Search results for " TOXICOLOGY AND PHARMACEUTICS"
showing 10 items of 461 documents
Avarol inhibits TNF-a generation and NF-kB activation in human cells and in animal models
2007
Avarol is a marine sesquiterpenoid hydroquinone with interesting pharmacological properties including anti-inflammatory and antipsoriatic effects. In the present study we evaluated the pharmacological effect of avarol on some inflammatory parameters related to the pathogenesis of psoriasis. Avarol inhibited tumor necrosis factor-alpha (TNF-alpha) generation in stimulated human monocytes (IC(50) 1 microM) and TNF-alpha-induced activation of nuclear factor-kappaB (NF-kappaB)-DNA binding in keratinocytes. In the mouse air pouch model, administration of avarol produced a dose-dependent reduction of TNF-alpha generation (ED(50) 9.2 nmol/pouch) as well as of interleukin (IL)-1beta, prostaglandin …
Peptidyl Vinyl Ketone Irreversible Inhibitors of Rhodesain: Modifications of the P2 Fragment.
2020
In this paper, we report the design, synthesis and biological investigation of a series of peptidyl vinyl ketones obtained by modifying the P2 fragment of previously reported highly potent inhibitors of rhodesain, the main cysteine protease of Trypanosoma brucei rhodesiense. Investigation of the structure-activity relationship led us to identify new rhodesain inhibitors endowed with an improved selectivity profile (a selectivity index of up to 22 000 towards the target enzyme), and/or an improved antitrypanosomal activity in the sub-micromolar range.
Effects of some isoxazolpyrimidine derivatives on nitric oxide and eicosanoid biosynthesis
2000
Abstract The inhibitory effect of some isoxazolpyrimidine derivatives on iNOS and COX-2 endotoxin induction in mouse peritoneal macrophages has been studied. Three of these compounds inhibited nitrite and PGE2 accumulation in a concentration dependent-manner at μM range. None of these active compounds affected iNOS, COX-2, COX-1 or PLA2 activities, although some reduced iNOS or COX-2 expression. Besides, no effect was observed on human neutrophil inflammatory responses (LTB4 biosynthesis and Superoxide or elastase release). Active compounds were assayed by oral administration in the mouse air pouch model, where they inhibited nitrite accumulation without affecting PGE 2 levels or leukocyte …
Effects of caffeoyl conjugates of isoprenyl-hydroquinone glucoside and quinic acid on leukocyte function.
2002
The activity of three prenylhydroquinone glucosides (1-3) and four caffeoylquinic esters (4-7), obtained from Phagnalon rupestre, on elastase release, myeloperoxidase activity and superoxide and leukotriene B(4) production from polymorphonuclear leukocytes was determined. 4,5-Dicaffeoylquinic acid strongly inhibited elastase release with an IC(50) value of 4.8 microM. Methylated caffeoylquinic derivatives were the most potent inhibitors of myeloperoxidase (IC(50) near 60 microM), whereas both methylated and free carboxyl isomers inhibited superoxide production with similar potency (IC(50) between 27 and 42 microM). The monocaffeoyl conjugate of prenylhydroquinone glucoside (3), the most pot…
Genetic signature consistent with selection against the CYP3A4*1B allele in non-African populations.
2005
Cytochrome P450 3A enzymes (CYP3A) play a major role in the metabolism of steroid hormones, drugs and other chemicals, including many carcinogens. The individually variable CYP3A expression, which remains mostly unexplained, has been suggested to affect clinical phenotypes. We investigated the CYP3A locus in five ethnic groups. The degree of linkage disequilibrium (LD) differed among ethnic groups, but the most common alleles of the conserved LD regions were remarkably similar. Non-African haplotypes are few; for example, only four haplotypes account for 80% of common European Caucasian alleles. Large LD blocks of high frequencies were suggestive of selection. Accordingly, European Caucasia…
Transcriptional up-regulation of nNOS in the dorsal vagal complex during low endotoxemia
2005
The present study analyses the expression and distribution of neuronal nitric oxide synthase (nNOS) in the brainstem of animals pre-treated with Escherichia coli or Helicobacter pylori LPS, at doses that modulate gastric motor function. Systemic administration of H. pylori LPS prevented in a dose-dependent manner (5, 40 and 100 microg kg(-1), i.v.) the increase in intragastric pressure induced by 2-deoxy-D-glucose (200 mg kg(-1), i.v.) in urethane-anaesthetized rats. Quantitative analysis showed a significant increase in the amount of nNOS mRNA induced by E. coli or H. pylori LPS (2 h later), in a segment of the brainstem containing the dorsal vagal complex (DVC). Immunohistochemical studie…
Expression and function of the non-neuronal cholinergic system in endothelial cells
2003
Increasing evidence has shown the expression of the non-neuronal cholinergic system in endothelial cells. In the present experiments the expression of choline acetyltransferase (ChAT) was investigated in human endothelial cells by anti-ChAT immunohistochemistry and anti-ChAT immunofluorescence. Positive ChAT immunoreactivity was found in cultures of human umbilical endothelial cells (HUVEC) and a human angiosarcoma cell line (HAEND). In HUVEC and HAEND choline acetyltransferase activity and small amounts of acetylcholine were also detected. Positive ChAT-immunoreactivity was demonstrated in situ in endothelial cells of the human umbilical cord. In addition, in experiments with confocal lase…
a1D-Adrenoceptors are responsible for the high sensitivity and the slow time-course of noradrenaline-mediated contraction in conductance arteries.
2013
The objective of this study was to determine whether the different time-course characteristics of α1-adrenoceptor-mediated contraction in arteries can be related to the subtypes involved. Contractile responses to noradrenaline (NA) were compared with inositol phosphate accumulation and extracellular signal-regulated kinase (ERK)1/2 phosphorylation after α1-agonist stimuli in the same vessels in the presence or absence of α1-antagonists in rat or in α1-subtype knockout (KO) mice. Aorta, where α1D-AR is the main functional subtype, had higher sensitivity to NA (in respect of inositol phosphate [IP], pERK1/2, and contractile response) than tail artery, where the α1A-adrenoceptor subtype is pre…
New Tetromycin Derivatives with Anti-Trypanosomal and Protease Inhibitory Activities
2011
Four new tetromycin derivatives, tetromycins 1-4 and a previously known one, tetromycin B (5) were isolated from Streptomyces axinellae Pol001(T) cultivated from the Mediterranean sponge Axinella polypoides. Structures were assigned using extensive 1D and 2D NMR spectroscopy as well as HRESIMS analysis. The compounds were tested for antiparasitic activities against Leishmania major and Trypanosoma brucei, and for protease inhibition against several cysteine proteases such as falcipain, rhodesain, cathepsin L, cathepsin B, and viral proteases SARS-CoV M(pro), and PL(pro). The compounds showed antiparasitic activities against T. brucei and time-dependent inhibition of cathepsin L-like proteas…
Vasoactive properties of antihypertensive lactoferrin-derived peptides in resistance vessels: Effects in small mesenteric arteries from SHR rats
2017
Aims: Bovine lactoferrin (LF) hydrolysates and peptides identified thereof have shown antihypertensive effects in rat models, mainly but not exclusively by angiotensin-converting enzyme inhibition. In this study we aimed to assess the vasoactive effects and mechanisms of an ultrafiltered (< 3 kDa) pepsin LF hydrolysate (LFH) and a heptapeptide identified in a LF hydrolysate produced by yeast proteolysis (DPYKLRP) in peripheral resistance arteries from spontaneously hypertensive rats (SHRs). Main methods: We used a myograph system for isometric tension recording in isolated small mesenteric arteries from SHRs. Direct vasoactive effects of LFH (30–100 μg/mL) and DPYKLRP (30–100 μM) were asses…