Insufficient endogenous neurotrophin supply contributes to neurodegeneration. Meanwhile, neuronal injuries are also attributed to oxidative stress upon toxin exposure. Thus, reconstruction neurite extension and antioxidative stress are the potential strategies for ameliorating neuronal injuries. However, there is no well-defined therapeutic developed in this regard. In search of such therapeutics, Petrosiol E is identified here as a potent inducer to guide the differentiation of neuronal progenitor cells. Petrosiol E also considerably promotes embryonic stem cell differentiation into neural ectoderm features. Moreover, Petrosiol E reveals an antioxidant function to protect cells from oxidative stress induced by arsenic. Moreover, the molecular mechanism underlying Petrosiol E-induced neuronal differentiation is uncovered: (a) enhancement of NF-E2-related factor 2 (Nrf 2) activity in driving neuronal differentiation; (b) diminishment of oxidative stress. Petrosiol E activates the mitogen-activated protein kinase and serine/threonine kinase signaling to enhance the activity of Nrf 2. As a result of enhanced Nrf 2 activity, neuronal differentiation is accelerated, and the cellular antioxidation responses are also enforced, even under arsenic-induced neurotoxicity. Together, the combined results unveil a desirable role of Petrosiol E in driving neuronal differentiation and in combating oxidative stress. This study would open an avenue to develop new therapeutics based on Petrosiol compounds to treat neurodegenerative diseases.
NKT cells, a unique subset of T cells that recognizes glycolipid antigens presented by CD1d molecules, are believed to produce key cytokines of both Th1 and Th2 T cells and are thus involved in the control of several types of immune response. As an active glycolipid antigen having α-galactosyl ceramide core structure, KRN7000 showed promising immunostimulation activity and was selected as an anticancer drug candidate for further clinical application. In this report, three new KRN7000 structural analogues were designed and synthesized, in which the ring oxygen of the galactopyranose residue is replaced by a sulfur atom along with the variation on the lipid chain. Their abilities for stimulating mouse NKT cells to produce IFN-γ and IL-4 were evaluated both in vivo and in vitro.
A convenient method has been developed for regioselective anomeric deacylation of carbohydrate derivatives using FeCl(3)center dot 6H(2)O in CH(3)CN. Operational simplicity, economic consideration, high yield, and low toxicity are key features associated with this protocol. (C) 2008 Elsevier Ltd. All rights reserved.
Regio- and stereoselective synthesis of furanosyl oligosaccharides in moderate to very good yields using arabinofuranosyl trichloroacetimidates as glycosyl donors and unprotected or partially protected glycosides as acceptors was described. A convergent synthesis of 1 → 5-linked α-l-arabinofuranosyl octamer was presented.
Two oligosaccharide derivatives, β-d-Glcp-(1−6)-β-d-Glcp-(1−6)-β-d-Glcp-(1−6)-β-d-Glcp-(1−4)-α-d-ManpOMe (1) and β-d-Glcp-(1−6)-β-d-Glcp-(1−6)-β-d-Glcp-(1−6) -β-d-Glcp-(1−6)-β-d-Glcp-(1−6)-β-d-Glcp-(1−4)-α-d-ManpOMe (2), have been synthesized efficiently using a convergent glycosylation strategy of 2 + 3 and 2 + 5. 1,6-Anhydro-β-d-glucopyranose, which was prepared from cotton pyrolysis, was applied as a key synthon in the synthesis, significantly simplifying the preparation. The bioassay suggested that these two oligosaccharides can both stimulate the growth of maize cultured in liquid medium at a concentration of 3 ppm.
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