53942-46-4Relevant articles and documents
Acetylated chitosan oligosaccharides act as antagonists against glutamate-induced PC12 cell death via Bcl-2/Bax signal pathway
Hao, Cui,Gao, Lixia,Zhang, Yiran,Wang, Wei,Yu, Guangli,Guan, Huashi,Zhang, Lijuan,Li, Chunxia
, p. 1267 - 1289 (2015)
Chitosan oligosaccharides (COSs), depolymerized products of chitosan composed of β-(1→4) D-glucosamine units, have broad range of biological activities such as antitumour, antifungal, and antioxidant activities. In this study, peracetylated chitosan oligosaccharides (PACOs) and N-acetylated chitosan oligosaccharides (NACOs) were prepared from the COSs by chemcal modification. The structures of these monomers were identified using NMR and ESI-MS spectra. Their antagonist effects against glutamate-induced PC12 cell death were investigated. The results showed that pretreatment of PC12 cells with the PACOs markedly inhibited glutamate-induced cell death in a concentration-dependent manner. The PACOs were better glutamate antagonists compared to the COSs and the NACOs, suggesting the peracetylation is essential for the neuroprotective effects of chitosan oligosaccharides. In addition, the PACOs pretreatment significantly reduced lactate dehydrogenase release and reactive oxygen species production. It also attenuated the loss of mitochondrial membrane potential. Further studies indicated that the PACOs inhibited glutamate-induced cell death by preventing apoptosis through depressing the elevation of Bax/Bcl-2 ratio and caspase-3 activation. These results suggest that PACOs might be promising antagonists against glutamate-induced neural cell death.
Synthesis of chitotetraose and chitohexaose based on dimethylmaleoyl protection
Aly, Mohamed R.E,Ibrahim, El-Sayed I,El Ashry, El Sayed H,Schmidt, Richard R
, p. 129 - 142 (2007/10/03)
tert-Butyldimethylsilyl 3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-β-D-glucopyranoside was readily transformed into the disaccharide glycosyl donor, 3,4,6-tri-O-acetyl-2-deoxy-2-dimethylmaleimido-β-D-glucopyranosyl- (1→4)-3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-α/β-D- glucopyranosyl trichloroacetimidate, and the disaccharide glycosyl acceptor, tert-butyldimethylsilyl 3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-β-D-glucopyranosyl- (1→4)-3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-β-D- glucopyranoside. A TMSOTf-catalysed coupling of the acceptor with the donor afforded the respective tetrasaccharide derivative, which can be transformed to chitotetraose. tert-Butyldimethylsilyl 3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-4-O-phenoxyacetyl-β-D- glucopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido- β-D-glucopyranoside was converted into donor 3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-4-O-phenoxyacetyl-β-D- glucopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido- β-D-glucopyranosyl trichloroacetimidate. Its coupling with benzyl 3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-β-D-glucopyranosyl- (1→4)-3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-β-D- glucopyranoside, followed by dephenoxyacetylation, gave benzyl 3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-β-D-glucopyranosyl- (1→4)-3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido-β-D- glucopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2-dimethylmaleimido- β-D-glucopyranosyl-(1→4)-3,6-di-O-benzyl-2-deoxy-2- dimethylmaleimido-β-D-glucopyranoside, whose glycosylation furnished, after replacement of the DMM-group by the acetyl moiety and subsequent deprotection, chitohexaose.
