Chem. Pharm. Bull. 55(3) 435—441 (2007)

constituents from Chinese natural medicines, we have reported the isolation and absolute stereostructure elucidation of two megastigmanes, sarmentoic acid and sarmentol A, and six megastigmane glycosides, sedumosides A1, A2, A3, B, C, and D, from the whole plant of Sedum sarmentosum (Crassulaceae) together with eight known megastigmane constituents. As a continuation of the characterization studies on S. sarmantosum, we have isolated six new megastigmane glycosides, sedumosides E1 (1), E2 (2), E3 (3), F1 (4), F2 (5), and G (6), from this herbal medicine together with 33 known compounds (7—39). In this paper, we describe the isolation and absolute stereostructure elucidation of these new megastigmane glycosides (1—6). The hot water extract from the whole plant of S. sarmentosum was treated with methanol to give the methanol-soluble part (0.57% from the fresh plant). The methanol-soluble part was subjected to Diaion HP-20 column chromatography (H2O→MeOH) to give the waterand methanol-eluted fractions (0.44 and 0.13%, respectively) as previously reported. The methanol-eluted fraction was subjected to normaland reversed-phase silica gel column chromatographies, and finally HPLC to give 1 (0.00005%), 2 (0.00018%), 3 (0.00001%), 4 (0.00015%), 5 (0.00018%), 6 (0.00001%), ( )-pinoresinol 4,4 -di-O-b-D-glucopyranoside (7, 0.00005%), ( )-isolariciresinol (8, 0.00012%), woorenoside XI (9, 0.00015%), ( )-isolariciresinol 3a-O-b-D-glucopyranoside (10, 0.00003%), secoisolariciresinol (11, 0.00010%), 12 (0.00005%), ( )-lariciresinol 4-O-b-D-glucopyranoside (13, 0.00007%), ( )-lariciresinol 4,4 -bis-Ob-D-glucopyranoside (14, 0.00031%), apigenin 7-O-b-Dglucopyranoside (15, 0.00005%), luteolin 7-O-b-D-glucopyranoside (16, 0.00006%), tricin 7-O-b-D-glucopyranoside (17, 0.00002%), kaempferol 7-O-b-D-glucopyranoside (18, 0.00004%), 19 (0.00015%), grosvenorine (20, 0.00010%), quercetin 3,7-di-O-a-Lrhamnopyranoside (21, 0.00007%), 22 (0.00004%), isorhamnetin 7-O-b-D-glucopyranoside (23, 0.00009%), 24 (0.00005%), isorhamnetin 3,7-di-O-b-D-glucopyranoside (25, 0.00014%), 26 (0.00005%), herbacetin 8-methyl ester 3,7-di-O-b-D-glucopyranoside (27, 0.00003%), limocitrin 3-O-b-D-glucopyranoside (28, 0.00008%), limocitrin 3,7-di-O-b-D-glucopyranoside (29, 0.00057%), 2-phenylethyl b-D-glucopyranoside (30, 0.00001%), 2-phenylethyl D-rutinoside (31, 0.00003%), eugenyl b-D-glucopyranoside (32, 0.00007%), 4R-pmenth-1-ene-7,8-diol 7-O-b-D-glucopyranoside (33, 0.00006%), 4R-p-menth-1-ene-7,8-diol 8-O-b-D-glucopyranoside (34, 0.00004%), (R)-a-terpinyl b-D-glucopyranoside (35, 0.00012%), octa-1-en-3-yl a-L-rhamnopyranosyl(1→6)-b-D-glucopyranoside (36, 0.00043%), 1-acetyl b-carboline (37, 0.00001%), 38 (0.00003%), and 39 (0.00005%). Absolute Stereostructures of Sedumosides E1 (1), E2 (2), E3 (3), F1 (4), F2 (5), and G (6) Sedumoside E1 (1) was isolated as an amorphous powder with negative optical rotation ([a]D 33.9° in MeOH). The IR spectrum of 1 showed absorption bands at 3431, 1081, and 1046 cm 1 ascribable to hydroxyl and ether functions. In the positive-ion fast atom bombardment (FAB)-MS of 1, a quasimolecular ion peak was observed at m/z 545 (M Na) . The molecular formula C25H46O11 of 1 was determined by high-resolution Bioactive Constituents from Chinese Natural Medicines. XXII. Absolute Structures of New Megastigmane Glycosides, Sedumosides E1, E2, E3, F1, F2, and G, from Sedum sarmentosum (Crassulaceae) Toshio MORIKAWA, Yi ZHANG, Seikou NAKAMURA, Hisashi MATSUDA, Osamu MURAOKA, and Masayuki YOSHIKAWA*