Michael-Michael Addition Reactions Promoted by Secondary Amine-Thiourea: Stereocontrolled Construction of Barbiturate-Fused Tetrahydropyrano Scaffolds and Pyranocoumarins.

Bifunctional secondary amine-thiourea organocatalysts were successfully applied in the stereocontrolled synthesis of barbiturate-fused tetrahydropyrano scaffolds. Compared with typically used tertiary amine-thiourea organocatalysts, the developed catalysts exhibited excellent catalytic performance in the domino Michael-Michael reaction between N, N'-dimethylbarbituric acid and Morita-Baylis-Hillman acetates of nitroalkenes to yield pharmaceutically important heterocycles in good yields with excellent enantioselectivities. Moreover, this catalytic protocol can also be applied to synthesize biologically active pyranocoumarin compounds.

Chiral ligands and photothermal synergistic effects of inorganic nanoparticles for bacteria-killing.

As the drawbacks of antibiotics in treating bacterial infections emerged, physical methods such as near-infrared-activated (NIR-activated) bacterial killing, have attracted great interests for their advantages of no resistance, short action time and few side effects. In this manuscript, NIR-activated bacteria-killing performance of chiral copper sulphide nanoparticles (L-/d-CuS NPs) was investigated using linearly polarized light (LPL) and circularly polarized light (CPL) as illumination sources, respectively. Chiral CuS NPs showed enhanced NIR-activated bacteria-killing effect compared with achiral CuS NPs under the same conditions. Moreover, these chiral CuS NPs showed obvious chirality-related antibacterial effect: the bacterial killing was more efficient under CPL activation, and L- and d-CuS NPs had higher antibacterial efficiency under left circularly polarized light (LCPL) and right circularly polarized light (RCPL), respectively. The possible mechanism of bacteria-killing performance for chiral CuS NPs was discussed in detailed. Photothermal bacteria-killing tests of chiral CuS NPs "sealed" in polydimethylsiloxane (PDMS) demonstrated the individual influence of photothermal effect. These observations in this paper could provide ideas for the potential applications of chiral nanostructures with enhanced photothermal effect in efficient bacterial killing.

Dual-site fluorescent probe for multi-response detection of ClO- and H2O2 and bio-imaging.

Hypochlorite (ClO-) and hydrogen peroxide (H2O2) commonly coexist in organism and are involved in the same physiological and pathological processes. So it is of great importance to develop fluorescent probes to detect both simultaneously. Herein, we reported the first dual-site fluorescent probe (Geisha-1) for the quantitative detection of ClO- and H2O2. This probe is constructed by chemically grafting N,N-dimethylthiocarbamate and borate to a fluorescence resonance energy transfer (FRET) platform. As a result, Geisha-1 not only presents three different responses to ClO-, H2O2, and ClO- + H2O2 (the coexistence of ClO- and H2O2) with high sensitivity and selectivity, but also exhibits low toxicity and cell membrane and tissue permeability, and it was further successfully applied to image ClO- and H2O2 in living cells and tissues. Thus, Geisha-1 provides a promising application prospect in biological systems and an alternative strategy for the construction of dual-site fluorescent probes aiming at the multi-response detection of other biologically relevant analytes.

Essential Oil from Carpesium abrotanoides L. Induces Apoptosis via Activating Mitochondrial Pathway in Hepatocellular Carcinoma Cells.

The effects of essential oil from Carpesium abrotanoides L. (CAEO) on the proliferation and apoptosis of human hepatic cancer cells were investigated in this study. MTT assays indicated that CAEO inhibited the proliferation of HCC cells with the IC50 values ranging from 41.28±3.06 to 130.36±20.79 µg/mL. Moreover, many obviously nuclear morphological changes of apoptotic cells in CAEO-treated HepG2 cells were detected by Hoechst 33258 staining and fluorescence microscopy. Flow cytometry was used to detect cell apoptosis and cell cycle, and noticeable findings showed that CAEO arrested cell-cycle at S and G2/M phases. The decreased Bcl-2/Bax protein ratio and the activation of caspase-3, caspase-9 were also detected by Western blotting. All results suggested that CAEO is a potential agent to fight against liver cancer, and the mitochondria-mediated intrinsic apoptotic pathway could be involved in CAEO-mediated apoptosis of human liver carcinoma cells.