- Indiosides G-K: Steroidal glycosides with cytotoxic and anti-inflammatory activities from Solanum violaceum
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Five new steroidal glycosides (1-5) and nine known compounds were isolated from Solanum violaceum. Indiosides G (1) and H (2) are spirostene saponins with an iso-type F ring, indioside I (3) is a spirostane saponin, and indiosides J (4) and K (5) are unusual furostanol saponins with a deformed F ring. These structures represent rare naturally occurring steroidal skeletons. The structures of the new compounds were elucidated using 1D and 2D spectroscopic techniques and acid hydrolysis. Compounds 2, 3, and 7-9 exhibited cytotoxic activity against six human cancer cell lines (HepG2, Hep3B, A549, Ca9-22, MDA-MB-231, and MCF-7) with IC50 values of 1.83-8.04 μg/mL. Steroidal saponins 3, 8, and 9 showed inhibitory effects on superoxide anion generation with IC50 values of 2.84 ± 0.18, 0.62 ± 0.03, and 1.62 ± 0.59 μg/mL, respectively. Saponins 8 and 9 also inhibited elastase release with IC50 values of 111.05 ± 7.37 and 4.04 ± 0.51 μg/mL, respectively. Structure-activity relationship correlations of these compounds with respect to cytotoxic and anti-inflammatory effects are discussed.
- Yen, Chiao-Ting,Lee, Chia-Lin,Chang, Fang-Rong,Hwang, Tsong-Long,Yen, Hsin-Fu,Chen, Chao-Jung,Chen, Shu-Li,Wu, Yang-Chang
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experimental part
p. 636 - 643
(2012/06/30)
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- Tandem epoxidation-alcoholysis or epoxidation-hydrolysis of glycals catalyzed by titanium(IV) isopropoxide or Venturello's phosphotungstate complex
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Venturello's phosphotungstate complex and titanium(IV) isopropoxide [Ti(O-i-Pr)4] were successfully used as catalysts for the epoxidation-alcoholysis of glycals using hydrogen peroxide [H2O 2]. Reaction substrates included a range of variously protected glycals and different alcohols were used as solvents. Ti(O-i-Pr)4 was only effective in methanol as solvent, but gave methyl glycosides in high yields and high selectivities. The Venturello complex proved to be a very versatile and efficient catalyst. Apart from epoxidation-alcoholysis in alcoholic solvents it also showed activity in biphasic conditions to allow for glycosylation of long-chain alcohols and was very effective in the stereoselective dihydroxylation of benzylated glucal.
- Levecque, Pieter,Gammon, David W.,Kinfe, Henok Hadgu,Jacobs, Pierre,De Vos, Dirk,Sels, Bert
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supporting information; experimental part
p. 1557 - 1568
(2009/07/10)
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- C-GLYCOSIDE ANALOGUES OF N-(4-HYDROXYPHENYL)RETINAMIDE-O-GLUCURONIDE
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The present invention provides breast cancer chemopreventive arylamide analogues of retinoic acid, more particularly C-glycoside analogues of N-(4-hydroxyphenyl)retinamide-O-glucuronide and N-glycoside analogue of retinoyl beta-glucuronide that resist both beta-glucuronidase mediated enzymatic hydrolysis as well as acid catalyzed hydrolysis. Specifically, the drugs include 4-(retinamido)phenyl-C-glucuronide; 4-(retinamido)phenyl-C-glucoside; 4-(retinamido)benzyl-C-xyloside; 4-(retinamido)benzyl-C-glucoside; 4-(retinamido)benzyl-C-glucuronide; 4-(retinamido)phenyl-C-xyloside, 1-(B-D-lucopyranosyl) retinamide and 1-(D-glucopyranosyluronosly) retinamide. The invention also relates to a method for making such drugs.
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- PYRIDINDOLOL ANALOGUES. SYHTHESIS OF 3-HYDROXYMETHYL-1-(POLYHYDROXYALKYL)-β-CARBOLINES
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Peracetylated (D)-glucose, (D)-galactose, (D)-ribose, (L)-arabinose and (D)-xylose have been subjected to a Pictet-Spengler cyclisation with methyl tryptophanate to give β-carboline derivatives which have been converted to a series of pyridindolol analogues.
- Willard, Nico P.,Dorland, Erwin,Pandit, Upendra K.
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p. 1549 - 1556
(2007/10/02)
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