Organocatalytic asymmetric desymmetrization: efficient construction of spirocyclic oxindoles bearing a unique all-carbon quaternary stereogenic center via sulfa-Michael addition.

An unprecedented enantioselective desymmetrization of spiro cyclohexadienone oxindoles has been developed successfully via organocatalyzed asymmetric SMA, which provides facile access to spirocyclic oxindoles bearing a unique all-carbon quaternary stereogenic center with excellent levels of stereoselectivity.

Chemical composition and antioxidant activity of the essential oil of endemic Viola tianshanica.

The composition and in vitro antioxidant activities of the essential oil and methanol extract of the aerial parts of Viola tianshanica were evaluated in this research. GC-MS analysis of the essential oil resulted in the identification of 15 constituents, representing 89.67% of the oil. The major compounds detected in the essential oil were dibutyl phthalate (15.19%), hexadecanoate methyl (8.65%), n-hexadecanoic acid (3.07%) and 2,3-pentanedione (2.62%). Essential oil and methanol extract were tested for their antioxidant activities using 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging and ß-carotene linoleic acid assay. In addition, the total phenol of essential oil, polar subfraction and non-polar subfraction were determined.

Aesculetin-induced apoptosis through a ROS-mediated mitochondrial dysfunction pathway in human cervical cancer cells.

Aesculetin (1) is an important coumarin found in various plant materials. It has been shown to have antiproliferative effects on several types of human cancer cells, but its effect on cervical cancer cells in vitro is unknown. In this study, we investigated that the cytotoxic effect of 1 on a non-cancer cell line (293) was smaller than on a tumor cell line (HeLa). This is the first report showing the possible mechanism of antiproliferative effect of 1 for the prevention of cervical cancer in cell culture models. It was found that 1 inhibited cell viability by inducing apoptosis, as evidenced by the formation of apoptotic bodies, generation of reactive oxygen species (ROS), and the accumulation of cells in the sub-G1 phase. Treatment with compound 1 decreased the cell growth in a dose-dependent manner with an IC(50) value of 37.8 microM. Aesculetin-induced apoptosis was correlated with mitochondrial dysfunction (DeltaPsi(m)), leading to the release of cytochrome c from the mitochondria to the cytosol, as well as the proteolytic activation of caspases in HeLa cells. These results indicate that 1 induces apoptosis in HeLa cells through a ROS-mediated mitochondrial dysfunction pathway.

A novel covalent coupling method for coating of capillaries with liposomes in capillary electrophoresis.

A novel covalent coupling method for coating of capillaries with liposomes has been developed, which includes three steps: (i) epoxy-diol coating, (ii) activation with 2,2,2-trifluoroethanesulfonyl chloride, and (iii) liposome coupling. The coating conditions, such as the reaction time and temperature of liposome coupling, the content of dimyristoylphosphatidylethanolamine in liposomes, were optimized. Vesicles were visualized on the inner silica wall as confirmed by atomic force microscopy. The effectiveness of the coating was demonstrated by investigating the effect of pH of BGE on EOF and separating neutral compounds. The intra- and inter-capillary variations in EOF are 4.02% RSD (n=30) and 6.72% RSD (n=4) respectively, and the coated capillaries can be used to perform analysis at least for one month without any performance deterioration when stored at 4 degrees C. A set of drugs with diverse structures was applied into the developed liposome-coated CE. The normalized capacity factor (K) was introduced to quantitatively evaluate drug-membrane interactions. The relationship between log K and the fraction dose absorbed in humans (Fa%) shows that the liposome-coated CE can be utilized for in vitro prediction of Fa% of drugs that follow the transcellular passive transport route.

Apoptosis of Hela cells induced by extract from Cremanthodium humile.

Cremanthodium humile (C. humile) is a traditional herbal medicine for treatment of inflammation. Based on initial screening results, the purpose of this study was to evaluate the cytotoxic effect on four human cancer cell lines and one non-cancer cell line (293), then to determine the possible mechanisms of cell death elicited by the extract of C. humile on Hela cells. We have found the ether extract of C. humile (CH-EE) strongly decreased the survival rate of the four human tumor cell lines: Hela, A549, HepG2 and SW480. The cytotoxic effect of CH-EE on 293 was smaller than on tumor cell lines. Flow cytometry assays and nuclear staining showed that CH-EE induced apoptosis in Hela cells. This process was accompanied by the collapse of mitochondrial membrane potential, the release of cytochrome c and the activation of caspase-3/7 and -9. Furthermore, CH-EE generated reactive oxygen species (ROS) in Hela cells. These results indicate that CH-EE induces apoptosis in Hela cells through a ROS-mediated mitochondrial dysfunction pathway.

[Synthesis of a novel L-nucleoside, beta-L-D4A and its inhibition on the replication of hepatitis B virus in vitro].

AIM: Nucleoside analogues have become the most promising candidates of anti-HBV drugs. In this study, beta-L-D4A was synthesized and explored its inhibitiory action against hepatitis B virus (HBV) in 2. 2. 15 cells derived from HepG2 cells transfected with HBV genome. METHODS: beta-L-D4A was stereo-controlled synthesized from D-glutamic acid, and the structure was identified by IR, 1H NMR and MS. 2. 2. 15 Cells were placed at a density of 5 x 10(4) per well in 12-well tissue culture plates, and treated with various concentrations of beta-L-D4A for 6 days. At the end, medium was processed to obtain virions by a polyethlene glycol precipitation method. At the same time, intracellular DNA was also extracted and digested with Hind III. Both of the above DNA were subjected to Southern blot, hybridized with a 32P-labeled HBV probe and autoradiographed. The intensity of the autoradiographic bands was quantitated by densitometric scans of computer and EC50 was calculated. 2. 2. 15 cells were also seeded in 24-well tissue culture plates, and cytotoxicity with different concentrations was examined by MTT method. IC50 was calculated. RESULTS: The synthesized compound structure conformed with beta-L-D4A; Autoradiographic bands showed similar for supernatant and intracellular HBV DNA. Episomal HBV DNA was inhibited in a dose-dependent manner. EC50 0.2 micromol x L(-1). The experiment of cytotoxicity gained IC50 200 micromol x L(-10. CONCLUSION: beta-L-D4A has been synthesized successfully. beta-L-D4A possessed potent inhibitory effect on replication of HBV in vitro with low cytotoxicity, TI value was 1 000. It is expected to be developed clinically into a new anti-HBV drug.