nze-Ekekang

Marie-Louise Rondi

Maroufath Lamidi

Robert Faure

Évelyne Ollivier

Comptes Rendus Chimie

http://france.elsevier.com/direct/CRAS2C/C. R. Chimie 9 (2006) 1309–1313Preliminary communication / CommunicationFlavonoid glycosides from Sclerochiton vogeliiMaroufath Lamidi a, Marie-Louise Rondi b, Robert Faure d, Laurent Debrauwer e,Lucienne Nze-Ekekang a, Guy Balansard c, Évelyne Ollivier c,*a IPHAMETRA (CENAREST), BP 842, Libreville, GabonbFMSS, BP 6087, Libreville, Gabonc Laboratoire de pharmacognosie, faculté de pharmacie, université de la Méditerranée,27, boulevard Jean-Moulin, 13385 Marseille cedex 05, FrancedUMR 6178, université Paul-Cezanne, avenue Escadrille-Normandie-Niemen, 13397 Marseille cedex 20, FranceeUMR 1089 xénobiotiques, Inra–ENVT, 180, chemin du Tournefeuille, BP 3, 31931 Toulouse cedex 09, FranceReceived 16 September 2005; accepted after revision 5 May 2006Available online 14 June 2006AbstractTwo new flavonoid glycosides, 7-O-{α-L-rhamnopyranosyl-(1 → 6)-[β-D-glucopyranosyl-(1 → 2)]-β-D-glucopyranosyl} luteo-lin 1 and 7-O-β-D-apiofuranosyl (1 → 2)-β-D-xylopyranosyl luteolin 2, with the known flavone glycoside, 7-O-α-L-rhamnopyra-nosyl-(1 → 6)-β-D-glucopyranosyl luteolin 3 were isolated from Sclerochiton vogelii (Acanthaceae). Their structures were deter-mined on the basis of spectroscopic analyses (UV, IR, ESI-MS, 1D and 2D NMR). To cite this article: M. Lamidi et al., C. R.Chimie 9 (2006).© 2006 Académie des sciences. Published by Elsevier SAS. All rights reserved.RésuméDeux nouveaux hétérosides flavoniques, 7-O-{α-L-rhamnopyranosyl-(1 → 6)-[β-D-glucopyranosyl-(1 → 2)]-β-D-glucopyrano-syl} lutéoline 1 et 7-O-β-D-apiofuranosyl (1 → 2)-β-D-xylopyranosyl lutéoline 2, avec un hétéroside flavonique connu, 7-O-β-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranosyl lutéoline 3, ont été isolés de Sclerochiton vogelii (Acanthaceae). Les structures ontété déterminées sur la base d’analyses spectroscopiques (UV, IR, ESI-MS, 1D et 2 D RMN). Pour citer cet article : M. Lamidi etal., C. R. Chimie 9 (2006).© 2006 Académie des sciences. Published by Elsevier SAS. All rights reserved.Keywords: Sclerochiton vogelii; Acanthaceae; Flavonoids; Luteolin glycosideMots-clés : Sclerochiton vogelii ; Acanthaceae ; Flavonoides ; Hétéroside de la lutéoline1. IntroductionSclerochiton vogelii (Nees) T. Anderson (Acantha-ceae), is a herbaceous traditional medicinal plant usedin Gabon by healers. The decoction from aerial parts is* Corresponding author.E-mail address: Evelyne.Ollivier@pharmacie.univ-mrs.fr(É. Ollivier).1631-0748/$ - see front matter © 2006 Académie des sciences. Published bdoi:10.1016/j.crci.2006.05.004used for the treatment of hypertension and anemia.Until now, the chemistry of the plant has not been in-vestigated. In this study, the isolation and structureelucidation of two new flavones: 7-O-{α-L-rhamnopyr-anosyl-(1 → 6)-[β-D-glucopyranosyl-(1 → 2)]-β-D-glu-copyranosyl} luteolin 1 and 7-O-β-D-apiofuranosyl(1 → 2)-β-D-xylopyranosyl luteolin 2 and one knownflavone glycoside: 7-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranosyl luteolin 3 are reported.y Elsevier SAS. All rights reserved.M. Lamidi et al. / C. R. Chimie 9 (2006) 1309–13131310The structure of the compound 1 was elucidatedusing one- and two-dimensional NMR (COSY, HMQCand HMBC) and mass spectrometry, while the structureof 2 and 3 were determined by MS, 1H NMR, 13CNMR and COSY experiments. The spectral data forcompound 3 were in good agreement with those pre-viously reported in the literature [1]. This last com-pound is described for the first time in this plant.2. Experimental2.1. General experimental proceduresOptical rotations were measured on a Perkin Elmer,341 OROT 589 nm Polarimeter.UV spectra were recorded on a SpectrophotometerUV/Vis Beckman DU 520.IR spectra were performed on a Nicolet 205 XBFTIR spectrometer.Melting points were determined on a Buchi Meltingpoint B 540 apparatus.Mass spectra were obtained on a Finnigan LCQquadrupole ion trap instrument fitted with an electro-spray ionization source operated in the negative ionmode. Sample solutions (0.5 mg l–1 in CH3OH/H2O(50:50) were analyzed by infusion at a flow rate of3 μl min–1. Hydrogen/deuterium exchange experimentswere carried out by using CH3OD/D2O (50:50) as thesolvent system instead of the non deuterated one. Theelectrospray needle was set at –4.5 kV. The heatedtransfer capillary was maintained at 200 °C. Other op-erating parameters were adjusted for each sample inorder to optimize the signal and obtain the maximalstructural information from the ion of interest. All spec-tra were acquired under automatic gain control (AGC)conditions using helium as buffering and collision gasfor MS/MS experiments.1H NMR, 13C NMR and 2D NMR spectra were de-termined on a Bruker Avance DRX-500 spectrometeroperating at 500.13 MHz (1H NMR) and 125.75 MHz(13C NMR) in CD3OD (compounds 2 and 3) andDMSO-d6/TFAA (9:1) (compound 1). TMS was usedas internal standard in 1H and 13C measurements. Stan-dard Bruker pulse sequences were used for 2D experi-ments. Copies of the original spectra are obtainablefrom the correspondence author.2.2. Plant materialA sample of the herbaceous S. vogelii was collectedin Libreville, Gabon in April 1996. A voucher speci-men (SV-4-1996, HNG 53) identified by H. Bourobou,botanist (National Herbarium of Gabon at the Instituteof Traditional Pharmacopoeia and Medicine (IPHAME-TRA) is kept in the Department of Pharmacognosy, Fa-culty of Pharmacy, Marseilles, France and in the her-barium of the IPHAMETRA Institute (Libreville,Gabon).2.3. Extraction and isolationThe decoction was prepared by heating the driedplant (1 kg) at 100 °C in H2O during 15 min. After de-cantation and filtration, the H2O layer was freeze dried.The aqueous extract (5 g) was partitioned on polyamidewith a gradient of acetone, ethanol, MeOH in H2O: H2O(1.5 l), MeOH 20% (1.5 l), MeOH 40% (1.5 l), MeOH50% (1.5 l), MeOH 60% (1.5 l), MeOH 80% (1.5 l),MeOH (2 l), ethanol (1 l), acetone/H2O (80:20) (2 l).According to the differences in composition moni-tored by TLC 12 fractions were obtained (F1–F12).F6 was subjected to silica gel chromatography, elut-ing under isocratic conditions with EtOAc/iso-PrOH/H2O (65:25:5). Five fractions were obtained(A–E).Fractions B and D were subjected individually to gelfiltration on Sephadex LH-20 and elution with acetone.Flavone 3 (14 mg), a pure yellow compound, wasobtained from fraction B (130 mg).Fraction D (50 mg) was chromatographed andyielded the pure flavone 2 (28 mg).F9 (1 g) was applied to a silica gel column, elutingunder isocratic conditions with EtOAc/iso-PrOH(65:25). Seven fractions were obtained (F–L).Fraction G (300 mg) was partitioned on polyamidewith MeOH–H2O (gradient from 30% of MeOH to100% MeOH V/V). According to differences in com-position monitored by TLC, six fractions (G1–G6) wereobtained. Fraction G2 (61 mg) was fractionated on aSephadex LH-20 column eluting with acetone, yieldingtwo fractions. One fraction gave flavone 1 (30 mg).2.3.1. 7-O-{α-L-rhamnopyranosyl-(1 → 6)-[β-D-glucopyranosyl-(1 → 2)]-β-D-glucopyranosyl} luteolin(1)Yellow powder; m.p. = 230 °C; [α]20D = –0.56(MeOH, C = 1); UV λ MeOHmax nm 254, 351; IR γKBrmax cm−1 3294 (OH), 3089, 2930, 2861, 1640(C=O), 1558, 1369, 1072; for 1H and 13C NMR spectraldata, see Table 1; ESI-MS C33H40O20.Table 11H and 13C NMR spectral data of compound 1 in DMSO-d6/TFAA (9:1). Chemical shifts are given in ppm; multiplicities and coupling constants Jin HzC/H δC δH C/H δC δHGENIN Glc12 164.7 – 1 98.5 5.22d (J = 7.5)3 103.3 6.70s 2 82.7 3.58m4 181.8 – 3 76.5 3.24t (J = 8.8)5 161.2 – 4 69.7 3.19m6 99.8 6.51 (d, J = 1.5) 5 75.5 3.66m7 162.9 – 6 65.9 3.89d (J = 11.1)8 95.1 6.79 (d, J = 1.5) 3.50m9 157.2 –10 105.5 – Glc21′ 121.5 – 1 104.9 4.51d (J = 7.8)2′ 113.8 7.42brs 2 74.7 3.19m3′ 145.7 – 3 77.1 3.18m4′ 149.9 – 4 70.8 3.20m5′ 116.3 6,93 (d, J = 8,0) 5 77.1 3.18m6′ 119.4 7.43 (brd, J = 8.0) 6 60.8 3.56m3.49mRham1 100.4 4.58brs2 70.4 3.70brs3 70.8 3.52m4 72.3 3.19m5 68.4 3.46dq (J = 9.1;6.2)6 17.8 1.09d (J = 6.2)M. Lamidi et al. / C. R. Chimie 9 (2006) 1309–1313 13112.3.2. 7-O-β-D-apiofuranosyl (1 → 2)-β-D-xylopyranosyl luteolin (2)Yellow powder; m.p. = 203 °C; [α]20D = –45(MeOH, C = 1); UV λ MeOHmax nm 254 , 351;1HNMR spectral data (500.13 MHz, CD3OD): aglyconeδ 6.49 (1H, J = 1.5 Hz, H-6), 6.77 (1H, d, J = 1.5 Hz,H-8), 6.94 (1H, d, J = 8.0 Hz, H-6′), 7.41 (1H, brs, H-2′), 7.43 (1H, brd, J = 8.0 Hz, H-6′); xylose δ 3.08 (1H,d, J = 11.0 Hz, H-5A), 3.22 (2H, m, H-2 and H-4), 3.30(1H, m, H-3), 3.70 (1H, m, H-5B), 4.25 (1H, d,J = 7.5 Hz); apiose d 3.63 (2H, m, H-5), 3.79 (1H, d,J = 10.0 Hz, H-4A), 4.01 (1H, d, J = 3.0 Hz, H-2), 4.15(1H, d, J = 10.0 Hz, H-4B), 5.25 (1H, d, J = 3.0 Hz, H-1); 13C NMR spectral data (125.75 MHz, CD3OD):aglycone δ 95.93 (C-8), 100.82 (C-6), 104.10 (C-3),107.06 (C-10), 114.21 (C-2′), 116.87 (C-5′), 120.57(C-6′), 123.27 (C-1′), 147.19 (C-3′), 151.59 (C-4′),158.88 (C-9), 162.93 (C-5), 164.42 (C-7), 166.89 (C-2), 183.97 (C-4); xylose: δ 66.87 (C-5), 70.95 (C-4),78.20 (C-3),78.79 (C-2), 100.87 (C-1); apiose: δ 65.86(C-5), 75.44 (C-4), 77.88 (C-2), 80.68 (C-3), 111.08(C-1); ESI-MS C25H26O14.2.3.3. 7-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranosyl luteolin (3)13C NMR spectral data (125.75 MHz, CD3OD):aglycone δ 95.88 (C-8), 100.48 (C-6), 104.17 (C-3),107.07 (C-10), 114.29 (C-2′), 116.84 (C-5′), 120.55(C-6′), 123.46 (C-1′), 147.08 (C-3′), 151.28 (C-4′),158.88 (C-9), 162.92 (C-5), 164.20 (C-7), 166.83(C-2), 183.97 (C-4); glucose: δ 67.30 (C-6), 70.96(C-4), 74.02 (C-2), 78.62 (C-5), 79.07 (C-3), 100.87(C-1); rhamnose: δ 18.25 (C-6), 70.05 (C-5), 71.17(C-2), 72.21 (C-3), 72.55 (C-4), 100.48 (C-1); ESI-MS: m/z 629 [M–H]– corresponding to the molecularformula C27H34O17.3. ResultsThe extraction was realized from the decoction byrepeated column chromatography yielding three purecompounds.Compound 1 was obtained as yellow powder andgave a yellow orange color by spraying Neu’s reagent(1% diphenylboric ethanolamine complex in MeOH).The ESI MS gave a molecular peak m/z 755 [M–H]–corresponding to the molecular formula C33H40O20.Other important fragments in the spectrum were atm/z 609 [M–146–H]– (loss of a deoxyhexose moiety),m/z 593 [M–162–H]– (loss of a hexose moiety), m/z447 [M–162–146–H]– (loss of a hexose and deoxy-hexose moieties), m/z 285 [M–162–146–162–H]– (lossof two hexoses and one deoxyhexose moieties). TheseFig. 1. Structure of the compound 1.Fig. 2. Structure of flavone glycosides.M. Lamidi et al. / C. R. Chimie 9 (2006) 1309–13131312results indicated the presence of three sugars, withthe inner hexose directly linked to the aglycone andbearing two terminal sugars (a hexose and a deoxy-hexose).The downfield shifts observed for the C-6(99.8 ppm) and C-8 (95.1 ppm) resonances of luteolinsuggested that the sugar chain is linked to C-7 of theaglycone. The HMBC spectrum showed a correlationbetween C-7 of the luteolin and the anomeric protonof the inner glucose confirming that the glucose is di-rectly linked to luteolin at this position. The 13C NMRsignal at δ 82.7 ppm attributed to C-2 of the inner glu-cose suggested a glucosyl-(1 → 2) glucosyl moiety (asin sophorosyl) [1]. The HMBC spectrum exhibited acorrelation between C-2 of the inner glucose and theanomeric proton of the terminal glucose. The HMBCspectrum also showed a correlation between C-6 ofthe inner glucose (δ 65.9 ppm) and the anomeric protonof the terminal rhamnose, in agreement with a rhamno-syl (1 → 6) glucosyl moiety (as in rutinosyl) [1]. Thissugar chain has already been described for a kaempferolglycoside [2,3]. The NMR spectral data are in goodagreement with those previously reported. From theabove spectral evidence, the structure of compound 1was established as 7-O-{α-L-rhamnopyranosyl-(1 → 6)-[β-D-glucopyranosyl-(1 → 2)]-β-D-glucopyranosyl} lu-teolin, a new compound (Fig. 1).Compound 2 gave a yellow orange color with Neu’sreagent. The aglycone was identified as luteolin bycomparison with literature data [1]. Negative ESI massspectrum gave a peak at m/z = 549 [M–H]– correspond-ing to the molecular formula C25H26O14. Other impor-tant fragments were observed at m/z 417 [M–162–H]–and at m/z 285 [M – 162 – 162 – H]–. These resultswere confirmed by 13C NMR spectral data. Downfieldshifts observed for C-6 and C-8 resonances were indi-cative of the C-7 substitution. The presence of thedisaccharide β-D-xylose (2 → 1) apiose linked at theC-7 of the aglycone was deduced by comparison withprevious reported 13C NMR data [4] for such sugarlinkage and confirmed by the analysis of the COSYspectrum.The structure of 2 was elucidated as 7-O-β-D-apio-furanosyl (1 → 2)-β-D-xylopyranosyl luteolin 2. Thecampanoside acetate (in position 3 of apiose) of thestructure 2 was previously reported in Campanula patu-la [5], but flavone 2 is a new compound.All carbon signals of the compound 3 were assignedby comparison with the previously reported 13C NMR[6,7]. The structure of 3 was elucidated as: 7-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranosyl luteolin.This flavone is described for the first time in the plant(Fig. 2).[2][3][4][5][6][7]M. Lamidi et al. / C. R. Chimie 9 (2006) 1309–1313 13134. ConclusionThree flavones are described for the first time in thisplant and two of them are new compounds. This workis a contribution to the knowledge of the chemistry ofS. vogelii.It would be interesting to study if these flavonoidsparticipate to the activity of the plant.References[1] P.K. Agrawal, Studies in organic chemistry, vol. 39, Elsevier,Amsterdam, 1989 (p. 324).K. Cimanga, T. de Bruyne, B. Van Poel, Y. Ma, M. Claeys, L.Pieters, K. Kambu, L. Tona, P. Bakana, D. VandenBerghe, A.J.Vlietinck, Planta Med. 63 (1997) 220.W. Zhe, J. Zhongjian, C. Tzetsin, Y. Chongren, Z. Jun, Acta Bot.Yunnanica 8 (1986) 157.M. Hamburger, M. Gupta, K. Hostetteman, Phytochemistry 24(1985) 2689.L.M. Belenosvskaya, L.P. Marlova, G.I. Kapranova, KhimiyaPrirodnykh Soedinenii 6 (1980) 835.S.D. Petrović, M.S. Gorunović, V. Wray, I. Merfort, Phytochem-istry 50 (1999) 293.J.B. Harborne, The Flavonoids: Advances in research since 1986,Chapman and Hall, London, 1993 (p. 349).

Flavonoid glycosides from <i>Sclerochiton vogelii</i>

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Flavonoid glycosides from <i>Sclerochiton vogelii</i>

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