Gomojosides, labdane diterpenoids from Viburnum suspensum

Phytochemistry,

Vol. 31, No. 4, pp. 1311-1315,

Printed in Great Britain.

1992

003 l-9422/92 $5.00 + 0.00 Q 1992 Pergamon Press plc

GOMOJOSIDES, LABDANE DITERPENOIDS VIBURNUM SUSPENSUM TETSUO IWAGAWA, SHIGETOSHI YAGUCHI, TSUNAO HASE, TSUTOMU OKUBO*

FROM

and MUJO KIM*

Department of Chemistry, Faculty of Science, Kagoshima University, Korimoto 1-21-35, Kagoshima 890, Japan; *Taiyo Kagaku Co. Ltd, l-3 Takaramachi, Yokkaich 510, Japan (Received

Key Word Index-Wmrnum antibacterial activity.

9 July

1991)

suspensum; Caprifoliaceae; diglucosides of labdane diterpenes; gomojosides A--J;

Abstract-Ten new labdane-type diglucosides, gomojosides A-J, have been isolated from Viburnum suspensum, and their structures elucidated by spectroscopic methods. Five of gomojosides isolated showed potent antibacterial activity.

INTRODUCTION

In previous papers, we have reported on the isolation and structural elucidation of iridoid glycosides, including bitter principles, from Viburnum suspensum L. [l, 21. Further investigation on this plant has resulted in the isolation of 10 new labdane-type diglucosides, which we have named gomojosides A (l), B (2), C (3), D (4), E (S), F (6), G (7), H (8), I (9) and J (10) following the Japanese name of the plant (gomoju). We describe the isolation and characterization of the new diterpenoids.

RESULTS

AND

DISCUSSION

Gomojosides A-J were isolated by repeated conventional column chromatography on activated charcoal, silica gel and HPLC. Their molecular formulae were determined by ‘H, ’ 3C NMR and mass spectrometry. The presence of two b-glucopyranose units in each of the compounds was established by ‘H, ‘jCNMR and mass spectrometry (Table 1). Gomojoside A (1) was isolated as needles, C,,H,,O,,. It showed IR absorption bands for a hydroxy group at 3300 cm-‘, an ester carbonyl at 1720 cm-’ and an exomethylene group at 1640 and 890 cm-‘. It gave an octaacetate, C,,H,,02,. The ‘H NMR spectrum of 1 showed that it has a typical labdan-8(17),13-diene skeleton CS4.53 (br s, H-17: the other peak for H-17 was hidden in the signal due to CD,OD); 65.31 (t, J = 6.8 Hz, H-14)]. The spectrum also indicated the presence of three tertiary methyl groups at 60.62, 1.25 and 1.68 (3H each, s), suggesting that the 18-, 19- or 20-methyl group was oxidized to a carboxylic acid, which was attached through an ester linkage to a hydroxyl group at C-l in the glucose residue C65.41 (lH, J = 7.7 Hz, H-l’); 695.6 (C-l’)]. In the 13CNMR spectrum, signals due to C-l&C-10, C-18 and C-20 appeared at similar positions to those of trans-methyl communate [3]. This proves that the methyl group at C-19 is oxidized and has a cisrelationship with the methyl group at C-20. The Egeometry of the side chain was also established by the

chemical shift of the methyl carbon at C-13 (S 16.4). The chemical shift (6 ca 4.30) of the methylene group at C-l 5, which was coupled to the proton at C-14, indicated that the methylene group is hydroxylated. Thus the remaining glucose to be assigned is attached to the hydroxyl group at C-15. It is, therefore, concluded that gomojoside A is the 19-fl-glucopyranosyl ester of labda-8(17),13E-dien15-O-b-glucopyranosyl-19-oic acid. The structures of other gomojosides were determined in a similar manner. The ‘HNMR spectrum of gomojoside B (2), C,,H,,O,,, was similar to that of 1, except that methyl signal at C-13 appeared as a doublet at 60.91 (3H, d, J = 6.6 Hz) and the olefinic proton signal at C-14 was absent. The ’ 3C NMR spectrum lacked the corresponding signals for olefinic carbons at C-13 (6 142.7) a.nd C-14 (6 121.7) and instead contained methylene and methine signals at 638.2 and 31.5, respectively. Therefore, the structure of 2 is 13,14-dihydrogomojoside A. The ‘HNMR spectrum of gomojoside C (3), showed a close similarity to that of 1 in C32H54012, which the anomeric proton of the glucose linked to the carboxylic group at C-19 was shifted to 64.17 (d, J = 8.1 Hz) and a new signal due to hydroxymethylene protons appeared at S 3.21 and 4.09 (AB, J = 9.3 Hz). From the above data, 3 was assigned to be the 15,19-di0-/?-glucopyranoside of labda-8(17),13E-dien-15,18-diol. Gomojoside D (4), C,,H,,O,,, is a dihydro derivative of 3. While the signal due to the olefinic proton at C-14 was missing in the ‘H NMR spectrum, the methyl signal at C-13 was observed as a doublet at 60.91 (J = 6.2 Hz). In the 13CNMR spectrum the signals assignable to the olefinic carbons at C-13 (6 142.6) and C-14 (6 121.6) were shifted to 631.5 (methine carbon ) and 38.2 (methylene carbon), respectively, suggesting that the double bond between C-13 and C-14 in 4 was hydrogenated. Thus, the structure of 4 is 13,14-dihydrogomojoside C. The molecular formula of gomojoside E (5), C32H54013 has one more oxygen than that of 3. The additional oxygen was attributed to a hydroxyl group, due to the similarity of the NMR spectra to those of 3. The position of the hydroxyl group was determined to be

1311

T. IWAGAWA

1312

R’ 1

H

3 5

H

H

8H

10 OGlc

R2 CO,Glc CH20Glc CHzOGlc Me Me

R” H H OH OGIC

et al.

2 4 6 9

R’ CO,Glc

RZ H

CH,OGlc CH,OGlc Me

H OH OGIC

H

CHzOGlc

at C-6, as the chemical shift (625.7) of C-6 in the 13CNMR spectrum of 3 was shifted upfield to 672.1. The a-equatorial configuration of the hydroxyl group was established by the diaxial coupling constant (J = 11.3 Hz) between the protons at C-5 and C-6. Compound 5, therefore, should be 15,19-di-0-/?-glucopvranoside of labda-8(17),13E-dien-6,15,19-triol. --The structure of gomojoside F (6), C32H56013, was readilv assignable bv comnarison of its NMR snectra with those lf 5. While the dlefinic proton (65.33) ai C-14 was not found, the vinylic methyl group at C-13 appeared at 60.92 as a doublet (J = 6.6 Hz) in the ‘HNMR spectrum of 6. In the 13CNMR spectrum the olefinic carbons at 6121.8 and 142.5 were replaced by a methylene and a methine carbons at 638.2 and 31.5, respectively.Based on the above data, 9 is 13,14-dihydrogomojoside E. The IR spectrum of gomojoside G (7), C32H54013 indicated the presenceof an a&unsaturated carbonyl at 1665 and 1635cm-’ as well as a hydroxyl group at 3400 cm- I. The ‘H NMR spectrum was similar to that of 4, except that the exomethylene protons at C-17 were absent and a methyl proton at 61.97 (s) and an olefinic proton at 65.71 (lH, br s) were observed. The carbonyl was thus situated at C-6. Compound 7 is, therefore, 15,19di-O-p-glucopyranoside of 6-oxo-labda-7-en-15,19-diol. Gomojoside H (S),C32H54012, showed typical spectral characteristics of a labda-8,(17),13&diene skeleton C64.61 and 4.93 (1H each, br s), H-17; 65.32 (lH, t, J = 6.6 Hz), H-141. The ‘HNMR spectrum contained signals due to four methyl groups at 60.73, 1.07, 1.17 and 1.68, suggesting that the methyl group at C-19 remained intact, in contrast to compounds 1-7. A triplet doublet signal CS4.00(lH, J = 4.8 and 11.0 Hz)] due to a proton on a carbon bearing a glucosyl group was coupled to both a proton at 6 1.36 (d, J = 10.8 Hz) and methylene protons at 62.08 (lH, t, J = 11.9 Hz) and 2.86 (lH, dd, J = 4.8 and 11.9 Hz). Therefore, the glucosyl group must be attached to C-6 or C-11. However, the latter altern-

ative position for the glucosyl group was discarded, since the chemical shift (S ca 1.7) of the proton at C-9 was observed at a similar position to those in l-4. The transrelationship between the protons at C-5 and C-6 was deduced from the diaxial coupling constant (J = 10.8 Hz). Gomojoside H is, thus, 6,15-di-o-glucopyranosides of labda-8(17),13E-dien-6B,15-diol. The structure of gomojoside I (9), C32H56012, is 13dihydrogomojoside H. This was deduced from the similarity of its ‘H NMR spectrum to that of 8. Compound 9 differed from 8 in the absence of an olefinic proton and the presence of a secondary methyl group at 60.91 (d, J = 6.6 Hz). Gomojoside J (lo), C,,H,,O,,, is an isomer of 9. In the ‘H NMR spectrum (in pyridine-d,) a proton attached to a carbon bearing a glucosyl group was observed at 63.68 (dd, J = 4.2 and 11.6 Hz), suggesting that the position of the glucosyl group at the /Sposition of C-l or C-3. Placement of the glucosyl group at C-3/? was established by a NOE between H-3~ (6 ca 3.38) and H-18 at 61.05 (2.2%) (in CD,OD). This is the first report of the isolation of labdane diterpenoids from Viburnum species,although there are many reports on valeriana iridoid glycosides from Viburnum species[l, 2, 4-S]. The study of the labdane diterpenes may be of chemotaxonomical value. Antibacterial activity tests were performed on compounds l-10 using the paper disc method (8 mm diam. and 1.5 mm thick). Compounds 2, 3, 57 appeared to have potent antibacterial activity at 500 ppm concentration in nutritional agar medium against E. coli and compound 10 against B. subtilis.

EXPERIMENTAL

Mps: uncorr. ‘H NMR and 13C NMR standard): 400 and 100 MHz, respectively.

(CD,OD,

TMS

as int.

Labdane Table C

2 4 5 6 8 9 10 11 12 13 14 15 16 17 18 19 20 1’ 2 3' 4' 5’ 6

1. ‘WNMR

spectral

diterpenoids data

of

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

“These

values

Viburnum

compounds

l-10

suspnsum

(CD,OD,

1313 TMS

as int. standard)

1

2

3

4

5

39.20 21.15 40.46 45.73 56.44 27.28 39.48 149.54 57.97 41.55 22.89 39.90 142.68 121.67 66.12 16.42 106.93 29.34 177.84 13.90 102.49, 75.09, 78.74," 71.76, 78.32," 62.86,

40.45 21.19 39.30 45.71 57.85 27.28 39.99 149.78 58.09 41.68 22.35 37.57 31.49 38.18 69.30 20.03 106.93 29.37 177.82 13.86 104.52, 75.19, 78.74," 71.75, 78.19," 62.86,

40.36 20.13 37.23 40.66 57.77 25.72 39.79 149.67 s7.47 39.44 22.86 39.44 142.62 121.56 66.24 16.47 107.01 28.34 73.52 15.97 105.12, 75.37, 78.28," 71.73 78.08," 62.83,

40.35 20.13 37.28 40.74 57.84 25.70 39.85 149.86 58.72 39.41 22.16 37.45 31.50 38.15 69.29 20.02 107.03 28.37 73.50 15.94 105.10, 75.30, 78.26," 71.72 77.92," 62.84,

40.68 19.97 39.75 39.43 61.61 72.09 49.54 147.30 56.75 40.35 22.51 39.49 142.45 121.74 66.26 16.48 108.61 31.82 75.43 17.49 104.93, 75.33, 78.35," 71.74 78.12," 62.86,

95.57 74.06 78.64" 71.20 78.11" 62.50

95.57 74.06 78.65" 71.19 77.96" 62.50

Table C

from

102.65 75.11 78.26" x 2 77.77" 62.80

7

8

9

40.66 19.97 39.80 39.39 61.64 72.02 49.45 147.50 58.01 40.42 22.45 37.50 31.50 38.15 69.26 20.03 108.59 31.81 75.41 17.45 104.90, 75.30, 78.33", 71.71 77.95 62.84,

40.73 18.87 39.69 44.59 65.66 202.69 128.55 163.36 58.33 38.49 25.87 36.96 31.45 37.86 68.98 20.01 22.50 27.69 71.27 16.01 105.30, 75.40, 78.24", 71.80, 77.98", 62.90,

40.47 20.28 45.61 35.20 60.06 78.02 44.75 146.93 56.49 40.73 22.81 39.36 142.43 121.80 66.09 16.35 108.56 37.44 22.46 16.84 102.45, 75.42, 78.16", 72.26, 77.74", 63.37,

40.62 20.26 45.65 35.13 60.04 77.36 44.84 147.22 57.86 40.73 22.40 38.13 31.47 38.13 69.24 20.03 108.59 37.44 22.40 16.73 104.46, 75.40, 78.20", 72.21, 77.89", 63.35,

may

be interchangeable

104.49 75.20 78.18" 71.77 77.72" 62.79

in any vertical

102.71 75.13 78.26" x 2 77.98" 62.80

1. (Continued)

6

104.52 75.17 78.18" x 2 x 2 62.77

104.50 75.15 78.17" x 2 77.73" 62.80

column.

101.02 75.07 78.11” 71.74 77.30" 62.82

10

101.08 75.13 78.13 71.67 77.71" 62.82

38.25 24.89 85.84 39.62 56.51 25.30 39.23 149.60 56.63 40.29 22.62 39.35 142.85 121.67 65.86 16.36 107.14 29.00 15.12 17.11 102.17, 75.20, 78.36", 72.06, 78.12", 63.18,

102.02 75.03 78.27" 71.77 77.73" 62.87

1314

T.IwAGAWA

Extraction and isolation. The extraction and isolation procedure was almost the same as described in our previous work [2]. The n-BuOH extract (50 g) was subjected to CC on activated charcoal with H,O-MeOH containing increasing proportions of MeOH and then CH,Cl,. The frs (4.6 g) eluted with CH,Cl, were further chromatographed on ODS with H,O-MeOH (1:4) to give needles of gomojoside A (1) (86 mg). Further elution with H,O-MeOH (1:4) afforded a residue, which was subjected to CC of silica gel with MeOH-CH,C& with increasing proportions of MeOH. Elution with MeOH-CH,CI, (3: 17) gave gomojoside C (3) (85 mg), needles, mp 166168”, from the mother liquor of which gomojosides D (4) (75 mg), H (8) (28 mg), I (9) (26 mg) and J (10) (20 mg) were isolated by use of HPLC with H,O-MeOH (13:7). Chromatography of the residue with MeOH-CH,C& (1:9-4: 1) gave a mixture which was separated by HPLC with H,O-MeOH (9: 11) yielding gomojosides B (2) (3 mg), E (5) (5 mg) and F (6) (13 mg). The other n-BuOH extract (21 g) was also subjected to CC on activated charcoal as described above. The frs (7.8 g) eluted with MeOH-CH,Cl, (1: 1) and CH,Cl, were applied to CC (ODS with H,O-MeOH, 2:3; silica gel with MeOH-CH,Cl,, 3:20-1:4) and then HPLC with H, O-MeOH (9: 11) to afford gomojosides E (5) (17 mg) and J (7) (14 ms). Gomojoside A (1). Needles from H,O-MeOH, mp 135-137”, [tx]o - 45.8” (MeOH; c 0.24); UV 1:;:” nm (logs): 216 (3.12); IR vfjJ$ cm-‘: 3300,1720,‘1640, 890; ‘H NMR: 60.62 (3H, s, H-20), 1.25 (3Hs, H-18), 1.68 (3H, s, H-16), 3.65-3.69(2H, m, H-6’), 3.80 (lH, br d, J= 11.7 Hz, H-6’), 3.86 (lH, dd, J= 1.5 and 11.7 Hz), 4.28-4.32 (3H, m, H-15 and H-l’), 4.53 (lH, br s, H-17), 5.31 (lH, t, J = 6.8 Hz, H-14), 5.41 (lH, d, J = 7.7 Hz, H-l’); i3CNMR: see Table 1. SIMS: m/z 645 [M + 11’. Gomojoside B (2). Amorphous powder, [a],, - 53.5” (MeOH; cO.093); uv a”,:;” nm (logs): 210 (3.18); IR vi\: cm-‘: 3350, 1740, 1640, 890; ‘HNMR: 60.61 (3H, s, H-20), 0.91 (d, J = 6.6 Hz, H-16), 1.24 (3H, s, H-18), 3.54 (lH, br dd-like, J=7.3 and 15.4 Hz, H-15), 3.64-3.70 (2H, m, H-6’), 3.81 (lH, dd, J = 1.8 and 12.1 Hz, H-6’), 3.86(1H, dd, J = 3.2 and 13.1 Hz, H-6’), 3.94(1H, br dd, J = 7.7 and 15.4 Hz, H-6’), 4.24 (lH, d, J = 7.7 Hz, H-l’), 4.51 (lH, br s, H-17), 5.42 (lH, d, J = 7.7 Hz, H-l’); i3CNMR: see Table 1. SIMS: m/z 669 [M + Na]+. Gomojoside C (3). Needles from H,O-MeOH, mp 1666168”, [LY]~ - 65.2” (MeOH; c 0.23); UV 1~~~” nm (logs): 214 (3.11); IR vale cm-‘: 3300, 1640, 890; ‘HNMR: 60.70 (3H, s, H-20), 1.04 (3H, s, H-18) 1.68 (3H, s, H-16), 3.21 (lH, d, J = 9.3 Hz, H15), 3.67 (lH, d, J = 11.7, H-6’) 3.68 (lH, d, J = 12.1 Hz, H-6’), 3.85 (3H, dd, J = 2.2 and 11.7 Hz, H-6’), 3.87 (lH, dd, J = 2.2 and 12.1 Hz, H-6’), 4.09 (lH, d, J = 9.3 Hz), 4.17 (lH, d, J = 8.1 Hz, H-l’), 4.26 (lH, dd, J = 7.7 and 11.9 Hz, H-15), 4.33 (lH, dd, J =6.6 and 11.9 Hz, H-15), 4.53 (lH, br s, H-17) 5.32 (lH, t, J = 6.4 Hz, H-14); ‘sCNMR: see Table 1. SIMS: m/z 631 [M + 11’. Gomojoside D (4). Amorphous powder, [a],, - 77.1” (MeOH; ~0.233); UV n;$r’ nm (logs): 211 (3.08); IR vz:; cm-‘: 3350, 1640, 890; ‘H NMR: 60.96 (3H, s, H-20), 0.91 (3H, d, J = 6.2 Hz, H-16), 1.03 (3H, s, H-18), 2.38 (lH, br d, J = 12.5 Hz, H-7), 3.19 (lH, d, J = 9.5 Hz, H-19), 3.54 (IH, dd, J = 7.0 and 16.1 Hz, H15), 3.65-3.70 (2H, m, H-6’), 3.83-3.87 (2H, m, H-6’), 3.94 (lH, br dd, J = 8.6 and 16.1 Hz, H-15), 4.09 (lH, d, J = 9.5 Hz, H-19) 4.17 (lH, d, J = 7.7 Hz, H-l’), 4.24 (lH, d, J = 7.7 Hz, H-l’), 4.51 (lH, br s, H-17), 4.80 (lH, br s, H-17); iaCNMR: see Table 1. SIMS: m/z 655 [M + Na]+. Gomojoside E (5). Amorphous powder, [a]n - 112.5” (MeOH; c 0.25); UV ,%:$‘r’ nm (logs): 214 (3.29); IR v~~~ccm-‘: 3350, 1650, 895; ‘HNMR: 60.75 (3H, s, H-20), 1.27 (3H, s, H-18), 1.69 (3H, s, H-16), 2.07 (lH, t, J = 11.7 Hz, H-6a), 2,60(1H, dd, J = 4.6 and 12.3 Hz, H-6&, 3.67 (lH, dd, J = 1.5 and 13.6 Hz, H-6’), 3.68 (lH, dd, J = 1.5 and 12.1 Hz, H-6’), 3.73 and 3.97 (1H each, d, J

et al. = 9.5 Hz, H-19), 3.84-3.88 (2H, m, H-6’), 4.25 (lH, d, J = 7.7 Hz, H-l’), 4.29 (lH, d, J = 8.1 Hz, H-l’), 4.61 and 4.90 (1H each, br s, H-17), 5.33 (lH, t, J=7.0Hz, H-14); t3CNMR: see Table 1. SIMS: m/z 669 [M + Na]‘. Gomojoside F (6). Amorphous powder, [m]o - 72.9” (MeOH, ~0.24); UV 1::;” nm (logs): 211 (3.11); IR vgi: cm-‘: 3350, 1645, 895; ‘H NMR: 60.74 (3H, s, H-20), 0.92 (3H, d, J = 6.6 Hz, H-16), 1.27 (3H, s, H-18), 2.05 (lH, t, J = 11.5 Hz, H-6x), 2.59 (lH, dd, J = 4.6 and 12.3 Hz, H-68), 3.55 (lH, dd, J = 7.3 and 16.5 Hz, H-15), 3.65-3.70 (2H, m, H-6’), 3.73 and 3.96 (1H each, d, J = 9.5 Hz, H-19), 3.85-3.88 (2H each, m, H-6’), 3.93 (lH, m, H-15), 4.24 (lH, d, J = 7.7 Hz, H-l’), 4.25 (lH, d, J=8.1 Hz, Hl’), 4.59 and 4.87 (1H each, br s, H-17); i3C NMR: see Table 1. SIMS: m/z 671 [M+Na]+. Gomojoside G (7). Amorphous powder, [aIn - 15.5” (MeOH; ~0.19); UV1/lyHnm (logs): 252 (3.51); IRv~~~cm-i: 3400 1665, 1635; ‘HNMR: 60.82 (3H, s, H-20) 0.97 (3H, d, J=6.2 Hz, H-16), 1.22 (3H, s, H-18), 1.97 (3H, s, H-17) 2.34 (lH, s, H-S), 3.55-3.61 (lH, m, H-15), 3.643.70 and 3.83-3.88 (1H each, m, H6’), 3.974.03 (lH, m, H-15), 4.04 and 4.12 (1H each, d, J=9.3 Hz, H-19) 4.25 (lH, d, J=7.7Hz, H-l’), 4.25 (lH, d, J=8.1Hz, H-l’), 5.71 (lH, br s, H-8); ‘“CNMR: see Table 1. SIMS: m/z 669 [M +Na]+. Gomojoside H (8). Amorphous powder, [alo - 82.4” (MeOH; ~0.257); UV n:;p nm (log E): 213 (3.13); IR v,r$;cm-i: 3350, 1640, 890; ‘HNMR: 60.73 (3H, s, H-20), 1.07 (3H, s, H-19), 1.17 (3H, s, H-18), 1.36 (lH, d, J=ll.O), 1.68 (3H, s, H-16) 1.95 (lH, dt, J=8.1 and 13.9 Hz, H-12), 2.08 (lH, t, J=11.9 Hz, Ha-7), ca 2.18 (lH, m, H-12), 2.86 (lH, dd, J=4.8 and 11.9 Hz Hfi-7), 3.66 (lH, dd, J=6.6 and 11.9 Hz, H-6’), 3.78 (IH, dd, J=5.3 and 12.1 Hz, H-6’), 3.870 (lH, dd, J=2.2 and 12.1 Hz, H-6’), 3.874 (lH, dd, J=3.0 and 11.9 Hz, H-6’), 4.00 (lH, dd, J=4.8 and 10.6 Hz, H-6), ca 4.29 (2H, m, H-19), 4.31 (LH, d, J=8.1, H-l’), 4.41 (lH, d, J=7.7 Hz, H-l’), 4.61 (lH, br s, H-17), 4.93 (lH, br s, H-17), 5.32 (lH, t, J=6.6 Hz, H-14); ‘%NMR: see Table 1. SIMS: m/z 653 [M+Na]+. Gomojoside I (9). Amorphous powder, [a&-68.2” (MeOH; ~0.257); UV 1::;” nm (logs): 211 (3.05); IR v~~;crn-i: 3350, 1640, 890; ‘HNMR: 60.72 (3H, s, H-20) 0.91 (3H, d, J=6.6 Hz, H-16), 1.07 (3H, s, H-19), 1.16 (3H, s, H-18), 1.34 (lH, d, J = 10.6, H-5), 2.04 (lH, t, J = 11.4Hz, HE-~), 2.86 (lH, dd, J=4.8 and 12.5 Hz, HP-7), 3.54(1H, brdd, J=7.1 and 16.3, H-15), 3.64-3.69 (2H, m, H-6’), 3.85-3.89 (2H, m, H-6’), ca 3.95 (lH, m, H-15), 3.99 (lH, dt, J=4.8 and 10.6, H-6), 4.24(1H, d, J=7.7 Hz, H-l’), 4.40 (IH, d, J=7.7 Hz, H-l’), 4.59 (lH, br s, H-17); “CNMR: see Table 1. SIMS: m/z 655 [M + 11’. Gomojoside J (10). Amorphous powder, [alo - 56.3” (MeOH; ~0.24); UV 2::;” nm (loge): 212 (3.11); IR v~~~cm-‘: 3350, 1640, 890; ‘HNMR: 60.73 (3H, s, H-20), 0.81 (3H, s, H-19), 1.05 (3H, s, H-18), 1.69 (3H, s, H-16), ca 3.38 [(lH, m): 63.68 (dd, J = 4.2 and 11.6 Hz) in pyridine-d,, H-3a], 3.68 (lH, dd, J=5.5 and 12.1 Hz, H-6’), 3.87 (lH, dd, J=2.2 and 12.1 Hz, H-6’), 4.29 (2H, m, H-15), 4.31 and 4.33 (1H each, d, J=8.1 Hz), 4.54 and 4.82 (1H each, br d, H-17), 5.29 (lH, t, J=6.8 Hz); i3C NMR: see Table 1. SIMS: m/z 653 [M +Na]+. Acetylation of compound 1. A soln of 1 (7 mg) in Ac,O and pyridine was allowed to stand at room temp. overnight. The crude product was chromatographed over silica gel with CHCl, to give an octa-acetate (7 mg), an amorphous powder; IR vE:T cm-‘: 1750,1640,1220,980,900; ‘HNMR (CD&): 60.52 (3H, s, H-20), 1.22 (3H, s, H-19), 1.58 (3H, s, H-16), 2.00-2.08 (3H x 8, s, OAc), 3.67 (lH, ddd, J=2.6, 5.1 and 9.9 Hz, H-S’), 3.80 (lH, ddd, J = 2.6,4.8 and 10.1 Hz, H-5’), 4.07 (lH, dd, J = 2.6 and 12.5 Hz, H-6’), 4.16 (lH, dd, J=2.6 and 12.5 Hz, H-6’), 4.52 and 4.85(1Heach,brs,H-17),4.54(1H,d,J=8.1 Hz,H-1’),5.67(1H, d, J=8.1 Hz, H-l’); FAB-MS: m/z: 1003 [M+Na]+.

Labdane

diterpenoids

Acknowledgements-We thank Dr 0. Tanaka (Hiroshima University) for samples of goshonosides. We are grateful to Miss S. Seo (Otsuka Chemical Co., Ltd) for the SIMS measurements.

REFERENCES

1. Iwagawa, 2. Iwagawa, 29, 310.

T. and Hase, T. (1989) Phytochemistry 28, 2393. T., Yaguchi, S. and Hase, T. (1990) Phytochemistry

from

Viburnum

suspensum

1315

3. Stipanovic, R. D., O’Brien, D. H., Rogers, C. E. and Thompson, T. E. (1979) J. Agric. Food Chem. 27, 458. 4. Bock, K., Jensen, S. R., Nielsen, B. J. and Norn, V. (1978) Phytochemistry 17, 753. 5. Jensen, S. R., Nielsen, B. .I. and Norn, V. (1985) Phytochemistry 24, 487. 6. Hase, T., Iwagawa, T. and Muanza, N. D. (1985) Phytochemistry 24, 1323. 7. Iwagawa, T. and Hase, T. (1986) Phytochemistry 25, 1227. 8. Handjieva, N., Baranovska, I., Mikhova, B. and Papov, S. (1988) Phytochemistry 27, 3175.