Comparison of two methods for tumour-targeting peptide modification of liposomes.

Liposomes decorated with tumour-targeting cell-penetrating peptides can enhance specific drug delivery at the tumour site. The TR peptide, c(RGDfK)-AGYLLGHINLHHLAHL(Aib)HHIL, is pH-sensitive and actively targets tumour cells that overexpress integrin receptor αvß3, such as B16F10 melanoma cells. Liposomes can be modified with the TR peptide by two different methods: utilization of the cysteine residue on TR to link DSPE-PEG2000-Mal contained in the liposome formula (LIPTR) or decoration of TR with a C18 stearyl chain (C18-TR) for direct insertion into the liposomal phospholipid bilayer through electrostatic and hydrophobic interactions (LIPC18-TR). We found that both TR and C18-TR effectively reversed the surface charge of the liposomes when the systems encountered the low pH of the tumour microenvironment, but LIPC18-TR exhibited a greater increase in the charge, which led to higher cellular uptake efficiency. Correspondingly, the IC50 values of PTX-LIPTR and PTX-LIPC18-TR in B16F10 cells in vitro were 2.1-fold and 2.5-fold lower than that of the unmodified PTX-loaded liposomes (PTX-LIP), respectively, in an acidic microenvironment (pH 6.3). In B16F10 tumour-bearing mice, intravenous administration of PTX-LIPTR and PTX-LIPC18-TR (8 mg/kg PTX every other day for a total of 4 injections) caused tumour reduction ratios of 39.4% and 56.1%, respectively, compared to 20.8% after PTX-LIP administration. Thus, we demonstrated that TR peptide modification could improve the antitumour efficiency of liposomal delivery systems, with C18-TR presenting significantly better results. After investigating different modification methods, our data show that selecting an adequate method is vital even when the same molecule is used for decoration.

Enantioselective N-heterocyclic carbene-catalyzed synthesis of indenopyrones.

The chiral N-heterocyclic carbene-catalyzed [4 + 2] cyclization of α-chloroaldehydes and arylidene indanediones was developed, giving the corresponding indenopyrones in good yields with high diastereoselectivities and enantioselectivities.

N-heterocyclic carbene-catalyzed highly enantioselective synthesis of substituted dihydropyranopyrazolones.

Highly optically pure multisubstituted dihydropyrano[2,3-c]pyrazol-6-(1H)-ones were synthesized via the N-heterocyclic carbene-catalyzed enantioselective [4 + 2] annulation of α-chloroaldehydes and pyrazolone-derived oxodienes.

Three-Dimensional Carbon Foam Modified with Mg3N2 for Ultralong Cyclability of a Dendrite-Free Li Metal Anode.

Uncontrolled growth of lithium dendrites and huge volume change during the lithium plating/stripping process as well as poor mechanical properties of the solid electrolyte interphase (SEI) are key obstacles to the development of a stable Li metal anode. Here, an ultralight Mg3N2-modified carbon foam (CF-Mg3N2) was fabricated as a collector to address these issues. The calculated results show that the CF-Mg3N2 composite is relatively stable in terms of energy. Based on the synergistic effect of the three-dimensional skeleton and the lithiophilic nature of Mg3N2, homogeneous lithium deposition/stripping was realized around the foam carbon skeleton with an extremely low nucleation overpotential (∼9.3 mV) and high retention of Coulombic efficiency (99.3%) as well as long cyclability (700 cycles and 3000 h in half and symmetrical cells, respectively). Meanwhile, Mg3N2-CF@Li//LiFePO4 full cells also showed better rate capability and more stable cycling capability than CF@Li//LiFePO4 and Li//LiFePO4 cells, exhibiting extreme practicality. Accordingly, the design concept mentioned in this work provides a far-reaching influence on the development of a stable Li metal anode.

Controlled Synthesis of Co@N-Doped Carbon by Pyrolysis of ZIF with 2-Aminobenzimidazole Ligand for Enhancing Oxygen Reduction Reaction and the Application in Zn-Air Battery.

The Co/N-doped carbon material, as an important electrocatalytic material, has been attracted intense interest in ORR and Zn-air battery. Here, we report an efficient Co@N-doped carbon catalyst (Co@N-C-1) obtained by pyrolysis of ZIF precursor with 2-aminobenzimidazole. The introduction of 2-aminobenzimidazole results in the formation of hierarchical meso/microporous structure of the as-prepared Co@N-C-1, effectively avoiding the aggregation of Co nanoparticles during pyrolysis and the higher N content, which contributes to enhance the ORR electrocatalytic activities. The obtained Co@N-C-1 exhibits remarkable ORR performance with a half-wave potential of 0.938 V vs RHE in alkaline media. As the air catalyst of zinc-air batteries, Co@N-C-1 displays 1.439 V of open-circuit voltage and 1413.3 Wh·kg-1 of energy density.

Antifungal activity of crude extracts and fat-soluble constituents of Holotrichia diomphalia larvae.

In this study, chemical compositions of fatty oils and bioactivity of crude extracts from Holotrichia diomphalia larvae as Chinese materia medica were investigated for the first time. The chemical compositions of the fatty oils were obtained by two different methods and determined by GC/MS. In total, the petroleum ether extract produced 21 compounds (96.3%) while the supercritical fluid extract produced six compounds (99.53%) for identification. The effect of petroleum ether and other crude extracts on Pyricularia oryzae was also examined. Results indicated that ethanol and petroleum ether extracts had excellent antifungal activities. These findings demonstrated that fatty oils from H. diomphalia larvae had great potential to be used as a source for natural health products.

[Determination of safflor yellow A by RP-HPLC and resources quality comparison in Carthamus tinctorius].

OBJECTIVE: To provide the basis for establishing evaluation criterion, selecting good strains and carring out good agricultural practice of the crude drug. METHOD: Representative 22 varieties of Carthamus tinctorius were selected and cultivated in different ecological localities and different years. And the content of safflor yellow A in their corollas were measured by RP-HPLC to compare the differences and their genetic stabilities among varieties. RESULT: The range of of safflor yellow A content was 0.70%-1.85% which were varied among varieties (P < 0.01). The content of safflor yellow A in varieties Yutai Honghua, Hefei Honghua, Rucheng Honghua were higher than in others. CONCLUSION: The effective compound safflor yellow A in C. tinctorius was one of the main quality evaluation criterions. Varieties Yutai Honghua, Hefei Honghua and Rucheng Honghua were good resources.

Brønsted Acid-Catalyzed Synthesis of N-Arylindoles from 2-Vinylanilines and Quinones.

In the presence of a quinone, Brønsted acid-catalyzed intramolecular C-N bond formation of o-vinylanilines by electrophilic cyclization was developed, giving the corresponding N-arylindoles in good to high yields. The reaction worked well for o-vinylanilines with terminal and internal C=C double bonds.

N-Heterocyclic carbene-catalyzed [3+3] cyclocondensation of bromoenals with aldimines: highly enantioselective synthesis of dihydropyridinones.

The N-heterocyclic carbene-catalyzed [3+3] cyclocondensation of bromoenals and aldimines was developed to give the corresponding dihydropyridinones in good yields with excellent enantioselectivities.

Enantioselective Synthesis of Bicyclic δ-Lactones via N-Heterocyclic Carbene-Catalyzed Cascade Reaction.

The N-heterocyclic carbene-catalyzed cascade reaction of enals with malonates to give bicyclic δ-lactones was developed. The cyclopentane- and cyclohexane-fused δ-lactones with three continued stereocenters were obtained in high yields with excellent diastereo- and high enantioselectivities.

[A new alkaloids isolated from tetraploidy banlangen].

AIM: To investigate the chemical constituents of tetraploidy Banlangen (Isatis indigotica Fort.). METHODS: Compounds were separated by chromatography on silica gel. Their structures were determined by spectral analysis and chemical evidence. RESULTS: Three compounds were isolated. Their structures were identified as (E)-2-[(3'-indole) cyanomethylene]-3-indolinone (I), 2-(4-hydroxy-3-methoxyphenyl)-4-[(4-hydroxy-3-methoxy-phenyl)-methyl]-3- hydroxymethyl-tetrahydro-furan (II) and 2-methoxy-4-[tetrahydro-4-[(4-hydroxy-3-methoxy-phenyl)-methyl]-3- hydroxymethyl-2-furanyl] phenyl-1-O-beta-D-glucopyranoside (III). CONCLUSION: Compound I is a new compound.

Bifunctional N-heterocyclic carbene-catalyzed highly enantioselective synthesis of spirocyclic oxindolo-ß-lactams.

The N-heterocyclic carbene-catalyzed Staudinger reaction of ketenes with isatin-derived ketimines was investigated. The bifunctional NHCs with a free hydroxyl group were demonstrated as efficient catalysts for the reaction, giving the corresponding spirocyclic oxindolo-ß-lactams in high yields with excellent diastereo- and enantioselectivities.

[Experimental studies of Panax notoginseng saponins and Ginkgo biloba extracts on preventing acute oxygen toxicity].

AIM: To investigate the preventive effects of Panax notoginseng saponins (PNS) and Ginkgo biloba extracts (GbE) on acute oxygen toxicity and the possible mechanisms. METHODS: Mice were injected intraperitoneally with PNS and GbE for 5 days, then were exposed to 500 kPa hyperbaric oxygen (HBO) for 60 min, the convulsion latency, times and interval were observed. Moreover, reactive oxygen (RO) unit, MDA, NO, GSH levels and GSH-Px, CAT, MAO activities of mice brain were determined after they were exposed to HBO for 15 min. RESULTS: PNS and GbE could markedly prolong the convulsion latency and interval, reduce convulsion times, decrease contents of MDA and NO in mice brain, keep RO unit, GSH and GSH-Px at higher levels, but had no effects on CAT and MAO activities. CONCLUSION: PNS and GbE could effectively prevent acute oxygen toxicity, which were related to their antioxidant activities.