Schizandrin A exerts anti-tumor effects on A375 cells by down-regulating H19.

Malignant melanoma (MM) is one of the malignant tumors with highly metastatic and aggressive biological actions. Schizandrin A (SchA) is a bioactive lignin compound with strong anti-oxidant and anti-aging properties, which is stable at room temperature and is often stored in a cool dry place. Hence, we investigated the effects of SchA on MM cell line A375 and its underlying mechanism. A375 cells were used to construct an in vitro MM cell model. Cell viability, proliferation, apoptosis, and migration were detected by Cell Counting Kit-8, BrdU assay, flow cytometry, and transwell two-chamber assay, respectively. The cell cycle-related protein cyclin D1 and cell apoptotic proteins (Bcl-2, Bax, cleaved-caspase-3, and cleaved-caspase-9) were analyzed by western blot. Alteration of H19 expression was achieved by transfecting with pEX-H19. PI3K/AKT pathway was measured by detecting phosphorylation of PI3K and AKT. SchA significantly decreased cell viability in a dose-dependent manner. Furthermore, SchA inhibited cell proliferation and cyclin D1 expression. SchA increased cell apoptosis along with the up-regulation of pro-apoptotic proteins (cleaved-caspase-3, cleaved-caspase-9, and Bax) and the down-regulation of anti-apoptotic protein (Bcl-2). Besides, SchA decreased migration and down-regulated matrix metalloproteinases (MMP)-2 and MMP-9. SchA down-regulated lncRNA H19. Overexpression of H19 blockaded the inhibitory effects of SchA on A375 cells. SchA decreased the phosphorylation of PI3K and AKT while H19 overexpression promoted the phosphorylation of PI3K and AKT. SchA inhibited A375 cell growth, migration, and the PI3K/AKT pathway through down-regulating H19.

The cubane paradigm in bioactive molecule discovery: further scope, limitations and the cyclooctatetraene complement.

The cubane phenyl ring bioisostere paradigm was further explored in an extensive study covering a wide range of pharmaceutical and agrochemical templates, which included antibiotics (cefaclor, penicillin G) and antihistamine (diphenhydramine), a smooth muscle relaxant (alverine), an anaesthetic (ketamine), an agrochemical instecticide (triflumuron), an antiparasitic (benznidazole) and an anticancer agent (tamibarotene). This investigation highlights the scope and limitations of incorporating cubane into bioactive molecule discovery, both in terms of synthetic compatibility and physical property matching. Cubane maintained bioisosterism in the case of the Chagas disease antiparasitic benznidazole, although it was less active in the case of the anticancer agent (tamibarotenne). Application of the cyclooctatetraene (COT) (bio)motif complement was found to optimize benznidazole relative to the benzene parent, and augmented anticancer activity relative to the cubane analogue in the case of tamibarotene. Like all bioisosteres, scaffolds and biomotifs, however, there are limitations (e.g. synthetic implementation), and these have been specifically highlighted herein using failed examples. A summary of all templates prepared to date by our group that were biologically evaluated strongly supports the concept that cubane is a valuable tool in bioactive molecule discovery and COT is a viable complement.

Schizandrin A exerts anti-tumor effects on A375 cells by down-regulating H19

Malignant melanoma (MM) is one of the malignant tumors with highly metastatic and aggressive biological actions. Schizandrin A (SchA) is a bioactive lignin compound with strong anti-oxidant and anti-aging properties, which is stable at room temperature and is often stored in a cool dry place. Hence, we investigated the effects of SchA on MM cell line A375 and its underlying mechanism. A375 cells were used to construct an in vitro MM cell model. Cell viability, proliferation, apoptosis, and migration were detected by Cell Counting Kit-8, BrdU assay, flow cytometry, and transwell two-chamber assay, respectively. The cell cycle-related protein cyclin D1 and cell apoptotic proteins (Bcl-2, Bax, cleaved-caspase-3, and cleaved-caspase-9) were analyzed by western blot. Alteration of H19 expression was achieved by transfecting with pEX-H19. PI3K/AKT pathway was measured by detecting phosphorylation of PI3K and AKT. SchA significantly decreased cell viability in a dose-dependent manner. Furthermore, SchA inhibited cell proliferation and cyclin D1 expression. SchA increased cell apoptosis along with the up-regulation of pro-apoptotic proteins (cleaved-caspase-3, cleaved-caspase-9, and Bax) and the down-regulation of anti-apoptotic protein (Bcl-2). Besides, SchA decreased migration and down-regulated matrix metalloproteinases (MMP)-2 and MMP-9. SchA down-regulated lncRNA H19. Overexpression of H19 blockaded the inhibitory effects of SchA on A375 cells. SchA decreased the phosphorylation of PI3K and AKT while H19 overexpression promoted the phosphorylation of PI3K and AKT. SchA inhibited A375 cell growth, migration, and the PI3K/AKT pathway through down-regulating H19.

Annonalide and derivatives: Semisynthesis, cytotoxic activities and studies on interaction of annonalide with DNA.

The cytotoxic activity of the pimarane diterpene annonalide (1) and nine of its semisynthetic derivatives (2-10) was investigated against the human tumor cell lines HL-60 (leukemia), PC-3 (prostate adenocarcinoma), HepG2 (hepatocellular carcinoma), SF-295 (glioblastoma) and HCT-116 (colon cancer), and normal mouse fibroblast (L929) cells. The preparation of 2-10 involved derivatization of the side chain of 1 at C-13. Except for 2, all derivatives are being reported for the first time. Most of the tested compounds presented IC50s below 4.0 µM, being considered potential antitumor agents. The structures of all new compounds were elucidated by spectroscopic analyses including 2D NMR and HRMS. Additionally, the interaction of annonalide (1) with ctDNA was evaluated using spectroscopic techniques, and the formation of a supramolecular complex with the macromolecule was confirmed. Competition assays with fluorescent probes (Hoechst and ethidium bromide) and theoretical studies confirmed that 1 interacts preferentially via DNA intercalation with stoichiometric ratio of 1:1 (1:ctDNA). The ΔG value was calculated as -28.24 kJ mol-1, and indicated that the interaction process occurs spontaneously. Docking studies revealed that van der Walls is the most important interaction in 1-DNA and EB-DNA complexes, and that both ligands (1 and EB) interact with the same DNA residues (DA6, DA17 and DT19).

The thermochemistry of cubane 50 years after its synthesis: a high-level theoretical study of cubane and its derivatives.

The gas-phase enthalpy of formation of cubane (603.4 ± 4 kJ mol(-1)) was calculated using an explicitly correlated composite method (W1-F12). The result obtained for cubane, together with the experimental value for the enthalpy of sublimation, 54.8 ± 2.0 kJ mol(-1), led to 548.6 ± 4.5 kJ mol(-1) for the solid-phase enthalpy of formation. This value is only 6.8 kJ mol(-1) higher than the 50-year-old original calorimetric result. The carbon-hydrogen bond dissociation enthalpy (C-H BDE) of cubane (438.4 ± 4 kJ mol(-1)), together with properties relevant for its experimental determination using gas-phase ion thermochemistry, namely the cubane gas-phase acidity (1704.6 ± 4 kJ mol(-1)), cubyl radical electron affinity (45.8 ± 4 kJ mol(-1)), cubane ionization energy (1435.1 ± 4 kJ mol(-1)), cubyl radical cation proton affinity (918.8 ± 4 kJ mol(-1)), cubane cation appearance energy (1099.6 ± 4 kJ mol(-1)), and cubyl ionization energy (661.2 ± 4 kJ mol(-1)), were also determined. These values were compared with those calculated for unstrained hydrocarbons (viz., methane, ethane, and isobutane). The strain energy of cubane (667.2 kJ mol(-1)) and cubyl radical (689.4 kJ mol(-1)) were independently estimated via quasihomodesmotic reactions. These values were related via a simple model to the C-H BDE in cubane. Taking into account the accuracy of the computational method, the comparison with high-precision experimental results, and the data consistency afforded by the relevant thermodynamic cycles, we claim an uncertainty better than ±4 kJ mol(-1) for the new enthalpy of formation values presented.

The conformational analysis of 2-halocyclooctanones.

The establishment of the most stable structures of eight membered rings is a challenging task to the field of conformational analysis. In this work, a series of 2-halocyclooctanones were synthesized (including fluorine, chlorine, bromine and iodine derivatives) and submitted to conformational studies using a combination of theoretical calculation and infrared spectroscopy. For each compound, four conformations were identified as the most important ones. These conformations are derived from the chair-boat conformation of cyclooctanone. The pseudo-equatorial (with respect to the halogen) conformer is preferred in vacuum and in low polarity solvents for chlorine, bromine and iodine derivatives. For 2-fluorocyclooctanone, the preferred conformation in vacuum is pseudo-axial. In acetonitrile, the pseudo-axial conformer becomes the most stable for the chlorine derivative. According to NBO calculations, the conformational preference is not dictated by electron delocalization, but by classical electrostatic repulsions.

Purity and adulterant analysis of crack seizures in Brazil.

Cocaine represents a serious problem to society. Smoked cocaine is very addictive and it is frequently associated with violence and health issues. Knowledge of the purity and adulterants present in seized cocaine, as well as variations in drug characteristics are useful to identify drug source and estimate health impact. No data are available regarding smoked cocaine composition in most countries, and the smoked form is increasing in the Brazilian market. The purpose of the present study is to contribute to the current knowledge on the status of crack cocaine seized samples on the illicit market by the police of São Paulo. Thus, 404 samples obtained from street seizures conducted by the police were examined. The specimens were macroscopically characterized by color, form, odor, purity, and adulterant type, as well as smoke composition. Samples were screened for cocaine using modified Scott test and thin-layer chromatographic (TLC) technique. Analyses of purity and adulterants were performed with gas chromatography equipped with flame ionization detector (GC-FID). Additionally, smoke composition was analyzed by GC-mass spectrometry (MS), after samples burning. Samples showed different colors and forms, the majority of which is yellow (74.0%) or white (20.0%). Samples free of adulterants represented 76.3% of the total. Mean purity of the analyzed drug was 71.3%. Crack cocaine presented no correlations between macroscopic characteristics and purity. Smoke analysis showed compounds found also in the degradation of diesel and gasoline. Therefore, the drug marketed as crack cocaine in São Paulo has similar characteristics to coca paste. High purity can represent a greater risk of dependency and smoke compounds are possibly worsening drug health impact.

Catalysts for heterogeneous oxidation reaction based on metalloporphyrins immobilized on kaolinite modified with triethanolamine.

Raw kaolinite was modified with triethanolamine (TEA), in an attempt to create a new support for the immobilization of metalloporphyrins. Anionic metalloporphyrins containing Fe(3+) or Mn(3+) as metallic centers were immobilized on the prepared support, and the obtained solids were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRPD), thermal analysis (thermogravimetric and differential thermal analyses--TGA/DTA), and scanning electron microscopy (SEM). The solids were used in heterogeneous oxidation catalysis of cyclooctene and cyclohexane. The yields from the oxidation of cyclooctene depended on the amount of TEA and/or water present in the solids. Good reaction yields were obtained for the oxidation of cyclohexane, with selectivity for the alcohol. In one specific case, a possible co-catalytic activity was verified for TEA during the oxidation of cyclohexane.

Determination of specific receptor sites for platelet activating factor in bovine neutrophils.

OBJECTIVE: To identify and characterize a platelet activating factor (PAF) receptor in bovine neutrophils by use of radioligand binding, reverse transcription-polymerase chain reaction (RT-PCR) assay, and western blot analysis. ANIMALS: 4 healthy adult cows. PROCEDURE: Bovine neutrophil membranes were isolated for association, dissociation, and saturation binding experiments with PAF labeled with hydrogen 3 (3H-PAF). The RT-PCR assay was performed with appropriate human primers, and western blot analysis was developed with a polyclonal antibody obtained from a peptide of bovine PAF receptor. RESULTS: Analysis of kinetic binding data supported a single class of PAF receptor. Binding of 3H-PAF to membrane preparations was selectively displaced by PAF and a nonhydrolyzable analogue of guanine triphosphate (Gpp[NH]p) and by lyso-PAF (a biologically inactive analogue of PAF) to a lesser extent. Among other PAF receptor antagonists, 14-deoxyandrographolide and WEB 2086 were the most effective in inhibiting 3H-PAF binding sites in neutrophil membranes; 2 lignans, schisandrin-A and gamma-schisandrin were also effective, but 2 gingkolides (BN52020 and BN52021) only mildly inhibited 3H-PAF binding. Results of RT-PCR assay and western blot analysis of neutrophil crude membranes confirmed the presence of a PAF receptor. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that bovine neutrophils express only 1 type of PAF receptor, and it is likely that this receptor is involved in inflammatory responses. The most effective PAF antagonists were 14-deoxyandrographolide and WEB 2086; these PAF antagonists may be potentially useful in the treatment of inflammatory processes in cattle.

Bioactivity of neolignans from fructus Schizandrae.

Fructus Schizandrae sinensis Baill, a traditional Chinese medicine, used as tonic and sedative, has been shown at the beginning of 70's to lower the elevated serum glutamic-pyruvic transaminase (SGPT) levels of patients suffering from chronic viral hepatitis. During past 20 years, a series of neolignans have been isolated and identified as effective principles. Pharmacological studies revealed that they increased liver protein and glycogen synthesis, antagonized liver injuries from CCl4 and thioacetamide. The mechanism of SGPT lowering was considered as a hepato-protective and membrane stabilize action, although inhibition of the activity of liver GPT may also be existed. It was found that some principles of Schizandrae have an inducing effect on hepatic microsomal drug-metabolizing enzyme system P-450, thus explained their anti-toxic, anti-carcinogenic and anti-mutagenic effects. A synthetic derivative compound of Schisandrin called DDB has most of the above mentioned actions now used widely in China as a hepato-protective drug with high effectiveness in normalizing liver functions and very low side effects. From natural Schisandrin to synthesized DDB, pointed out a successful way in the development of new drugs from natural products.