- Synthesis of novel diosgenyl saponin analogs and evaluation effects of rhamnose moeity on their cytotoxic activity
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Diosgenyl saponins, as a type of natural products derived from plants, are the main active component of traditional chinese medicine. Inspiringly, a large number of natural diosgensyl saponins have been shown to exert excellent toxicity to hepatocellular cancer (HCC) cells. In order to better understand the relationship between the structures and their biological effects, a group of diosgenyl saponins (1–4 as natural products and 5 and 6 as their analogs) were efficiently synthesized. The cytotoxic activity of these compounds was evaluated on human hepatocellular carcinoma (HepG2) cells. Structure–activity relationship studies showed that the pentasaccharide or hexasaccharide saponin analogs were relatively less active than their corresponding disaccharide analogue or dioscin. The extension of 4-branched rhamnose moiety on these saponin does not exhibit significant effect on their cytotoxic activity, which disclosed that a certain number and the linkage mode of rhamnose moieties could influence the cytotoxicity of steroid saponins on HepG2 cells.
- Meng, Xin,Pan, Yiwu,Liu, Tao,Luo, Chen,Man, Shuli,Zhang, Yongmin,Zhang, Yan
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- Synthesis of spirostanol saponins via gold(I)-catalyzed glycosylation in the presence of Ga(OTf)3, In(OTf)3, or HOTf
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An effective approach relying on a Lewis acid- or Br?nsted acid-assisted gold(I)-catalyzed glycosylation has been reported in the synthesis of a panel of the representative natural spirostanol saponins, namely polyphyllin D (1), polyphyllin V (2), dioscin (3), formosanin C (4), and a derivative of polyphyllin D bearing a terminal azide group (5). This approach highlights the engagement of low loadings of Ph3AuPOTf (≤ 0.5 mol%) in the presence of Ga(OTf)3, In(OTf)3, or HOTf (~10mol%) as a co-catalyst, at practical reaction rates as an alternative to the conventional ~10 mol% loadings of the gold(I) catalyst in the glycosylation. Polyphyllin D (1) was obtained in 41% overall yield over six steps compared to the maximum 30% yield in previous syntheses where conventional donors and promoters were used. By exploiting a regioselective rhamnosylation, a “one-pot” approach was adopted to assemble 1 and 5, thus further strengthening the efficiency of the gold(I)-catalyzed glycosylation.
- Ehianeta, Teddy Stephen,Shen, Dacheng,Xu, Peng,Yu, Biao
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supporting information
p. 827 - 833
(2019/07/22)
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- Synthesis of a group of diosgenyl saponins with combined use of glycosyl trichloroacetimidate and thioglycoside donors
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With the combined use of glycosyl trichloroacetimidates and thioglycosides, a group of natural diosgenyl saponins (1-6) are efficiently synthesized, in either a stepwise or a 'one-pot' manner. The trichloroacetimidate is employed as an efficient temporary hydroxy protecting group in glycosylation with the glycosyl trichloroacetimidate. The intermolecular alkylthio-group transfer is demonstrated to be a common side-reaction during glycosylation with thioglycosides. The Royal Society of Chemistry 2000.
- Yu, Hai,Yu, Biao,Wu, Xiangyang,Hui, Yongzheng,Han, Xiuwen
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p. 1445 - 1453
(2007/10/03)
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- Synthesis of a group of diosgenyl saponins by a one-pot sequential glycosylation
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A group of natural diosgenyl saponins was synthesized in a highly efficient manner employing the 'one-pot sequential glycosylation' protocol with the combined use of glycosyl trichloroacetimidates and thioglycosides.
- Yu, Biao,Yu, Hai,Hui, Yongzheng,Han, Xiuwen
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p. 8591 - 8594
(2007/10/03)
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- Studies on the constituents of palmae plants. VI. Steroid saponins and flavonoids of leaves of Phoenix canariensis hort. ex CHABAUD, P. humilis ROYLE var. hanceana BECC., P. dactylifera L., and Licuala spinosa WURMB.
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Steroid saponins and flavonoids of the leaves of Phoenix canariensis hort. ex CHABAUD, P. humilis ROYLE var. hanceana BECC., P. dactylifera L., and Licuala spinosa WURMB. have been investigated. Tricin 7-O-β-D-glucopyranoside (1), isorhamnetin 3-O-β-D-glucopyranoside (2), isoquercitrin (3), isorhamnetin 3-O-β-rutinoside (4), rutin (5), and methyl (25S)-proto-Pb (6) from P. canariensis, 1, 6, glucoluteolin (7), tricin 7-O-α-L-rhamnopyranosyl(1→2)-β-D-glucopyranoside (8), and methyl (25S)-proto-loureiroside (9) from P. humilis var. hanceana, 1, 2, 8, methyl proto-prosapogenin A of dioscin (10), methyl proto-reclinatoside (11) and methyl proto-Pb (12) from P. dactylifera, and vitexin (13) and methyl (25S)-proto-dioscin (14) from Licuala spinosa have been isolated and identified.
- Asami,Hirai,Shoji
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p. 2053 - 2056
(2007/10/02)
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- Studies on the Constituents of Palmae Plants. II. The Constituents of Rhapis exelsa Henry and R. humilis Bl.
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Further studies have been done on the constituents of the stems, underground parts and leaves of two Palmae plants, Rhapis exelsa Henry and R. humilis Bl.We isolated and identified dioscin, Pb, deltonin, methyl proto-dioscin, methyl proto-Pb and methyl proto-deltonin from the stems, dioscin, methyl proto-dioscin and methyl proto-Pb from the underground parts, and saponaretin (= isovitexin), methyl proto-dioscin, methyl proto-Pb and methyl proto-rhapissaponin from the leaves of R. exelsa.On the other hand we isolated and identified prosapogenin A of dioscin, dioscin, deltonin, methyl proto-prosapogenin A of dioscin, methyl proto-dioscin and methyl proto-deltonin from the stems, dioscin, methyl proto-prosapogenin A of dioscin, methyl proto-dioscin and methyl proto-Pb from the underground parts, and saponaretin, vitexin, isoorientin, methyl proto-prosapogenin A of dioscin, methyl proto-dioscin and methyl proto-Pb from the leaves of R. humilis.Methyl proto-rhapissaponin is a new furostanol saponin and its structure has been established to be 26-O-β-D-glucopyranosyl 22-O-methyl-25(R)-furost-5-en-3β,22,26-triol 3-O-4)-α-L-rhamnopyranosyl(1->4)-α-L-rhamnopyranosyl(1->4)>-2)>-β-D-glucopyranoside.This is the second report of the isolation of steroidal saponins from Palmae plants, and the results are interesting from the standpoint of chemotaxonomy. Keywords - Rhapis exelsa; Rhapis humilis; Palmae; steroidal saponin; furostanol oligoside; diosgenin; flavone glycoside; flavone C-glycoside; methyl proto-rhapissaponin
- Hirai, Yasuaki,Sanada, Shuichi,Ida, Yoshiteru,Shoji, Junzo
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p. 4003 - 4011
(2007/10/02)
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