Search results for "relationship"
showing 10 items of 3616 documents
General considerations in the interpretation of I-J genetic restrictions: evidence that the antigen-binding chain of antigen-specific T-suppressor fa…
1987
SUMMARY (CBA × B10)F1 [(H-2k x H-2b)] mice produce two types of antigen-specific T-suppressor factor (TsF), which can be separated by affinity chromatography on anti-I-J monoclonal antibody. After reduction and alkylation, both chains of F1 TsF are required for biological activity. However, the antigen-binding chain (AgBC) of F1 TsFk (AgBCk) is only complemented by I-Jk and likewise for F1 TsFb. In other words, interchain complementation shows the same genetic restriction in interchain complementation in parental and F1 mice. F1 TsF bearing, for example, I-Jk (TsFk), interacts with haptenized ‘antigen-presenting cells’ (‘APC’) of both parental haplotypes, and may be described as showing dua…
Anti-inflammatory activity of two cucurbitacins isolated from Cayaponia tayuya roots.
2004
Fractionation of an anti-inflammatory extract from Cayaponia tayuya roots yielded two active compounds, identified as 23,24-dihydrocucurbitacin B (1) and cucurbitacin R (2). Both were evaluated for their anti-inflammatory activity on several experimental models of pain and inflammation. In addition, their cytotoxicity and effects on leukotriene B 4 (LTB 4 ) formation were evaluated in rat polymorphonuclear leukocytes. Both compounds showed activity in the following models: carrageenan-induced mouse paw oedema (1, 4 mg/kg p.o., 46% inhibition at 3 h), phospholipase A 2 -induced mouse paw oedema (2, 3 mg/kg i.p., 61% inhibition at 60 min), serotonin-induced mouse paw oedema (1 and 2, 0.5 mg/k…
A Mechanistic Approach to theIn VivoAnti-Inflammatory Activity of Sesquiterpenoid Compounds Isolated fromInula viscosa
2001
The present study was designed to examine the anti-inflammatory activity of the sesquiterpenoids ilicic acid and inuviscolide, isolated from Inula viscosa, on cell degranulation, leukotriene biosynthesis, neurogenic drive and glucocorticoid-like interactions. Swiss female mice were used to measure the ear oedema induced by phorbol esters or ethyl phenylpropiolate (EPP), and the paw oedema induced by phospholipase A(2) (PLA(2)) or serotonin. Drug treatment consisted of one topically-applied dose in the ear models and a subcutaneous or intraperitoneal injection in the paw models. Quantitative analysis of leukotriene B(4) (LTB(4)) formation was performed on rat peritoneal neutrophils by high p…
(+)-Dehydroabietylamine derivatives target triple-negative breast cancer.
2015
Breast cancer remains the leading cause of cancer-related death among women. The invasive triple-negative subtype is unresponsive to estrogen therapy, and few effective treatments are available. In search of new chemical scaffolds to target this disease, we conducted a phenotypic screen against the human breast carcinoma cell lines MDA-MB-231, MA11, and MCF-7 using terrestrial natural products. Natural products that preferentially inhibited proliferation of triple-negative MDA-MB-231 cells over estrogen receptor-positive cells were further studied; herein we focused on the abietanes. The activity of the abietane carnosol prompted us to generate a focus library from the readily available (+)…
Kaempferol as a dietary anti-inflammatory agent: current therapeutic standing
2020
Inflammation is a physiological response to different pathological, cellular or vascular damages due to physical, chemical or mechanical trauma. It is characterized by pain, redness, heat and swelling. Current natural drugs are carefully chosen as a novel therapeutic strategy for the management of inflammatory diseases. Different phytochemical constituents are present in natural products. These phytochemicals have high efficacy both in vivo and in vitro. Among them, flavonoids occur in many foods, vegetables and herbal medicines and are considered as the most active constituent, having the ability to attenuate inflammation. Kaempferol is a polyphenol that is richly found in fruits, vegetabl…
Benzodiazepines: specific competitors for the binding of L-tryptophan to human serum albumin.
1975
By means of the gel filtration technique, the effect of nine benzo-diazepine derivates on the binding of l-tryptophan to human serum albumin was investigated. Using equimolar tryptophan and benzodiazepine concentrations, all benzodiazepines with binding constants higher than 104 (M−1), displace l-tryptophan from its binding site to a high degree. The mechanism of the displacement was characterized as a competition for a common binding site. Some of the benzodiazepines displace l-tryptophan to a greater extent than salicylic acid. The benzodiazepines and tryptophan are the only substances known with a high degree of stereospecific binding to human serum albumin. This study shows that there i…
Synthesis, biological evaluation, and structure-activity relationship study of novel cytotoxic aza-caffeic acid derivatives.
2010
Abstract Three series of aza-caffeic acid derivatives with different linkers were designed and synthesized. Each of the synthesized derivatives was then used in cytotoxicity screening on either 8 or 12 human cancer cell lines. The structure–activity relationships on three structural regions A, B, and C are analyzed in detail, indicating that a nine bond linker B, containing a piperazine unit, is the most favorable linker leading to the generation of molecules with potent cytotoxicities. Compound ( E )-1-(4-(3,4-dichlorobenzyl)piperazin-1-yl)-3-(4-(4-ethoxybenzyloxy)-3,5-dimethoxyphenyl)prop-2-en-1-one ( 80 ) exhibited the most significant and selective cytotoxicity to KB, BEL7404, K562, and…
Prediction of quinolone activity against Mycobacterium avium by molecular topology and virtual computational screening.
2000
ABSTRACT We conducted a quantitative structure-activity relationship study using a database of 158 quinolones previously tested against Mycobacterium avium-M. intracellulare complex in order to develop a model capable of predicting the activity of new quinolones against the M. avium-M. intracellulare complex in vitro. Topological indices were used as structural descriptors and were related to anti- M. avium-M. intracellulare complex activity by using the linear discriminant analysis (LDA) statistical technique. The discriminant equation thus obtained correctly classified 137 of the 158 quinolones, including 37 of a test group of 44 randomly chosen compounds. This model was then applied to 2…
Anti- Toxoplasma Activities of 24 Quinolones and Fluoroquinolones In Vitro: Prediction of Activity by Molecular Topology and Virtual Computational Te…
2000
ABSTRACT The apicoplast, a plastid-like organelle of Toxoplasma gondii , is thought to be a unique drug target for quinolones. In this study, we assessed the in vitro activity of quinolones against T. gondii and developed new quantitative structure-activity relationship models able to predict this activity. The anti- Toxoplasma activities of 24 quinolones were examined by means of linear discriminant analysis (LDA) using topological indices as structural descriptors. In parallel, in vitro 50% inhibitory concentrations (IC 50 s) were determined in tissue culture. A multilinear regression (MLR) analysis was then performed to establish a model capable of classifying quinolones by in vitro acti…
Development and biological investigations of hypoxia-sensitive prodrugs of the tyrosine kinase inhibitor crizotinib
2019
Despite the huge success of tyrosine kinase inhibitors as anticancer agents, severe side effects are a major problem. In order to overcome this drawback, the first hypoxia-activatable 2-nitroimidazole-based prodrugs of the clinically approved ALK and c-MET inhibitor crizotinib were developed. The 2-aminopyridine functionality of crizotinib (essential for target kinase binding) was considered as ideal position for prodrug derivatization. Consequently, two different prodrugs were synthesized with the nitroimidazole unit attached to crizotinib either via carbamoylation (A) or alkylation (B) of the 2-aminopyridine moiety. The successful prodrug design could be proven by docking studies and a dr…