Helvetica Chimica Acta – Vol. 92 (2009)
1501
Optical rotation: Jasco-P-1020 digital polarimeter. IR Spectra: Nicolet-Nexus-470 spectrophotometer; ˜n
1
in cmꢀ1. H- and 13C-NMR Spectra: Jeol-Eclips-600 spectrometer; at 600 (1H) and 150 MHz (13C); d in
ppm rel. to Me4Si as internal standard, J in Hz. ESI- and HR-ESI-MS: Q-TOF-Ultima-Global-GAA076
LC mass spectrometer; in m/z. GC/MS System: Agilent-6890 gas chromatograph and Agilent-5973 mass-
selective detector in the EI mode.
Animal Material. Specimen of the soft coral S. infundibuliforme were collected from the Wenchang
coral reef at a depth of ꢀ 10 m in the South China Sea, in November 2006 and were frozen immediately
after collection. The animal was identified by H. H. of the South China Sea Institute of Oceanology,
Chinese Academy of Sciences. A voucher sample (No. WCLL-1 – 4) is available for inspection at the
Ocean University of China.
Extraction and Isolation. The frozen specimen (460.0 g, dry weight) were cut into pieces and
extracted exhaustively with 95% EtOH (3 ꢁ 1000 ml) at r.t. The EtOH extract was evaporated to give a
residue (18.0 g) which was partitioned between AcOEt (3 ꢁ 600 ml) and H2O (300 ml), and then
between BuOH (3 ꢁ 400 ml) and H2O (300 ml), successively. The BuOH soln. was concentrated to give a
dark green residue (4.8 g) which was fractionated by CC (SiO2, 0 ! 100% MeOH/CHCl3): Fractions A –
D. The bioactive Fr. D (270.0 mg) was purified by CC (Sephadex LH-20, CHCl3/MeOH 1:1) followed by
reversed-phase CC (SiO2 (ODS)): 1 (12.0 mg), 2 (6.4 mg), and 3 (10.0 mg). The AcOEt-soluble portion
(7.0 g) was separated by CC (SiO2, 0 ! 100% AcOEt/petroleum ether): Frs. 1 – 10 (by TLC). Fr. 7
(268 mg) was subjected to CC (Sephadex LH-20, CHCl3) and further purified by CC (SiO2, petroleum
ether/acetone 6 :1 ! 7:3): 4 (38.5 mg) and 5 (160.0 mg).
Sarcoglycoside A (¼(6Z,9Z,12Z,15Z)-Octadeca-6,9,12,15-tetraenoic Acid (2R)-3-[(6-O-a-galacto-
pyranosyl-b-d-galactopyranosyl)oxy]-2-hydroxypropyl Ester; 1): White amorphous powder. [a]D22
¼
þ20.8 (c ¼ 0.30, MeOH). IR (KBr): 3350, 2926, 1739, 1693, 1534, 1076, 1023, 678. 1H-NMR
((D6)DMSO): 5.30 – 5.40 (m, HꢀC(6’), HꢀC(7’), HꢀC(9’), HꢀC(10’), HꢀC(12’), HꢀC(13’),
HꢀC(15’), HꢀC(16’)); 2.75 – 2.80 (m, 2 HꢀC(8’), 2 HꢀC(11’), 2 HꢀC(14’)); 2.31 (t, J ¼ 7.0,
2 HꢀC(2’)); 2.01 – 2.06 (m, 2 HꢀC(5’), 2 HꢀC(17’)); 1.50 – 1.55 (m, 2 HꢀC(3’)); 1.31 – 1.34 (m,
2 HꢀC(4’)); 0.92 (t, J ¼ 7.2, Me(18’)). 13C-NMR ((D6)DMSO): 173.4 (s, C(1’)); 132.1 (d, C(16’));
130.2, 130.1, 128.7, 128.6, 128.5, 128.4 (6d, C(6’), C(7’), C(9’), C(10’), C(12’), C(13’)); 127.5 (d, C(15’));
33.9 (t, C(2’)); 29.6 (t, C(4’)); 29.0 (t, C(5’)); 27.0, 25.8, 25.7 (3t, C(8’), C(11’), C(14’)); 24.6 (t, C(3’)); 20.6
(t, C(17’)); 14.7 (q, C(18’)). 1H- and 13C-NMR: Table 1. ESI-MS: 697 ([M þ Na]þ). HR-ESI-MS: 697.3413
([M þ Na]þ, C33H54NaO1þ4 ; calc. 697.3411).
Sarcoglycoside B (¼(2S)-3-(Hexadecyloxy)-2-hydroxypropyl b-d-Lyxofuranoside; 2): White amor-
phous powder. [a]D25 ¼ ꢀ41.2 (c ¼ 0.50, CHCl3). IR (KBr): 3393, 2920, 2851, 1467, 1143, 1073, 1005. H-
1
and 13C-NMR: Table 2. ESI-MS: 919 ([2M þ Na]þ), 471 ([M þ Na]þ), 449 ([M þ H]þ), 317, 299. HR-
ESI-MS: 471.3307 ([M þ Na]þ, C24H48NaO7þ ; calc. 471.3298).
Sarcoglycoside C (¼(2R)-3-(Hexadecyloxy)-2-hydroxypropyl b-d-Lyxofuranoside; 3): White amor-
phous powder. [a]D25 ¼ ꢀ58.5 (c ¼ 0.50, CHCl3). IR (KBr): 3393, 2920, 2851, 1467, 1143, 1073, 1005. 1H-
and 13C-NMR: Table 2. ESI-MS: 471 ([M þ Na]þ), 449 ([M þ H]þ), 317. HR-ESI-MS: 471.3280 ([M þ
Na]þ, C24H48NaOþ7 ; calc. 471.3298).
Methanolysis of 1. A soln. of 1 (7.5 mg) in anh. MeOH (1.5 ml) was treated with 3% MeONa/MeOH
(1.5 ml), and the mixture was stirred at r.t. for 1.5 h. The mixture was neutralized with positive-ion-
exchange resin and filtered, and the filtrate partitioned between CH2Cl2 and H2O. Evaporation of the
solvent from the CH2Cl2 phase yielded fatty acid methyl ester 1b (2.3 mg), which was identified by GC/
MS to be methyl octadeca-6,9,12,15-tetraenoate. The aq. phase was concentrated to give a residue, which
was purified by CC (Sephadex LH-20): (2R)-2,3-dihydroxypropyl 6-O-a-d-galactopyranosyl-b-d-
galactopyranoside (1; 3.6 mg).
Acid Hydrolysis of 2 and 3. A soln. of 2 (6 mg) in MeOH (1 ml) was added to 2m H2SO4 (1 ml) and
kept for 4 h at 1058 in a sealed ampule. The mixture was dried under N2 to remove MeOH and then
diluted with H2O (3.5 ml) and extracted with CH2Cl2 (3 ꢁ 7 ml). The org. layer was washed with H2O,
dried (Na2SO4), and concentrated to give a white amorphous powder, which was identified as 3-O-
hexadecyl-sn-glycerol (¼(2R)-3-(hexadecyloxy)propane-1,2-diol; 2.4 mg). The aq. phase was neutralized
with BaCO3, filtered, and concentrated to give a residue which was purified by CC (Sephadex LH-20,
MeOH) to furnish d-lyxose (1.1 mg).