The potent radioprotective agents: Novel nitronyl nitroxide radical spin-labeled resveratrol derivatives.

It is commonly known that radiotherapy is still a key modality for treatment of cancer. Though this effect is desirable during radiotherapy, it leads to radiotoxicity on normal healthy cells. In the present research, we designed, synthesized and analyzed a series of nitronyl nitroxide radical (NITR) spin-labeled resveratrol (RES) derivatives. The cytotoxicity of the newly synthesized substances was tested on Jurkat T cells. The derivatives were studied as reactive oxygen species (ROS) scavenger to protect ionizing radiation of Jurkat T cells upon 6 Gy X-irradiation. The experimental results revealed that compound 2 and 3 could significantly alleviate the damage of Jurkat T cells, as evidenced by decreasing ROS production and restoring the cell apoptosis. Further mechanism investigations indicated that the radioprotective effects of the novel derivatives were largely associated with modulating the expression of apoptotic proteins including cIAP-1, cIAP-2, cytochrome c, caspase-3 and caspase-9. Based on the experimental result, we disclosed that the novel NITR spin-labeled RES derivatives exhibit the potential to be used as the novel radioprotective candidates to ameliorate the injury induced by ionizing radiation.

A new strategy for the preparation of mixed-mode chromatographic stationary phases based on modified dialdehyde cellulose.

A new strategy for the preparation of mixed-mode chromatographic stationary phases based on modified dialdehyde cellulose was proposed. Two novel mixed-mode chromatographic stationary phases, dicarboxyl cellulose-modified silica (DCC/SiO2) and (S)-α-phenylethylamine-bonded DCC/SiO2 ((S)-α-PEA/DCC/SiO2), were prepared by utilizing the easy functionalization characteristics of dialdehyde cellulose. The chromatographic evaluation showed that DCC/SiO2 column could be used in hydrophilic interaction liquid chromatography (HILIC) and ion exchange chromatography (IEC) modes, (S)-α-PEA/DCC/SiO2 column could be used in HILIC, IEC and chiral separation modes. The DCC/SiO2 column and (S)-α-PEA/DCC/SiO2 column exhibited excellent chromatographic performance by separating strongly polar compounds, phenylamines and chiral compounds in the above separation modes. The preparation method of modified dialdehyde cellulose-based mixed-mode chromatographic stationary phases was simple, and also provided a new idea for the development of the subsequent novel mixed-mode chromatographic stationary phases.

[Preparation of reversed-phase/hydrophilic chromatographic stationary phase based on dialdehyde microcrystalline cellulose-functionalized C18].

A novel reversed/hydrophilic chromatographic stationary phase based on dialdehyde microcrystalline cellulose (DMCC)-functionalized C18 was prepared by covalent bonding between the amino groups of octadecylamine with the aldehyde groups of DMCC, which was used in reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) modes. The prepared DMCC-functionalized C18 modified silica (C18-DMCC/SiO2) stationary phase exhibited good hydrophobic selectivity and aromatic selectivity by separating alkylbenzenes and polycyclic aromatic hydrocarbons (PAHs) in the RPLC mode. Polar compounds, including anilines, phenols, and glycosides were chosen as analytes to evaluate the polar selectivity of this column in the RPLC mode, and the evaluation results were satisfactory compared with the commercial C18 column. Nucleobases were used for evaluating the hydrophilic interaction liquid chromatography performance of the C18-DMCC/SiO2 column. By investigating the impact of organic solvent content on the retention, it could be found that this new stationary phase had the typical characteristics of reversed-phase/hydrophilic chromatography.

Nanocellulose crystals derivative-silica hybrid sol open tubular capillary column for enantioseparation.

Broad spectrum separation of chiral compounds is a challenge task for analysts. It is significant for preparation of chiral stationary phase and selection of separation technology in the field. Here, we present a novel nanocellulose crystals (NCCs) which were derivation with 3,5-dimethylphenyl isocynate (DMPC) and silane with 3-triethoxysilylpropylisocyanate form sol in tetraethylorthosilicate (TEOS) and layer-by-layer self-assembly in the inner of capillary to fabricate the organic-inorganic hybrid open tubular capillary column (DMPC/NCCs-OTC) for enantiomers separation by capillary electrochromatography technology (CEC). The experimental results verified that this coating column has the broad spectrum separation ability and high resolution efficiency for thirteen different enantiomers at the optimal CEC conditions. The mechanizations of DMPC/NCCs-OTC modified layer numbers and structure effect on chiral separation performance have been investigated and compared. Although the limitation and difficulty in fabrication of open tubular coating column, this work provided the preparation method of stability, controlled, long column life, adequate repeatability and satisfied enantioseparation performance.

An approach toward constructing the trioxadispiroketal core in the DEF-ring of (+)-spirastrellolide A.

A concise and stereoselective synthesis of the trioxadispiroketal motif that embodies the DEF-ring of the marine macrolide (+)-spirastrellolide A is described. The synthetic approach features a sequence of cyclic acetal tethered ring-closing metathesis and Suárez oxidative cyclization, thereby constituting a viable strategy for constructing the Northern Half.