Search results for "Toxicity"
showing 10 items of 2261 documents
New phenolics, cytotoxicity and chemosystematic significance of Atriplex semibaccata
2019
Abstract The chemical characterization of the 70% hydromethanolic extract of Atriplex semibaccata (family: Chenopodiaceae) afforded a new methoxylated flavonol triglycoside, atrisemibaccatoside A (1), and a new lignanamide, (N-[(E)-m-hydroxycinnamoyl]tyramine (7), as well as, five known flavonols (2–6) and two lignanamides (8–9). The structures of the isolated compounds were established depending upon LR&HR-FAB-MS, 1D and 2D NMR spectroscopic analyses. The cytotoxic activity of the isolated compounds (1–4, and 7–9) was investigated. Compounds 7, 8 and 9 weakly inhibited the proliferation of leukemia CCRF-CEM cells with IC50 values of 78.5, 46.3, and 71.2 μg/ml, respectively, and exhibited n…
Deglycosylated bleomycin triggers apoptosis in laryngeal carcinoma cells in a caspase and reactive oxygen species independent manner
2008
Background: Bleomycin-A2, a member of a family of glycopeptide antibiotics, has potent antitumor activity against a range of lymphomas, head and neck cancer and germ cell tumors. However, little is known about the biologic activity of the carbohydrate moiety in Bleomycin-A2-induced cytotoxicity. Methods: We compared the capacity of Bleomycin-A2 and its deglycosylated form (deglycoBleomycin-A2) to induce cell death. Apoptosis was analyzed by cell nuclear staining with Hoechst 33342 dye and DNA fragmentation. The signal transduction pathway was measured through Western blotting and production of reactive oxygen species (ROS). Results: When tested on HEp-2 laryngeal carcinoma cells, Bleomyc…
Isolation, identification and toxicological characterization of TSS 1, a new mycotoxin of the rosenane class.
1990
11-β-hydroxy-7-deoxy-rosenonolactone (TSS1), a product of the pathogenic fungusTrichothecium roseum (Moniliaceae) was isolated from culture medium extracts and completely described in its structure by spectroscopical methods.TSS 1 was classified as a representative of the lactone series of the rosenane class and as a structural isomer to Rosenololactone (1) and Rosololactone (2, 3).TSS1 showed toxic effects in the growth inhibition test toE coli (EC 50: lOμg/mL) andB subtil is (EC 50: 17μg/mL), inhibited fermentation of yeast (EC 50: 2.8μg/mL) and suppressed motility ofAnemia satina larvae (EC 50: 45/μg/mL).Rosenonolactone, the best known representative of that mycotoxin class, showed only …
ChemInform Abstract: Synthesis and Pharmacological Evaluation of 1-Methyl-5- [substituted-4(3H)-oxo-1,2,3-benzotriazin-3-yl]-1H-pyrazole-4-acetic Aci…
2010
Abstract Several new 1-methyl-5-[substituted-4-oxo-1,2,3-benzotriazin-3-yl]-1H-pyrazole-4-acetic acids and their ethyl ester derivatives were prepared. The compounds were tested for analgesic and antiinflammatory activities, acute toxicity, ulcerogenic effect, and as in vitro inhibitors of 3α-hydroxysteroid dehydrogenase (3α-HSD), since it is claimed that the inhibition of such an enzyme predicts in vivo antiinflammatory activity. Some compounds were more active than phenylbutazone in the phenylbenzoquinone and acetic acid peritonitis tests, and equiactive to the same drug in the carrageenin paw edema test. All the compounds inhibited the 3α-HSD, but no correlation was observed with the paw…
Recurrence of the oxazole motif in tubulin colchicine site inhibitors with anti-tumor activity
2021
Abstract Because of its wide spectrum of targets and biological activities, the oxazole ring is a valuable heterocyclic scaffold in the design of new therapeutic agents with anticancer, antiviral, antibacterial, anti-inflammatory, neuroprotective, antidiabetic and antidepressant properties. The presence of two heteroatoms, oxygen and nitrogen, offers possible interactions (hydrogen, hydrophobic, van der Waals or dipoles bonds) with a broad range of receptors and enzymes. Furthermore, the oxazole core conjugates low cytotoxicity with improved compound solubility and is well suited to structural modifications such as substitution with different groups and condensation to aromatic, heteroaroma…
Detoxication Strategy of Epoxide Hydrolase—The Basis for a Novel Threshold for Definable Genotoxic Carcinogens
2004
From our recent work on the three-dimensional structure of epoxide hydrolases we theoretically deduced the likelihood of a two-step catalytic mechanism that we and others have subsequently experimentally confirmed. Analysis of the rate of the two steps by us and by others show that the first step—responsible for removal of the reactive epoxide from the system—works extraordinarily fast (typically three orders of magnitude faster than the second step), sucking up the epoxide like a sponge. Regeneration of the free enzyme (the second step of the catalytic mechanism) is slow. This becomes a toxicological problem only at doses of the epoxide that titrate the enzyme out. Our genotoxicity work s…
Physiological, morphological and metabolic changes in Tetrahymena pyriformis for the in vivo cytotoxicity assessment of metallic pollution: Impact on…
2007
Abstract The individual cytotoxicity of cadmium chloride, iron sulphate and chromium nitrate has been investigated by using the freshwater ciliate Tetrahymena pyriformis. The metabolic enzymes and antioxidant defense biomarkers were assessed. The results obtained reveal that their metal salts have perturbed the physiology and morphology of T. pyriformis. Also, the biomarkers assessed were sensitive to the presence of metal salts and this sensitivity was metal salt and dose dependant. To estimate the impact of their metal salts on mitochondria, we studied their effects in vivo and in vitro on the d -β-hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30) inner mitochondrial membrane enzyme. The …
Effect of?-cyclodextrin complexation on the photohaemolitic activity induced by Ketoprofen and Naproxen sensitization
1993
Red blood cell lysis photosensitized by two non-steroidal anti-inflammatory drugs Naproxen (NAP) and Ketoprofen (KPF) was investigated in the presence of β-cyclodextrin (β-Cyd). The photohaemolysis was inhibited by the addition of β-Cyd both for NAP and, to a lesser extent, for KPF. The protective action was found only in a restricted range of concentration of β-Cyd. Higher amounts of β-Cyd interfered with the resistance of the cell to the osmotic shock induced by the photosensitization process. The complexing action of β-Cyd was ascertained through UV-vis absorption spectroscopy, induced circular dichroism and emission spectroscopy. The isolated complexes Naproxen-β-Cyd (NAP-β-Cyd) and Ket…
Cytotoxicity of an unprecedented brominated oleanolide and a new furoceramide from the Cameroonian spice, Echinops giganteus
2016
A preliminary study on Echinops giganteus (Asteraceae) showed that the methanolic extract has interesting cytotoxicities against a panel of cancer cell lines. From this extract, a lignan, a flavonoid and a polyacetylenic thiophene identified were three times less cytotoxic than the extract. In the search of the metabolites responsible for the bioactivity, a new harvested E. giganteus was subjected to a phytochemical study using chromatographic methods. In the course of the work, two new compounds: a brominated oleanolide (1) and a tetrahydrofurano-ceramide (2) were obtained along with β-amyrin acetate (3), 2-(penta-1,3-diynyl)-5-(4-hydroxybut-1-ynyl)-thiophene (4), 2-(penta-1,3-diynyl)-5-(3…
Sources, Chemistry, and Biological Potential of Ellagitannins and Ellagic Acid Derivatives
2019
Abstract The consumption of polyphenols is considered an important part of a healthy life style and is related to reducing the risk for diseases. Ellagitanins (e.g., vescalagin, punicalagin, and castalagin) and ellagic acid and its derived compounds (e.g., urolithin) have been receiving attention in recent years as bioactive substances. This class of phenolic substances can be found in berries, pomegranates, walnuts, almonds, and other plant material that is consumed as traditional medicine to treat inflammatory diseases. Human gut microbiota are considered to play an important role in the bioactivity of ellagic acid derivative activity due to the production of urolithin and its antiinflamm…