- Synthesis of Bisdesmosidic Oleanolic Acid Saponins via a Glycosylation-Deprotection Sequence under Continuous Microfluidic/Batch Conditions
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We report the first synthesis of a series of bisdesmosidic oleanolic acid saponins using microflow reactor Comet X-01 via a continuous flow glycosylation-batch deprotection sequence. The main results of this study can be summarized as follows: (1) The microfluidic glycosylation of oleanolic acid at C-28 was achieved in quantitative yield and was applied to the synthesis of six C-28-monoglycosidic saponins. (2) The microfluidic glycosylation of oleanolic acid at C-3 was achieved in good yield without orthoester byproduct formation and was applied to the synthesis of three bisdesmosidic saponins. (3) The continuous synthesis of saponins via a microfluidic glycosylation-batch deprotection sequence was achieved in four steps involving two purifications. Thus, the continuous microfluidic glycosylation-deprotection process is expected to be suitable for the preparation of a library of bisdesmosidic oleanolic acid saponins for in vivo pharmacological studies.
- Konishi, Naruki,Shirahata, Tatsuya,Yokoyama, Masaki,Katsumi, Tatsuya,Ito, Yoshikazu,Hirata, Nozomu,Nishino, Takashi,Makino, Kazuishi,Sato, Noriko,Nagai, Takayuki,Kiyohara, Hiroaki,Yamada, Haruki,Kaji, Eisuke,Kobayashi, Yoshinori
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p. 6703 - 6719
(2017/07/15)
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- Synthesis and Evaluation of a Series of Oleanolic Acid Saponins as α-Glucosidase and α-Amylase Inhibitors
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Sixteen naturally occurring oleanolic acid saponins and their derivatives were synthesized in an efficient and practical strategy, and their inhibitory activities against α-glucosidase and α-amylase were evaluated in vitro. Among all the compounds, 28-O-m
- Guo, Tiantian,Wu, Shaoping,Guo, Sen,Bai, Lu,Liu, Qingchao,Bai, Naisheng
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p. 615 - 628
(2015/09/15)
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- New approaches to the structural modification of olean-type pentacylic triterpenes via microbial oxidation and glycosylation
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Microbial transformation of 4 olean-type pentacyclic triterpenes (OPTs), 3-oxo oleanolic acid (1), 3-acetyl oleanolic acid (2), oleanolic acid (3), and esculentoside A (4) was studied. After the screening of 12 strains of microbes, preparative biotransformation by two strains of Streptomyces griseus ATCC 13273 and Aspergillus ochraceus CICC 40330 resulted in the isolation of 10 metabolites. The microbial catalyzed high efficient regio-selective methyl oxidation and glycosylation were discovered, which could be provided as an alternative method to expand the structural diversity of OPTs. All the structures of the metabolites were elucidated unambiguously by ESI-MS, 1H NMR, 13C NMR, and 2D-NMR spectroscopy.
- Zhu, Yu-Yao,Qian, Li-Wu,Zhang, Jian,Liu, Ji-Hua,Yu, Bo-Yang
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experimental part
p. 4206 - 4211
(2011/07/08)
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- Biotransformation of oleanolic acid by Alternaria longipes and Penicillium adametzi
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Microbial transformation of oleanolic acid (1) was carried out. Six transformed products (2-7) from 1 by Alternaria longipes and three transformed products (8-10) from 1 by Penicillium adametzi were isolated. Their structures were elucidated as 2,3,19-trihydroxy-ursolic acid-28-O - d-glucopyranoside (2), 2,3,19-trihydroxy-ursolic acid-28-O - d-glucopyranoside (3), oleanolic acid 28-O - d-glucopyranosyl ester (4), oleanolic acid-3-O - d-glucopyranoside (5), 3-O-(-d-glucopyranosyl)-oleanolic acid-28-O - d-glucopyranoside (6), 2,3,19a-trihydroxy-oleanolic acid-28-O - d-glucopyranoside (7), 21-hydroxyl oleanolic acid-28-O - d-glucopyranoside (8), 21-hydroxyl oleanolic acid (9), and 7,21-dihydroxyl oleanolic acid (10) based on the extensive NMR studies. Among them, 10 was a new compound and compounds 5 and 8-10 had stronger cytotoxic activities against Hela cell lines than the substrate. At the same time, it was reported for the first time in this paper that the skeletons of compounds 2 and 3 were changed from oleanane to uranane and seven glycosidation products were obtained by biotransformation.
- Liu, Dai-Lin,Liu, Ying,Qiu, Feng,Gao, Ying,Zhang, Jing-Ze
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experimental part
p. 160 - 167
(2011/04/15)
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- USE OF URSOLIC ACID SAPONIN,OLEANOLIC ACID SAPONIN IN PREPARATION OF INCREASING LEUCOCYTES AND/OR PLATELET MEDICINE
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The invention provides the use of ursolic acid saponin and oleanolic acid saponin of formula (I) in preparing medicaments for increasing leucocytes and/or platelets. The invention also provides a pharmaceutical composition containing the same compound. The invention utilizes the cheap and accessible ursolic acid and oleanolic acid which are widely present in natural plants as raw materials, introduces monosaccharyls or oligosaccharyls by structural modification. It is proved by pharmacological tests that the compound of formula (I) have an activity of obviously increasing leucocytes and/or platelets.
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Page/Page column 6-7
(2010/08/08)
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- New cytotoxic saponin of Albizzia lebbeck
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The methanolic extract of the stem bark ofAlbizzia lebbeck, a new cytotoxic saponin is isolated and characterized with the help of FABMS, 13C NMR and chemical studies. The isolated compound exhibited potent cytotoxic activity against human aqueous cell carcinoma [HSC-2 and HSC-3].
- Jangwan,Dobhal, Maneesha,Kumar, Naveen
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experimental part
p. 123 - 126
(2010/06/12)
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- Glycoside modification of oleanolic acid derivatives as a novel class of anti-osteoclast formation agents
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Oleanolic acid, a natural product, possesses an anti-osteoclast formation activity. Targeting at discovery of novel and potent anti-bone resorption agents, 22 glycosides of oleanolic acid derivatives (including d-galactopyranosides, d-glucopyranosides, d-xylopyranoses, d-arabopyranoses and d-glycuronic acids) were synthesized at phase-transfer-catalyzed conditions (K2CO3, Bu4NBr, CH2Cl2-H2O) and their inhibitory activity on the formation of osteoclast-like multinucleated cells (OCLs) induced by 1α, 25-dihydroxy vitamin D3 was evaluated in a co-culture assay system. The structure-activity relationships of these compounds were also discussed.
- Li, Jun-Feng,Chen, Song-Jie,Zhao, Yu,Li, Jian-Xin
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experimental part
p. 599 - 605
(2009/05/27)
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- Naturally occurring pentacyclic triterpenes as inhibitors of glycogen phosphorylase: Synthesis, structure-activity relationships, and X-ray crystallographic studies
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Twenty-five naturally occurring pentacyclic triterpenes, 15 of which were synthesized in this study, were biologically evaluated as inhibitors of rabbit muscle glycogen phosphorylase a (GPa). From SAR studies, the presence of a sugar moiety in triterpene saponins resulted in a markedly decreased activity (7, 18-20) or no activity (21, 22). These saponins, however, might find their value as potential natural prodrugs which are much more water-soluble than their corresponding aglycones. To elucidate the mechanism of GP inhibition, we have determined the crystal structures of the GPb-asiatic acid and GPb-maslinic acid complexes. The X-ray analysis indicates that the inhibitors bind at the allosteric activator site, where the physiological activator AMP binds. Pentacyclic triterpenes represent a promising class of multiple-target antidiabetic agents that exert hypoglycemic effects, at least in part, through GP inhibition.
- Wen, Xiaoan,Sun, Hongbin,Liu, Jun,Cheng, Keguang,Zhang, Pu,Zhang, Liying,Hao, Jia,Zhang, Luyong,Ni, Peizhou,Zographos, Spyros E.,Leonidas, Demettes D.,Alexacou, Kyra-Melinda,Gimisis, Thanasis,Hayes, Joseph M.,Oikonomakos, Nikos G.
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experimental part
p. 3540 - 3554
(2009/04/07)
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- BETAVULGAROSIDES I, II, II, IV, AND V, HYPOGLYCEMIC GLUCURONIDE SAPONINS FROM THE ROOTS AND LEAVES OF BETA VULGARIS L. (SUGAR BEET)
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Five glucuronide saponins named betavulgarosides I, II, III, IV, and V were isolated from the roots and leaves of Beta vulgaris L. (Sugar beet).Their structures were elucidated on the basis of chemical and physicochemical evidence.Betavulgarosides II, III, and IV and the prosapogenol (6) were found to exhibit hypoglycemic effect on oral glucose tolerance test in rats.
- Yoshikawa, Masayuki,Murakami, Toshiyuki,Kadoya, Masashi,Matsuda, Hisashi,Yamahara, Johji,et al.
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p. 1621 - 1626
(2007/10/03)
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- Glycosylation of Acids under Phase Transfer Conditions. Partial Synthesis of Saponins.
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β-D-glycosyl esters are prepared in high yields by reaction of various carboxylic acids and acetobromosugars.The reaction uses potassium carbonate under phase transfer conditions.Deacetylation affords the β-D-glycosylcarboxylates.
- Bliard, Christophe,Massiot, Georges,Nazabadioko, Serge
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p. 6107 - 6108
(2007/10/02)
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