- Medicinal plants of Thailand. I structures of rheedeiosides A-D and cis-entadamide A β-D-glucopyranoside from the seed kernels of Entada rheedei
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Four new oleanane-type triterpene oligoglycosides, named rheedeiosides A, B, C and D, and one new thioamide glycoside, cis-entadamide A β-D-glucopyranoside, were isolated from the seed kernels of a Thai medicinal plant, Entada rheedei SPRENGEL. The rheedeiosides were found to contain N-acetylglucosamine as a sugar component. Their structures were elucidated based on spectral and chemical evidence.
- Sugimoto, Sachiko,Matsunami, Katsuyoshi,Otsuka, Hideaki
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experimental part
p. 466 - 471
(2011/06/19)
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- Echinocystic acid 3,16-O-bisglycosides from Albizia procera
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Three triterpene glycosides and two known ones were isolated from the bark of Albizia procera by using chromatographic techniques. The structures of the compounds were determined to be 3-O-β-d-xylopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β-d- glucopyranosyl echinocystic acid 16-O-β-d-glucopyranoside, 3-O-β-d-xylopyranosyl-(1 → 2)-α-l-arabinopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β-d-glucopyranosyl echinocystic acid 16-O-β-d-glucopyranoside and 3-O-α-l-arabinopyranosyl-(1 → 2)-α-l-arabinopyranosyl-(1 → 6)-2-acetamido-2-deoxy-β-d- glucopyranosyl echinocystic acid 16-O-β-d-glucopyranoside. Their structures were determined by NMR techniques including HOHAHA, 1H-1H COSY, ROE, HMQC and HMBC experiments together with FABMS as well as acid hydrolysis. To the best of our knowledge, the new compounds are considered the first examples of echinocystic acid 3,16-O-bisglycosides. In contrast to other cytotoxic echinocystic acid glycosides with N-acetyl glucosamine unit, the new glycosides were found inactive when assayed by MTT method for their cytotoxicities against the human tumor cell lines HEPG2, A549, HT29 and MCF7. The results showed the importance of the free hydroxyl group at the aglycone C-16 for exhibiting cytotoxic properties.
- Miyase, Toshio,Melek,Ghaly,Warashina, Tsutomu,El-Kady,Nabil, Marian
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experimental part
p. 1375 - 1380
(2011/05/17)
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