PHYTOCHEMISTRY Phytochemistry 67 (2006) 504–510 www.elsevier.com/locate/phytochem Oligomeric secoiridoid glucosides from Jasminum abyssinicum q Francesca Romana Gallo a,*, Giovanna Palazzino a, Elena Federici a, Raffaella Iurilli a, Franco Delle Monache b, Kusamba Chifundera c, Corrado Galeffi a a Dipartimento del Farmaco, Istituto Superiore di Sanità, V. le Regina Elena 299, 00161 Rome, Italy CNR, Centro Chimica dei Recettori, Università Cattolica S. Cuore, L.F. Vito 1, 00168 Rome, Italy Institut Supérieur d’Ecologie pour la Conservation de la Nature, Lwiro, P.O. Box 293 Cyangugu, Rwanda b c Received 29 March 2005; received in revised form 28 September 2005 Available online 27 December 2005 Abstract From the root bark of Jasminum abyssinicum (Oleaceae) collected in Congo was isolated tree oligomeric secoiridoid glucosides named craigosides A–C. The three compounds are esters of a cyclopentanoid monoterpene with an iridane skeleton, esterified with three, two and two, respectively, units of oleoside 11-methyl ester. The structures were elucidated by spectroscopic methods and chemical correlations.
2005 Elsevier Ltd. All rights reserved. Keywords: Jasminum abyssinicum; Oleaceae; Root bark; Oligomeric secoiridoid glucosides; Craigoside A; Craigoside B; Craigoside C 1. Introduction Genus Jasminum (Oleaceae) includes beyond 200 species, some of which are used in folk medicine or cultivated to obtain essential oil from the fragrant flowers. The term Jasminum (Oleaceae) was first mentioned in the ‘‘Materia Medica’’ of Dioscoride (I A.D.). The phytochemical studies of the aerial parts of some species, J. sambac [Soland.] (Tanahashi et al., 1988), J. mesnyi Hance (Tanahashi et al., 1989), J. urophyllum Hemsl. (Shen and Hsieh, 1997) and J. nudiflorum Lindl. (Tanahashi et al., 2000), resulted in the isolation of some secoiridoid glucosides, in particular of oligomeric consisting of oleoside units linked to a cyclopentanoid monoterpene named iridane. This study deals with the structure elucidation of three oligomeric secoiridoid glucosides, two trimer and one tetramer, isolated from the root bark of Jasminum abyssinicum R. Br. (= Hochst. ex DC.) and named craigosides A, 1, B, q Presented at FITOMED 2004, 1 Congresso Intersocietà sulle Piante Medicinali, Trieste, Italy, 16–19 September, 2004. * Corresponding author. Tel.: +39 06 49903055; fax: +39 06 49903060. E-mail address: gallo@iss.it (F.R. Gallo). 0031-9422/$ - see front matter
2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.phytochem.2005.11.007 2, and C, 3, as a tribute to L.C. Craig (Craig and Post, 1949) and his apparatus of counter-current distribution (CCD) utilised for our separations. The aerial parts of this plant are used in Traditional Medicine in the South Kivu Province, Congo against endoparasitic worms and for treatment of mumps (Chifundera, 2001). 2. Results and discussion Craigoside A, 1, is an amorphous powder, C61H86O34 (ICR-FTMS, m/z 1385.48602 [M + Na]+), ½a
20 D ¼ 185 (MeOH), kmax 233 nm (log e 4.54). Its 1H and 13C NMR spectra (Tables 1 and 2) showed inter alia a pattern of signals corresponding to oleoside methyl ester, viz., an acetalic methine and an anomeric methine, a vinylic oxymethine, an ethylidene and a carbomethoxy. In agreement with the molecular formula of 1, the signals of some carbons (6, 8, 9, 1 0 , 4 0 and 6 0 ) of this iridoid moiety appeared in triplicate and in particular the methoxy group, d 52.05, 52.03 and 52.00. This accounted for the presence of three oleoside methyl ester units and thus the presence of cyclic esters engaging two carboxylic groups of the same oleoside could 505 F.R. Gallo et al. / Phytochemistry 67 (2006) 504–510 OGl O O=C H COOMe 10" 9" H2C O CH2 H2C HO OH CH2 OH 8" 7" H2C O MeOOC H C=O 1" 4" O=C O 11 7 5" H2C O O 3" 2" H COOMe MeOOC H O=C C=O H COOMe 4 CH3 5 6" O 3 6 CH3 O 10 9 8 1 OGl OGl O O OGl OGl Craigoside A (1) Craigoside B (2) OGl O O=C H HO O MeOOC H H2C H2C CH2 COOMe O OH C=O Craigoside C (3) CH3 O OGl be ruled out. The LR HETCOR observed in 1 between the a-b unsaturated carboxyl group, d 168.6, and the methoxy group, d 3.72, accounted for the methyl ester in position 11 of the iridoid and therefore the other carboxyl group, (C-7, d 173.1), was engaged in the linkage with the non-iridoidic moiety. The 10 minor 13C signals of craigoside A due to this last part of the molecule corresponded to a cyclopentanoid monoterpene, endowed with three oxymethylene groups, d 68.4, 65.1 and 61.2, an oxymethine, d 80.0, and a methyl group, d 19.7. By alkaline hydrolysis of 1 and subsequent methylation with diazomethane, dimethyl oleoside, 4, and tetraol iridane 5, C10H20O4 (ICR-FTMS, m/z 227.12552 [M + Na]+), 26 ½a
D ¼ þ2:4 (MeOH), were obtained. This last substance appeared different from the two known tetraols 6 and 7 obtained by saponification of sambacosides A, E and F of J. sambac (Tanahashi et al., 1988) and of jasurosides C and D of J. urophyllum (Shen and Hsieh, 1997), respectively. In particular, the cyclic methylene of 5, instead of at d 37.7 and 37.0, as in 6 and 7, respectively, resonated at higher chemical shift (d 43.2), as in the known triol 8 (d 43.7) obtained from nudiflosides A–C of J. nudiflorum (Tanahashi et al., 2000) and having an hydroxy group in position 400 instead of 500 . 11 7 MeOOC H COOMe 4 3 6 5 O 10 9 8 1 O HO 1' 2' O 3' OH 4' OH 5' 6' OH Dimethyl oleoside (4) The HETCOR and selective 1H-1H decoupling of the tetra-acetyl derivative of 5, 9, gave full account of its structure and relative stereochemistry. Thus the irradiation of H-400 of the acetoxymethine (d 5.12, quintet, J = 6.0, 3.0 and 3.0) made the two signals of the adjacent methylene, d 1.52, dq, J = 13.5, 10.5 and 6.0, Ha-500 , and d 1.83, m, J = 13.5, 6.8 and 3.0, Hb-500 , into two dd with the loss of the couplings of J = 6.0 and 3.0, respectively. Moreover, 506 F.R. Gallo et al. / Phytochemistry 67 (2006) 504–510 Table 1 1 H NMR spectroscopic data of compounds 1, 2, 3 and 5 in CD3OD Position 1 1 2 3 5 5.97, 5.94, 7.54, 7.53, 4.10, bs bs s s dd (11.0; 4.8) 5.96, 5.94, 7.54, 7.55, 4.16, s s s s dd (11.0; 4.8) 6a 2.72, dd (13.0; 4.8) 6b 2.49, dd (13.0; 11.0) 8 6.10, bq (6.8) 10 1.77, 1.75, 1.73, 3.72, 4.82, 2.76, 2.70, 2.51, 2.47, 6.12, 6.11, 1.76, dd (13.0; dd (13.0; dd (13.0; dd (13.0; bq (6.8) bq (6.8) d (6.9) 3 MeO 10 2 0 -5 0 60 a 60 b 100 200 300 400 500 a 500 b 600 700 800 900 1000 A d d d s d (6.8) (6.8) (6.8) 5 5.95, s 7.55, s 4.29, dd (11.0; 4.8) 4.19, dd (11.0; 4.8) 2.76, dd (13.0; 4.8) 4.8) 4.8) 11.0) 11.0) 2.52, 2.48, 6.11, 6.10, 1.77, 1.75, dd (13.0; 11.0) dd (13.0;11.0) bq (6.8) bq (6.8) d (6.8) d (6.8) 3.74, s 4.83, d (7.6) 3.73, s 4.83, d (7.6) A A A 3.66, m 3.94, m 1.93, m 1.69, m 1.91, m 5.11, m 1.52, ddd (12.6; 6.7; 3.6) 1.95, m 1.09, d (6.5) 4.05 m 1.89 m 4.12 m 3.66, m 3.99, m 1.94, m 1.68, m 1.90, m 5.11, m 1.53, ddd (13.0; 6.7; 2.5) 1.86, m 1.10, d (6.6) 4.06, m 1.83, m 3.66 m 3.66 m 3.99 m 1.93, m 1.69, m 1.90, m 4.10, m 1.52, ddd (12.5; 6.7; 3.5) 1.88, m 1.07, d (6.6) 4.05, m 1.86, m 3.63 m 3.59 m 3.68 m 4.11 m (7.6) 1.97, 1.51, 1.75, 4.08, 1.48, 1.70, 1.03, 3.70, 1.70, 3.63, 3.61, 3.59, m (6.9; 6.9) m m (5.1) q (5.1; 5.1; 5.1) m (11.9; 6.9; 5.1) m (11.9; 5.1) d (6.9) m m m m m In the range 3.3–3.5. the irradiation in the range of d 4.0–4.2 corresponding to the three acetoxymethylenic groups made the signal of H800 (d 2.11, m) into a doublet with J = 6.3 and the signal of H-200 (d 1.63, m) into a perfect triplet, J = 9.0. The dihedral angle of H-200 both with H-100 and H-300 consistent with this last coupling was about 140 (trans relationship with both) and it corresponded to a position of C-200 out of the plane of the other four carbons of the cyclopentanoid ring, thus allowing a quasi equatorial allocation of the substituents in 200 and 300 . This ring conformation in 9 was in agreement with the coupling constants J = 3.0 Hz between H-300 and H-400 and between H-400 and Hb-500 corresponding to the dihedral angle of about 115 (trans relationship for both). In tetraol 5, the signal d 4.08 of H-400 was a quartet, due to the identical coupling constant, J = 5.1, with H-300 , Ha500 and Hb-500 . The cis relationship between HO-400 and Hb-500 was further confirmed by the downfield shift of the latter, d 1.70, respect to Ha-500 , d 1.48, owing to the anisotropic effect of the former. In order to establish the absolute configuration of tetraol 5, according the MosherÕs method through esterification of the secondary alcoholic function with (S)-MTPA and (R)-MTPA (Ohtani et al., 1991), tetraacyl derivatives 10 and 11 were prepared, respectively. The results of Dd (1H NMR) (dS  dR) showed, in line with the models of Fig. 1, the b configuration of the hydroxyl group in 400 . The structure 5 was thus unambiguously established for the tetraol iridane of craigoside A. 9" 5 4 RO 10" H2C R 7" H2C H C 1" 1 R R 8" 2 3" 2" 6 CH2 R 4" 5 " 3 6" R B= (S)-MTPA radical C= (R)-MTPA radical R1 5 6 7 8 9 10 11 -- Me -- Me – Me --Me --Me --Me --Me R2 R3 – OH H H – OH H -- OH – OH H – OAc H – OB H – OC H R4 R5 R6 H H H H Ac B C OH OH OH H OAc OB OC OH OH OH OH OAc OB OC The three 11-methyl oleoside units on tetraol 5 in craigoside A, 1, were assigned in positions 400 , 700 and 900 on the F.R. Gallo et al. / Phytochemistry 67 (2006) 504–510 Table 2 13 C NMR spectroscopic data of compounds 1, 2,3 and 5 in CD3OD Position 1 2 3 5 1 3 4 5 6 7 8 9 10 11 MeO 10 20 30 40 50 60 100 200 300 400 500 600 700 800 900 1000 95.2 155.1 109.4; 109.3 31.8; 31.7 41.4; 41.3; 41.2 173.1 125.0; 124.9; 124.8 130.9; 130.7;130.6 13.8 168.6 52.05; 52.03; 52.00 100.9; 100.8; 100.7 74.7 78.4; 78.3 71.5; 71.4; 71.3 77.9 62.9; 62.8; 62.7 37.0 49.5 49.9 80.0 41.3 19.7 68.4 43.5 65.1 61.2 95.3; 95.2 155.5 109.8; 109.7 31.9; 31.8 41.6; 41.4 173.0; 172.9 125.1; 125.0 130.6; 130.5 13.9;13.8 168.8; 168.7 52.1; 52.0 100.9; 100.8 74.9; 74.8 78.6; 78.5 71.6 78.0 62.8; 62.7 37.3 49.8 49.7 80.3 41.8 20.0 68.7 46.8 62.7 62.0 95.2; 95.1 155.3 109.5 32.0 41.4; 41.3 173.4; 173.3 125.0 130.8; 130.7 13.9 168.8; 168.7 52.2; 52.1 100.9; 100.8 74.9; 74.8 78.5 71.6; 71.5 78.0 62.6 35.7 49.6 52.6 74.4 43.6 20.7 67.7 42.8 61.6 64.2 35.1 51.9 52.6 75.5 43.2 20.9 65.8 46.3 62.7 61.9 CH (3'') (5'') HC 2 downfield C (4'') MeO upfield CH (3'') (5'') 2HC upfield downfield C (4'') Ph Ph 507 and C-700 , d 68.7, respect to the corresponding values of the tetraol, d 75.5 and 65.8, respectively, showed unambiguously the positions of the two iridoid moieties in the molecule of craigoside B. Respect to craigoside A, 1, the absence of an iridoid unit at C-900 in craigoside B, 2, resulted in the upfield shift of C-900 itself from d 65.1 to 62.7 and the downfield shift of C-800 from d 43.5 to 46.8. Craigoside C, 3, is an amorphous powder, C44H64O24 (ICR-FTMS, m/z 999.37081 [M + Na]+), ½a
20 D ¼ 160 (MeOH), kmax 236 nm (log e 4.26 ). Its 1H and 13C NMR data are reported in Tables 1 and 2, respectively. The alkaline hydrolysis of this trimer, isomer of 2, and the subsequent methylation with diazomethane likewise gave tetraol 5 and dimethyl oleoside, 4. The downfield shifts observed in 3 only for C-700 , d 67.7, and C-1000 , d 64.2, respect to the corresponding values of 5, d 65.8 and 61.9, besides the b upfield shifts for C-200 and C-800 in the former, gave account of the positions 700 and 1000 for the two oleoside 11-methyl ester units. The CD curve of craigoside A, having the same configuration at C-800 as molihuaside E from J. sambac (Zhang et al., 1995), showed an additional band at 247 nm besides the band at 228 nm. In summary, the oligomeric secoiridoid glucosides, new respect to the previously described ones occurring in the aerial parts of Jasminum genus plants, have been isolated from the root bark of J. abyssinicum from Congo. The three oligomeric, craigoside A, tetramer, and craigosides B and C, trimer, have the same cyclopentanoid monoterpene, which is a tetraol iridane, 5, esterified by oleoside 11-methyl ester units. OMe H H (R) (S) 3. Experimental CF3 CF3 3.1. General MeO (3'') HC Ph (5'') O (5'') H2C (R) 4'' H O CF3 Ph (3'') HC OMe O H2C (S) 4'' H CF3 O Fig. 1. Configurational correlation models for the (R)-MTPA derivatives and the (S)-MTPA derivatives proposed by Mosher. basis of the a downfield effects (and the b upfield effects) on the 13C resonances respect to the corresponding ones of the tetraol. Thus the chemical shifts of C-400 , C-700 and C-900 in 5, d 75.5, 65.8 and 62.7, respectively, moved to d 80.0, 68.4 and 65.1 in craigoside A. Craigoside B, 2, is an amorphous powder, C44H64O24 20 (ICR-FTMS, m/z 999.36655 [M + Na]+), ½a
D ¼ 170 1 13 (MeOH), kmax 236 nm (log e 4.29). Its H and C NMR spectra (Tables 1 and 2) showed the signals typical of 11methyl oleoside, the most of them in duplicate. By alkaline hydrolysis and subsequent methylation, the aforementioned tetraol 5, and dimethyl oleoside, 4, were obtained. The downfield shifts observed in 2 only for C-400 , d 80.3, A Craig-Post apparatus, 200 stages, 10:10 ml, upper and lower phase, for the CCD. 1H NMR, 300 MHz, 13C NMR, 75 MHz, TMS as internal standard, chemical shifts (d) in ppm, coupling constants (J) in Hz, Varian Gemini 300. ICR-FTMS, high resolution, APEX II Bruker; ESI-MS, Thermo Finnigan, and FAB-MS, VG 7070 EQ-HF. CD, Jasco 710. 3.2. Plant material Root barks of J. abyssinicum R. Br. were collected in March 1999 near Bukavu (South Kivu Province, Congo). The plant material was identified in the Institut Supérieur dÕEcologie pour la Conservation de la Nature, Lwiro (Cyangugu, Rwanda), where a voucher specimen (Mubeza, B 346) is deposited. 3.3. Extraction and isolation Air-dried root barks (310 g) were extracted three times with MeOH. The residue from the evaporation of the sol- 508 F.R. Gallo et al. / Phytochemistry 67 (2006) 504–510 vent (32.6 g) was dissolved in water (350 ml) and extracted with EtOAc (2 · 300 ml). The aqueous phase evaporated to dryness under vacuum gave as residue 26.5 g. Six grams of this was submitted to CCD with the biphase system H2O:EtOAc:n-PrOH discontinuously changing the ratio from 10:9:1 to 10:7:3. The separations were monitored by TLC, silica gel F254, solvent n-BuOH:H2O:HOAc = 4:5:1 (upper phase); detection by fluorescence quenching and/or by spray reagent anisaldehyde: H2SO4:HOAc:EtOH = 0.5:0.5:0.1:9. Three of the nine collected fractions, J6, 514 mg, J7, 441 mg, and J6/7, 138 mg, were submitted to CCD on recycling with the solvent system H2O:EtOAc:n-PrOH = 10:7:3 and three pure compounds, craigoside C, 3, 203 mg, craigoside B, 2, 170 mg, and craigoside A, 1, 366 mg, were obtained. 3.4. Craigoside A (1) 20 Amorphous powder, ½a
D ¼ 185 (MeOH, c 0.5), UV (MeOH), kmax nm (log e): 233 (4.54); CD (MeOH), k nm ([H]): 211 (8.1 · 107), 228 (12.7 · 107), 247 (8.8 · 107). Molecular formula C61H86O34, ICR-FTMS m/z: 1385.48602 [M + Na]+, calcd 1385.48927; ESI-MS m/z: 1386.6, 16 [M + Na]+, 1224.3, 100 [M + Na  162]+, 1062.4, 7 [M + Na  162 · 2]+, 982.4, 67 [M + Na  an iridoid  H2O]+, 819.3, 32 [M + Na  an iridoid  H2O  162]+. 1H and 13C NMR data in Tables 1 and 2, respectively. 3.5. Craigoside B (2) Amorphous powder, ½a
20 D ¼ 170 (MeOH, c 0.4), UV (MeOH), kmax nm (log e): 236 (4.29); CD (MeOH), k nm ([H]): 233 (7.0 · 107). Molecular formula C44H64O24, ICR-FTMS m/z: 999.36655 [M + Na]+, calcd 999.36797; ESI-MS m/z: 1000.3, 41 [M + Na]+, 837.3, 55 [M + Na  162]+, 595.3, 100 [M + Na  an iridoid  H2O]+. 1 H and 13C NMR data in Tables 1 and 2, respectively. 3.6. Craigoside C (3) 20 Amorphous powder, ½a
D ¼ 160 (MeOH, c 0.4), UV (MeOH), kmax nm (log e): 236 (4.26); CD (MeOH), k nm ([H]): 232 (5.7 · 107). Molecular formula C44H64O24, ICR-FTMS m/z: 999.37081 [M + Na]+, calcd 999.36797; ESI-MS m/z: 999.5, 34 [M + Na]+, 837.3, 100 [M + Na  162]+, 595.3, 15 [M + Na  an iridoid  H2O]+. 1H and 13 C NMR data in Tables 1 and 2, respectively. 3.7. Acetylation of craigosides A–C Each substance (50 mg) was acetylated with pyridine and Ac2O (each, 0.5 ml). After evaporation of the reagents under vacuum, the compound was purified by CC (silica gel, solvents cyclohexane:EtOAc = 2:8) to give the corresponding pure peracetate. 3.7.1. Craigoside A tredeca-acetate 24 Crystals from cyclohexane, mp 87–89 C, ½a
D ¼ 153 1 (CHCl3, c 0.4). H NMR (CDCl3) d: 7.46 (3H, s, H-3 · 3); 6.01, 5.99 (3H, bq, J = 6.7, H-8 · 3); 5.72 (3H, bs, H-1 · 3); 5.28 (3H, t, J = 9.3, H-3 0 · 3); 5.13 (3H, t, J = 9.3, H4 0 · 3); 5.12 (3H, dd, 9.3, 7.8, H-2 0 · 3); 5.11 (1H, m, H-400 ); 5.06 (3H, d, J = 7.8, H-1 0 · 3); 4.33 (3H, dd, J = 12.3, 3.2, Ha-6 0 · 3); 4.10 (3H, dd, J = 12.3, 1.5, Hb-6 0 · 3); 3.96 (3H, dd, J = 11.0, 4.8, H-5 · 3); 3.78 (3H, m, J = 9.3, 3.2, 1.5, H-5 0 · 3); 3.71 (9H, s, MeO · 3); 2.66 (3H, dd, J = 13.0, 4.8, Ha-6 · 3); 2.42 (3H, dd, J = 13.0, 11.0, Hb-6 · 3); 2.11 (1H, m, H-800 ); 2.08, 2.04 (39H, s, CH3CO · 13); 1.94 (1H, m, Hb-500 ); 1.86 (1H, m, H-300 ); 1.75 (9H, d, J = 6.9, H310 · 3); 1.65 (1H, m, H-200 ); 1.51 (1H, m, Ha-500 ); 1.05 (3H, d, J = 6.3, H3-600 ). 13C NMR d: 170.9, 170.4, 170.0 (C7 · 3); 169.3, 169.2 (CH3CO · 13); 166.6 (C-11 · 3); 152.9 (C-3 · 3); 128.5, 128.2 (C-9 · 3); 124.7, 124.5 (C-8 · 3); 108.5, 108.4 (C-4 · 3); 97.0 (C-100 · 3); 93.7 (C-1 · 3); 77.9 (C-400 ); 72.4 (C-5 0 · 3); 72.1 (C-3 0 · 3); 70.6 (C-2 0 · 3); 68.0 (C-4 0 · 3); 67.0 (C-700 ); 63.2 (C-900 ); 62.4 (C-1000 ); 61.5 (C6 0 · 3); 51.4 (MeO · 3); 48.5 (C-300 ); 47.7 (C-200 ); 40.2 (C500 ); 39.8 (C-6 · 3); 38.9 (C-800 ); 35.8 (C-100 ); 29.9 (C-5 · 3); 21.0, 20.6 (CH3CO · 13); 19.4 (C-600 ); 13.5 (C-10 · 3). 3.7.2. Craigoside B deca-acetate 24 Crystals from cyclohexane, mp 73–75 C, ½a
D ¼ 133 1 (CHCl3, c 0.4). H NMR (CDCl3) d: 7.46, 7.45 (2H, s, H-3 · 2); 6.01 (2H, bq, J = 6.6, H-8 · 2); 5.73, 5.72 (2H, s, H-1 · 2); 5.28 (2H, t, J = 9.4, H-3 0 · 2); 5.15 (2H, t, J = 9.4, H-4 0 · 2); 5.13 (1H, m, H-400 ); 5.12 (2H, dd, J = 9.4, 8.1, H-2 0 · 2); 5.06, 5.04 (2H, d, J = 8.1, H1 0 · 2); 4.33 (2H, dd, J = 12.3, 4.5, Ha-6 0 · 2); 4.11 (2H, dd, J = 12.3, 2.1, Hb-6 0 · 2); 4.00, 3.96 (2H, dd, J = 11.0, 4.8, H-5 · 2); 3.80 (2H, m, J = 9.4, 4.6, 2.1, H-5 0 · 2); 3.71 (6H, s, MeO · 2); 2.71, 2.62 (2H, dd, J = 13.0, 4.8, Ha-6 · 2); 2.45, 2.40 (2H, dd, J = 13.0, 11.0, Hb-6 · 2); 2.11 (1H, m, H-800 ); 2.09, 2.04, 2.03 (30H, s, CH3CO · 10); 1.96 (1H, m, Hb-500 ); 1.84 (1H, m, H-300 );1.76 (6H, d, J = 6.9, H3-10 · 2); 1.65 (1H, m, H- 200 ); 1.52 (1H, m, Ha500 ); 1.05 (3H, d, J = 6.3, H3-600 ). 13C NMR d: 171.3, 170.9 (C-7 · 2); 170.8, 170.7, 170.3, 169.5, 169.0 (CH3CO · 10); 166.9 (C-11 · 2); 153.2 (C-3 · 2); 128.8, 128.7 (C-9 · 2); 125.0, 124.8 (C-8 · 2); 108.8 (C-4 · 2); 97.4, 97.3 (C-1 0 · 2); 94.2, 94.0 (C-1 · 2); 77.8 (C-400 ); 72.8 (C-5 0 · 2); 72.4 (C-3 0 · 2); 71.0 (C-2 0 · 2); 68.5 (C-4 0 · 2); 67.3 (C-700 ); 63.6 (C-900 ); 62.8 (C-1000 ); 61.9 (C-6 0 · 2); 51.6 (MeO · 2); 49.1 (C-300 ); 48.1 (C-200 ); 40.7 (C-500 ); 40.2, 40.1 (C-6 · 2); 39.2 (C-800 ); 36.0 (C-100 ); 30.4, 30.3 (C-5 · 2); 21.0, 20.8 (CH3CO · 10); 19.6 (C-600 ); 13.8, 13.7 (C-10 · 2). 3.7.3. Craigoside C deca-acetate 24 Crystals from cyclohexane, mp 69–71 C, ½a
D ¼ 114 1 (CHCl3, c 0.4). H NMR (CDCl3) d: 7.47 (2H, s, H-3 · 2); 6.01 (2H, bq, J = 7.2, H-8 · 2); 5.71 (2H, bs, H-1 · 2); 5.28 (2H, t, J = 9.6, H-3 0 · 2); 5.14 (2H, t, J = 9.6, H-4 0 · 2); 5.13 (1H, m, H-400 ); 5.12 (2H, dd, J = 9.6, 8.1, H-2 0 · 2); 5.04 (2H, d, J = 8.1, H-1 0 · 2); 4.33 (2H, dd, J = 12.3, 4.2, F.R. Gallo et al. / Phytochemistry 67 (2006) 504–510 Ha-6 0 · 2); 4.07 (2H, dd, J = 12.3, 1.8, Hb-6 0 · 2); 4.02 (2H, dd, J = 11.0, 4.8, H-5 · 2); 3.78 (2H, m, J = 9.6, 4.2, 1.8, H-5 0 · 2); 3.72 (6H, s, MeO · 2); 2.70, 2.69 (2H, dd, J = 13.0, 4.8, Ha-6 · 2); 2.44 (2H, dd, J = 13.0, 11.0, Hb6 · 2); 2.11 (1H, m, H-800 ); 2.08, 2.03, 2.02, 2.00 (30H, s, CH3CO · 10); 1.96 (1H, m, Hb-500 ); 1.84 (1H, m, H-300 ); 1.76 (6H, d, J = 6.9, H3-10 · 2); 1.63 (1H, m, H-200 ); 1.54 (1H, m, Ha-500 ); 1.05 (3H, d, J = 6.6, H3-600 ). 13C NMR d: 171.0, 170.8 (C-7 · 2); 170.5, 170.4, 170.2, 170.0, 169.2, 169.1 (CH3CO · 10); 166.5 (C-11 · 2); 152.9 (C-3 · 2); 128.4 (C-9 · 2); 124.7 (C-8 · 2); 108.5 (C-4 · 2); 97.0, 96.9 (C-1 0 · 2); 93.7, 93.6 (C-1 · 2); 76.9 (C-400 ); 72.4 (C-5 0 · 2); 72.1 (C-3 0 · 2); 70.7 (C-2 0 · 2); 68.1 (C-4 0 · 2); 66.1 (C-700 ); 63.2 (C-900 ); 62.5 (C-1000 ); 61.6 (C-6 0 · 2); 51.3 (MeO · 2); 48.4 (C-300 ); 48.0 (C-200 ); 40.5 (C-500 ); 39.8, 39.7 (C-6 · 2); 38.9 (C-800 ); 35.2 (C-100 ); 30.0, 29.9 (C-5 · 2); 21.0, 20.4 (CH3CO · 10); 19.1 (C-600 ); 13.4 (C-10 · 2). 3.8. Alkaline hydrolysis of craigosides A–C. Methylation with diazomethane Each compound (300 mg) was treated with 0.5 M NaOH (5 ml). After 20 h the solution was neutralized with weakly acid cation-exchanger (H+ form) and concentrated in vacuum to dryness. The residue was dissolved in MeOH and methylated with an ethereal solution of diazomethane. After 2 days the residue obtained by evaporation of the solvents was submitted to CCD with solvent system H2O:nBuOH:EtOAc = 10:7.5:2.5 and dimethyl oleoside, 4, and tetraol iridane, 5, were separated. The former was identified by NMR and rotatory power (Tanahashi et al., 1988). 3.8.1. Tetraol iridane (5) 26 Syrop, ½a
D ¼ þ2:4 (MeOH, c 0.4). Molecular formula C10H20O4, ICR-FTMS m/z: 227.12552 [M + Na]+, calcd 227.12538; FAB-MS m/z: 205, 100 [M + 1]+, 187, 66 [M  17]+. 1H and 13C NMR data in Tables 1 and 2, respectively. 3.9. Acetylation of 5: iridane tetra-acetate (9) Tetraol iridane 5 (28 mg) was acetylated with pyridine and Ac2O (each, 1 ml). After evaporation of the reagents under vacuum, the product was purified by CC (silica gel, solvents cyclohexane:EtOAc = 3:7) to give the correspond23 ing tetra-acetate. Oily, ½a
D ¼ þ14:2 (CHCl3, c 0.3). Molecular formula C18H28O8, FAB-MS m/z: 372 (1, M), 329 (3, M-Ac), 313 (3, M-AcO), 269 (45, M-Ac-AcOH), 150 (100). 1 H NMR (CDCl3) d: 5.12 (1H, quintet, J = 6.0, 3.0, 3.0, H400 ); 4.17, 4.05 (2H, m, H2-900 ); 4.13, 3.99 (2H, m, H2-1000 ); 4.11, 4.00 (2H, m, H2-700 ); 2.11 (1H, m, J = 6.3, H-800 ); 2.08, 2.06, 2.05, 2.02 (12H, s, CH3CO · 4); 1.96 (1H, m, J = 9.0, 6.3, 3.0, H-300 ); 1.94 (1H, m, J = 10.5, 9.0, 6.8, 6.6, H-100 ); 1.83 (1H, m, J = 13.5, 6.8, 3.0, Hb-500 ); 1.63 (1H, m, J = 9.0, 9.0, H-200 ); 1.52 (1H, dq, J = 13.5, 10.5, 6.0, Ha -500 ); 1.07 (3H, d, J = 6.6, H3-600 ). 13C NMR d: 169.9 (CH3CO · 4); 77.1 (C-400 ); 66.1 (C-700 ); 63.4 (C-900 ); 62.4 (C-1000 ); 48.6 509 (C-300 ); 48.1 (C-200 ); 40.5 (C-500 ); 39.0 (C-800 ); 35.2 (C-100 ); 21.1, 20.7 (CH3CO · 4); 19.1 (C-600 ). 3.10. (S)-MTPA tetra-ester of 5 (10) A suspension of 5 (40 mg) in anhydrous CH2Cl2 (15 ml) was added with (S)-MTPA (188 mg), DMAP (26 mg) and then with DCC (176 mg). After 2 days of stirring, more (S)- MTPA (45 mg) and DCC (46 mg) were added. After 2 days the mixture was diluted with water and extracted with additional CH2Cl2. The residue of the evaporation of the organic phase was submitted to CC (silica gel, solvents cyclohexane:EtOAc=8:2) and the tetra acyl derivative 10 was obtained. Molecular formula C50H48O12F12, ICR-FTMS m/z: 1091.28111 [M + Na]+, calcd 1091.28464. 1H NMR (CDCl3) d: 7.47-7.37 (20H, m, ArH5 · 4); 5.15 (1H, m, H400 ); 4.26 (1H, dd, J = 11.4, 4.9, Hb-1000 ); 4.22 (1H, dd, J = 12.0, 4.4, Ha-1000 ); 4.13, 4.11 (2H, m, H2-700 ); 4.08 (1H, m, Hb-900 ); 3.93 (1H, dd, J = 11.4, 6.8, Ha-900 ); 3.50, 3.47, 3.45 (12H, s, MeO · 4); 2.05 (1H, m, H-800 ); 1.81 (1H, m, H-300 ); 1.69 (1H, m, Hb-500 ); 1.65 (1H, m, H-100 ); 1.46 (1H, m, H-200 ); 1.16 (1H, m, Ha-500 ); 0.83 (3H, d, J = 6.2, H3-600 ). 13 C NMR d: 166.2 (CO · 4); 132.2 (C Ar1 · 4); 129.8, 128.7, 127.4, 127.3 (C Ar2-6 · 4); 122.3 (CF3 · 4); 84.3 (C1 · 4); 79.6 (C-400 ); 68.0 (C-700 ); 64.3 (C-900 ); 63.3 (C-1000 ); 55.6, 55.3 (MeO · 4); 48.9 (C-300 ); 48.1 (C-200 ); 40.0 (C-500 ); 38.8 (C-800 ); 35.2 (C-100 ); 18.7 (C-600 ). 3.10.1. (R)-MTPA tetra-ester of 5 (11) Tetraol 5 was likewise treated with (R)-MTPA and tetra acyl derivative 11 was obtained. Molecular formula C50H48O12F12, ICR-FTMS m/z: 1091.27944 [M + Na]+, calcd 1091.28464. 1H NMR (CDCl3) d: 7.47–7.36 (20H, m, ArH5 · 4); 5.09 (1H, m, H-400 ); 4.36 (1H, dd, J = 11.7, 5.1, Hb-1000 ); 4.10 (1H, m, Ha-1000 ); 4.08, 4.06 (2H, m, H2-700 ); 3.98, 3.92 (2H, m, H2-900 ); 3.49, 3.47 (12H, s, MeO · 4); 2.04 (1H, m, H-800 ); 1.81 (1H, m, Hb-500 ); 1.74 (1H, m, H100 ); 1.73 (1H, m, H-300 ); 1.54 (1H, m, H-200 ); 1.37 (1H, m, Ha-500 ); 0.86 (3H, d, J = 6.0, H3-600 ). 13C NMR d: 165.9 (CO · 4); 132.0 (C Ar1 · 4); 129.7, 128.5, 127.2 (C Ar26 · 4);121.4 (CF3 · 4); 84.4 (C-1 · 4); 79.3 (C-400 ); 67.9 (C700 ); 63.9 (C-900 ); 63.5 (C-1000 ); 55.3 (MeO · 4); 48.7 (C-300 ); 47.8 (C-200 ); 39.8 (C-500 ); 38.9 (C-800 ); 35.4 (C-100 ); 18.7 (C-600 ). Acknowledgements The authors thank Professor Marcello Nicoletti (Università La Sapienza Rome, Italy) for his NMR data support. References Chifundera, K., 2001. Contribution to the inventory of medicinal plants from the Bushi area, South Kivu Province, Democratic Republic of Congo. Fitoterapia 72, 351–368. Craig, L.C., Post, O., 1949. Apparatus for countercurrent distribution. Anal. Chem. 21, 500–504. 510 F.R. Gallo et al. / Phytochemistry 67 (2006) 504–510 Ohtani, I., Kosumi, T., Kashman, Y., Kakisawa, H., 1991. High-field FTNMR application of MosherÕs method. The absolute configuration of marine terpenoids. J. Am. Chem. Soc. 13, 4092–4096. Shen, Y.C., Hsieh, P.W., 1997. Four new secoiridoid glucosides from Jasminum urophyllum. J. Nat. Prod. 60, 453–457. Tanahashi, T., Nagakura, N., Inoue, K., Inouye, H., 1988. Sambacosides A, E and F, novel tetrameric iridoid glucosides from Jasminum sambac. Tetrahedron Lett. 29, 1793–1796. Tanahashi, T., Nagakura, N., Kuwajima, H., Takaiski, K., Inoue, K., Inouye, H., 1989. Secoiridoid glucosides from Jasminum mesnyi. Phytochemistry 28, 1413–1415. Tanahashi, T., Takenaka, Y., Nagakura, N., Nishi, T., 2000. Five secoiridoid glucosides esterified with a cyclopentanoid monoterpene unit from Jasminum nudiflorum. Chem. Pharm. Bull. 48, 1200–1204. Zhang, Y.J., Liu, Y.Q., Pu, X.Y., Yang, C.R., 1995. Iridoidal glycosides from Jasminum sambac. Phytochemistry 38, 899–903.