77-95-2Relevant articles and documents
Eucommicin A, a β-truxinate lignan from Eucommia ulmoides, is a selective inhibitor of cancer stem cells
Fujiwara, Ayaka,Nishi, Mayuko,Yoshida, Shigeo,Hasegawa, Morifumi,Yasuma, Chieko,Ryo, Akihide,Suzuki, Yoshihito
, p. 139 - 145 (2016)
Cancer stem cells (CSCs) constitute a small population of undifferentiated cells within a tumor that have the ability to self-renew and drive tumor formation, thus behaving as cancer-initiating cancer cells. Therapeutic interventions that eliminate CSCs are necessary to completely cure patients, since CSCs are a crucial source of tumor recurrence and metastasis. An induced CSC-like (iCSCL) model was recently established using induced pluripotent stem cells (iPSCs). In this study, a natural product - eucommicin A - was identified from Eucommia ulmoides leaves by screening for anti-CSC activity using the iCSCL model. Its structure was elucidated by spectroscopic methods as a quinic acid diester of 3,4,3′,4′-tetrahydroxy-β-truxinic acid. Eucommicin A exhibited selective anti-CSC activity and inhibited tumor sphere formation by iCSCL cells. The results of this study suggest that eucommicin A could serve as a lead compound in the development of drugs to abrogate the stemness and self-renewal ability of CSCs.
SEVEN QUINIC ACID GALLATES FROM QUERCUS STENOPHYLLA
Nishimura, Hiroaki,Nonaka, Gen-Ichiro,Nishioka, Itsuo
, p. 2621 - 2624 (1984)
A chemical investigation of the bark of Quercus stenophylla has led to the isolation and characterization of all of the possible structural isomers of quinic acid gallates; 3-O-, 4-O-, 5-O-, 3,4-di-O-, 3,5-di-O-, 4,5-di-O- and 3,4,5-tri-O-galloylquinic acids.Evidence for the structures of these compounds was obtained from analysis of the 1H and 13C NMR spectra, and hydrolytic studies.Key Word Index - Quercus stenophylla; Fagaceae; quinic acid gallates; gallotannins; tannase.
Analysis of protein-phenolic compound modifications using electrochemistry coupled to mass spectrometry
Kallinich, Constanze,Schefer, Simone,Rohn, Sascha
, (2018/02/07)
In the last decade, electrochemical oxidation coupled with mass spectrometry has been successfully used for the analysis of metabolic studies. The application focused in this study was to investigate the redox potential of different phenolic compounds such as the very prominent chlorogenic acid. Further, EC/ESI-MS was used as preparation technique for analyzing adduct formation between electrochemically oxidized phenolic compounds and food proteins, e.g., alpha-lactalbumin or peptides derived from a tryptic digestion. In the first step of this approach, two reactant solutions are combined and mixed: one contains the solution of the digested protein, and the other contains the phenolic compound of interest, which was, prior to the mixing process, electrochemically transformed to several oxidation products using a boron-doped diamond working electrode. As a result, a Michael-type addition led to covalent binding of the activated phenolic compounds to reactive protein/peptide side chains. In a follow-up approach, the reaction mix was further separated chromatographically and finally detected using ESI-HRMS. Compound-specific, electrochemical oxidation of phenolic acids was performed successfully, and various oxidation and reaction products with proteins/peptides were observed. Further optimization of the reaction (conditions) is required, as well as structural elucidation concerning the final adducts, which can be phenolic compound oligomers, but even more interestingly, quite complex mixtures of proteins and oxidation products.
A novel stereoselective synthesis of (-)-quinic acid starting from the naturally abundant (-)-shikimic acid
Zhang, Wei,Zhu, Xing-Liang,Ding, Wei,Shi, Xiao-Xin
, p. 1375 - 1381 (2015/11/25)
A new stereoselective synthesis of (-)-quinic acid from the naturally abundant (-)-shikimic acid is described. Ethyl shikimate 2 was first prepared in 97% yield via esterification of (-)-shikimic acid according to a previous report. Ester 2 was then transformed into an epimeric mixture of 3,4-O-benzylidene shikimate 3, which was directly converted into compound 4 in 90% yield (over 2 steps from ester 2) via an NBS-mediated acetal ring-opening reaction. Acetylization of the hydroxyl group at the C-5 position of compound 4 gave compound 5 in 98% yield. Compound 5 was transformed into compound 6 in 91% yield via a highly stereoselective Ru-catalyzed dihydroxylation. Subsequently, compound 6 was converted into epoxide 7 in 82% yield via an intramolecular SN2 type substitution. A regioselective epoxide-opening of compound 7 by PPh3-I2 complex furnished an iodo compound 8 in 79% yield. Removal of the iodine atom in compound 8 by Pd/C-catalyzed hydrogenation produced compound 9 in 92% yield. Methanolysis of compound 9 gave methyl quinate 10 in 92% yield. Finally, hydrolysis of compound 10 afforded the targeted compound (-)-quinic acid 1 in 90% yield. The title compound (-)-quinic acid 1 was stereoselectively synthesized through 10 steps starting from (-)-shikimic acid in 38% overall yield.