5 research outputs found
Catalytic Asymmetric Peroxidation of α,β-Unsaturated Nitroalkenes by a Bifunctional Organic Catalyst
A new
enantioselective peroxidation of α,β-unsaturated
nitroalkenes was realized with an easily accessible acid–base
bifunctional organic catalyst derived from cinchona alkaloids. This
reaction provides unprecedented easy access to optically active chiral
peroxides, as illustrated by the asymmetric synthesis of β-peroxy
nitro compounds
Catalytic Enantioselective Peroxidation of α,β-Unsaturated Aldehydes for the Asymmetric Synthesis of Biologically Important Chiral Endoperoxides
We have developed
an unprecedented highly enantioselective catalytic
peroxidation of enals. Critical to this development is the discovery
that varying the structure of the hydroperoxide has a significant
impact on the enantioselectivity of the organocatalytic asymmetric
peroxidation. This novel transformation enabled the development of
an enantioselective route toward the core structure shared by all
members of the stolonoxide family of anticancer natural products,
a connected <i>trans</i>-3,6-disubstituted-1,2-dioxane and <i>trans</i>-2,5-disubstituted-tetrahydrofuran ring system. Our
route also features an unprecedented cyclization cascade of a chiral
bis(epoxy)hydroperoxide. The new methodology and synthetic strategy
established in this work should be applicable to the enantioselective
synthesis of a broad range of chiral 1,2-dioxolanes and 1,2-dioxanes,
thereby facilitating biological and medicinal chemistry studies of
peroxy natural products
A Vancomycin-Templated DNA-Encoded Library for Combating Drug-Resistant Bacteria
It is an urgent need to tackle the global crisis of multidrug-resistant
bacterial infections. We report here an innovative strategy for large-scale
screening of new antibacterial agents using a whole bacteria-based
DNA-encoded library (DEL) of vancomycin derivatives via peripheral
modifications. A bacterial binding affinity assay was established
to select the modification fragments in high-affinity compounds. The
optimal resynthesized derivatives demonstrated excellently enhanced
activity against various resistant bacterial strains and provided
useful structures for vancomycin derivatization. This work presents
the new concept in a natural product-templated DEL and in antibiotic
discovery through bacterial affinity screening, which promotes the
fight against drug-resistant bacteria
A Vancomycin-Templated DNA-Encoded Library for Combating Drug-Resistant Bacteria
It is an urgent need to tackle the global crisis of multidrug-resistant
bacterial infections. We report here an innovative strategy for large-scale
screening of new antibacterial agents using a whole bacteria-based
DNA-encoded library (DEL) of vancomycin derivatives via peripheral
modifications. A bacterial binding affinity assay was established
to select the modification fragments in high-affinity compounds. The
optimal resynthesized derivatives demonstrated excellently enhanced
activity against various resistant bacterial strains and provided
useful structures for vancomycin derivatization. This work presents
the new concept in a natural product-templated DEL and in antibiotic
discovery through bacterial affinity screening, which promotes the
fight against drug-resistant bacteria
In Vivo Study of the Efficacy of the Essential Oil of <i>Zanthoxylum bungeanum</i> Pericarp in Dextran Sulfate Sodium-Induced Murine Experimental Colitis
The
purpose of this study was to investigate the protective effects
and mechanisms of the essential oil of <i>Zanthoxylum bungeanum</i> pericarp (ZBEO) on dextran sulfate sodium (DSS)-induced experimental
colitis in mice. ZBEO decreased DSS-induced body weight loss, the
disease activity index, colon length shortening, colonic pathological
damage, and myeloperoxidase activities. The production of pro-inflammatory
mediators was significantly alleviated by ZBEO. Further mechanistic
analysis showed that ZBEO inhibited inflammation by regulating NF-κB
and PPARγ pathways. ZBEO also inhibited NLRP3 activation in
colitis in mice. Furthermore, ZBEO contributed to the maintenance
of tight junction architecture by regulating the expression of zonula
occludens-1 during colitis. Surprisingly, treatment with ZBEO increased
levels of the commensal bacteria containing <i>Lactobacillus</i> and <i>Bifidobacteria</i> but reduced <i>Escherichia
coli</i> levels in the feces of mice. These results suggested
that supplementation with ZBEO might provide a new dietary strategy
for the prevention of ulcerative colitis