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Placental drug transfer in near-term ewes: acetylsalicylic and salicylic acid.

Radiolabelled acetylsalicylic acid (ASA) and salicylic acid (SA) were given intravenously to four near-term ewes and their occurrence in both maternal and fetal plasma was ascertained using a specific thin-layer chromatographic analysis procedure. Findings proved that ASA and SA cross the placental barrier and reach distribution equilibrium about 40 min after salicylate administration. The equilibrium plasma fetal/maternal ratio for both salicylates averaged 0.4. Plasma concentrations of the two compounds in the mother and the fetus accorded with a two-compartment model having unusually large mean estimates (54 and 39 L) for the tissue distribution space of ASA and SA, respectively. Furthermore, the mean SA clearance in the ewe (358 mL X min-1) was much greater than that reported in man, while the mean ASA clearance (764 mL X min-1) was similar. Since ASA is an irreversible inhibitor of arachidonate cyclooxygenase, our findings reassert the need for caution in the use of the drug during pregnancy.

Animals↗

Construction and evaluation of nagR-nagAa::lux fusion strains in biosensing for salicylic acid derivatives.

The NagR protein is a response regulatory protein found in the bacterium Ralstonia sp. U2 that is involved in sensing for salicylic acid and the subsequent induction of the operon just upstream of its gene. The genes encoded for in this operon are involved in the degradation of salicylic acid. Escherichia coli strain RFM443 carrying a fusion of the Photorhabdus luminescens luxCDABE operon with the nagR gene and upstream region of the nagAa gene was constructed and characterized with respect to its optimum temperature, its response time and kinetics, and its ability to detect numerous benzoic acid derivatives. Although capable of detecting 0.5 mM salicylic acid at any temperature between 28 and 40 degrees C, this E. coli strain, labeled DNT5, showed its greatest relative activity at 30 degrees C, i.e., the temperature at which the largest induction was seen. Furthermore, experiments done with numerous benzoic acid derivatives found the NagR protein to be responsive to only a few of the compounds tested, including salicylic acid and 3-methyl salicylic acid, and acetyl salicylic acid was the strongest inducer. The lower limits of detection for these compounds with E. coli strain DNT5 were also established, with the native inducer, salicylic acid, giving the most sensitive response and detectable down to a concentration of about 2 microM. A second lux fusion plasmid was also constructed and transformed into an NahR background, Pseudomonas putida KCTC1768. Within this strain, NAGK-1768, the supplemental activity of the NahR protein on the nagAa promoter, was shown to extend both the range of chemicals detected and the sensitivity.

Benzene↗

Histologic changes in the skin of hairless mice following peeling with salicylic acid.

OBJECTIVE: To clarify the histologic alterations produced by the application of salicylic acid solution, which has been used effectively in chemical peeling without producing a wound or inflammation. DESIGN: We applied 7.5%, 15.0%, and 30.0% salicylic acid in solutions of ethanol or macrogol to the backs of hairless mice for 20 minutes. The skin was histologically evaluated immediately and at 1, 3, 12, 24, and 48 hours following treatment. SETTING: The Department of Dermatology, Faculty of Medicine, Kyushu University, Fukuoka, Japan. MAIN OUTCOME MEASURES: A loss of cornified cells was the only morphologic alteration associated with the treatment, and was followed by the activation of the epidermal basal cells and the underlying fibroblasts. RESULTS: The 7.5% and 15. 0% salicylic acid solutions produced few histologic changes, whereas the 30.0% salicylic acid in both vehicles macerated and then exfoliated the cornified cells. As the epidermis became thinner, the residual epidermal cells became flattened and were rearranged parallel to the tensile surface load. The cornified material within the hair follicles also became macerated, dilated the follicles, and then dropped off. An apparent increase occurred in the number of cells in the S phase in the epidermal basal cells in 24 hours, leaving the follicular cells unchanged. As the cornified layer thickened in 48 hours, the epidermal cells below it and the underlying fibroblasts resumed their random pretherapy arrangement. Except for the occasional infiltrate of lymphocytes, no degenerative or inflammatory changes occurred. While similar changes occurred with each vehicle, they were relatively faster with the ethanol preparations. CONCLUSION: The present results suggest that the architecture of the epidermis and the papillary dermis can be regenerated by simply injuring the cornified layer by using topical agents such as salicylic acid that do not cause degeneration or inflammation.

Animals↗

Simultaneous determination of acetylsalicylic and salicylic acids in human serum and aspirin formulations by second-derivative synchronous fluorescence spectrometry.

A second-derivative synchronous scanning spectrofluorimetric method for the simultaneous determination of acetylsalicylic acid (ASA) and salicylic acid (SA) is described. The method is based on the native fluorescence of both acids in a 1% acetic acid-chloroform solution. Both ASA and SA can be determined within the concentration ranges 0.2-70 and 0.03-10 micrograms ml-1, respectively. The effect of each acid on the signal of the other has been studied in detail. Empirical equations have been used to overcome this effect, thus allowing the accurate determination of both acids in binary mixtures, without a separation step. The method has been applied to the determination of ASA and SA in blood serum and to the determination of SA impurities in aspirin formulations. Recoveries from sera spiked with both ASA (2.5-50 micrograms ml-1) and SA (100-160 micrograms ml-1) varied from 99.5 to 106.7% (mean = 102.6%) and from 93.0 to 98.0% (mean = 95.8%), respectively. Recoveries of SA from spiked aspirin solutions (0.25-1.5 mg g-1 of aspirin) varied from 98.0 to 102.0% (mean = 100.3%).

Aspirin↗

Effect of triflusal and other salicylic acid derivatives on cyclic AMP levels in rat platelets.

The effect of triflusal, acetylsalicylic acid (ASA), and of their principal metabolites 2-hydroxy-4-trifluoromethylbenzoic acid (HTB) and salicylic acid (SA), alone or combined with dypiridamole (DIP) and/or PGE1 on cyclic AMP levels in washed rat platelets (37 degrees C, 4 min), has been determined. DIP at 0.1 mM increased cyclic AMP levels by 25%. The effect of triflusal and HTB was significant at therapeutic concentrations of triflusal (1 mM: 36% increase) and HTB (0.5 mM: 37% increase). The effect of HTB was always greater than that of triflusal. ASA, at 1 mM and 5 mM, alone or combined with PGE1 was without effect. When 1 mM triflusal was combined with 0.1 mM DIP an increased effect was obtained (95%). ASA, at the highest concentration tested (5 mM), did not modify the DIP-induced increase of cyclic AMP levels.

Alprostadil↗

Dose-dependent competitive block by topical acetylsalicylic and salicylic acid of low pH-induced cutaneous pain.

In a human acid pain model, which uses continuous intradermal pressure infusion of a phosphate-buffered solution (pH 5.2) to induce localized non-adapting pain, the flow was adjusted to result in constant pain ratings of about 20% or 50% on a visual analog scale (VAS). Six volunteers in each group participated in 4 different placebo-controlled double-blind cross-over studies to measure rapidly evolving cutaneous analgesia from topically applied new ointment formulations of acetylsalicylic acid (ASA) and salicylic acid (SA) as well as of commercial ibuprofen and benzocain creams. Similar, log-linear dose-response curves were found for both ASA and SA, significant in effect at 3 g/kg and higher drug contents and reaching saturation level at 15 or 30 g/kg, respectively, which, 20 min after application, caused a mean pain suppression of 95% using ASA and 80% using SA. Half-maximal effects were achieved using 3 g/kg ASA or 15 g/kg SA. The SA action was also clearly slower to develop. With an increased flow of the acidic buffer, producing lower effective tissue pH and more intense pain, the effect of ASA and SA decreased to 73% pain suppression. A competitive mechanism of both drug effects was suggested by the fact that, with 15 g/kg ASA and SA, pain reduction could be reversed by increasing the buffer flow by a factor of 1.75, on average. Commercial ibuprofen (50 g/kg) and benzocain creams (100 g/kg) were comparably as effective as ASA and SA, but the local anesthetic caused a loss of all cutaneous sensations while the touch threshold (von Frey) under the specific analgesics was the same as under the placebo ointment. Thus, topical applications of non-steroidal anti-inflammatory drugs (NSAIDS) dissolved in different ointment formulations have proven dose-dependently effective and specific in suppressing experimental acidotic pain by a local and competitive mechanism.

Administration, Topical↗

Differences in the kinetics and scale of signalling molecule production modulate the ozone sensitivity of hybrid poplar clones: the roles of H2O2, ethylene and salicylic acid.

Hydrogen peroxide (H(2)O(2)), ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC) and salicylic acid (SA) concentrations and ACC synthase (ACS) gene expression were measured to establish whether the high sensitivity of the Populus deltoides x maximowiczii clone Eridano to ozone (O(3)) exposure, compared with the O(3)-resistant Populus deltoides x euramericana clone I-214, is attributable to differences in the modulation of signal transduction pathways. In a time-course experiment, Populus deltoides (poplar) clones were exposed to acute fumigation with 150 nl l(-1) O(3) for 5 h. The two poplar clones showed differences in ethylene evolution, I-214 displaying earlier and less pronounced ethylene emission than Eridano. In both clones, ethylene evolution was accompanied by increased ACS transcript levels and enhanced emission of free ACC. I-214 exhibited a greater basal concentration of free SA and a lower concentration of the conjugated pool. However, a slight accumulation of free SA at the end of the 5-h exposure was found only in Eridano, together with an earlier minimal increase in the concentration of conjugated SA. The results show that both clones react to O(3) by producing H(2)O(2), ethylene and SA, but the difference in sensitivity to the pollutant is probably attributable to differences in the kinetics and magnitude of this response.

Base Sequence↗

Active oxygen species in the induction of plant systemic acquired resistance by salicylic acid.

A complementary DNA encoding a salicylic acid (SA)-binding protein has been cloned. Its properties suggest involvement in SA-mediated induction of systemic acquired resistance (SAR) in plants. The sequence of the protein is similar to that of catalases and the protein exhibits catalase activity. Salicylic acid specifically inhibited the catalase activity in vitro and induced an increase in H2O2 concentrations in vivo. H2O2 or compounds, such as SA, that inhibit catalases or enhance the generation of H2O2, induced expression of defense-related genes associated with SAR. Thus, the action of SA in SAR is likely mediated by elevated amounts of H2O2.

Amino Acid Sequence↗

Interaction of salicylic acid with verrucae assessed by FT-Raman spectroscopy.

FT-Raman spectroscopy has been used to investigate treated verrucae (warts from the sole of the foot) with a local application of a salicylic acid paint. Differences in the molecular structure of the stratum corneum across the verruca sample were observed, and by comparison with normal and hyperkeratotic skin it was concluded that the tissue around the edges of the verrucae was typically hyperkeratotic skin. In the centre of the verruca, the molecular structure of the skin was altered showing evidence of the interaction with salicylic acid. Salicylic acid was not observed in its characteristic dimerised acid structure, but spectroscopic evidence suggested that fission of the intermolecular H-bonding essentially cleaved the dimer. Observed changes in the v(CCO) stretching mode of the carboxyl and hydroxyl groups indicate the inter H-bonds have broken. These spectral changes are believed to be more consistent with salicylic acid bonding within the human papillomavirus-containing verruca tissue rather than simple acid dissociation upon dissolution in water within the tissue. No evidence for the presence of the other paint components, lactic acid and flexible collodion, was found in the verrucae spectra. This Raman approach may help to elucidate the molecular basis for therapeutic agents interacting with diseased skin.

Humans↗

Salicylic acid blocks indomethacin-induced cyclooxygenase inhibition and lesion formation in rat gastric mucosa.

Salicylic acid has been shown to decrease gastric mucosal lesions induced by indomethacin in the rat. In vitro, it has also been shown to counteract the inhibitory effect of indomethacin and aspirin on the cyclooxygenase enzyme system in seminal vesicle microsomes and in platelets and vascular tissue. The hypothesis that the mechanism of salicylic acid "protection" against indomethacin-induced gastric lesions involves interference with indomethacin-induced mucosal cyclooxygenase inhibition was tested. Male, fasted rats were treated with intragastric salicylic acid in doses of 50, 100, 200, 300, or 400 mg/kg concomitantly with a sc injection of 20 mg/kg of indomethacin. Gastric mucosal lesions and mucosal cyclooxygenase activity (as measured by ex vivo prostaglandin F2 alpha synthesis) were examined 3 hr later. Intragastric salicylic acid, 200-400 mg/kg, significantly reduced indomethacin-induced lesion formation, while counteracting significantly indomethacin inhibition of prostaglandin synthesis. Salicylic acid alone did not significantly change cyclooxygenase activity. It is concluded that topical salicylic acid can decrease indomethacin-induced gastric mucosal lesion in the rat, in part, by counteracting the inhibitory effect of indomethacin at the cyclooxygenase level.

Animals↗

Identification and determination of salicylic acid and salicyluric acid in urine of people not taking salicylate drugs.

BACKGROUND: Salicylic acid (SA) is present in the serum of people who have not taken salicylate drugs. Now we have examined the urine of these subjects and found that it contains SA and salicyluric acid (SU). We have established the identities of these phenolic acids and determined their concentrations. METHODS AND RESULTS: The acidic hydrophobic compounds of urine were separated using high-performance liquid chromatography (HPLC) and were detected and quantified electrochemically. Two approaches were used to establish the identity of SA and SU. First, the retention times (Rt) of the substances extracted and those of SA and SU were compared under two sets of chromatographic conditions; the Rt of the compounds suspected to be SA and SU and those of the authentic substances were very similar under both sets of conditions. Second, the unknown substances, isolated by HPLC, were treated with acetyl chloride in methanol and compared with the methyl esters of SA and SU by using gas chromatography-mass spectrometry; the unknown compounds after esterification had very similar mass spectra and gas chromatographic R, to those of methyl salicylate and methyl salicylurate. The median (n = 10) urinary concentration of SA was 0.56 micromol/L (range 0.07-0.89 micromol/L) and that of SU was 3.20 micromol/L (range 1.32-6.54 micromol/L). SA and its major urinary metabolite, SU, were found in the urine of all of the 10 people examined.

Adolescent↗

[Development of salicylic acid dipstick test].

A dipstick test was successfully devised for the screening of salicylic acid in urine. It, named "salicylic acid dipstick test", is TLC plastic sheet which was soaked into 5% (w/v) of ferric chloride aqueous solution, then was covered with Oblate and dried. The test paper was dipped into the sample, then it immediately turned purple under the condition of more than 100 microg/ml of salicylic acid in urine. This device was useful for the emergency screening of salicylic acid in acute poisoning cases with aspirin.

Adult↗

Free and conjugated benzoic acid in tobacco plants and cell cultures. Induced accumulation upon elicitation of defense responses and role as salicylic acid precursors.

Salicylic acid (SA) is a key endogenous component of local and systemic disease resistance in plants. In this study, we investigated the role of benzoic acid (BA) as precursor of SA biosynthesis in tobacco (Nicotiana tabacum cv Samsun NN) plants undergoing a hypersensitive response following infection with tobacco mosaic virus or in tobacco cell suspensions elicited with beta-megaspermin, an elicitor from Phytophthora megasperma. We found a small pool of conjugated BA in healthy leaves and untreated cell suspensions of tobacco, whereas free BA levels were barely detectable. Infection of plants with tobacco mosaic virus or elicitation of cells led to a rapid de novo synthesis and accumulation of conjugated BA, whereas free BA was weakly induced. In presence of diphenylene iodonium, an inhibitor of superoxide anion formation, SA accumulation was abolished in elicited cells and much higher BA levels were concomitantly induced, mainly as a conjugated form. Furthermore, piperonylic acid, an inhibitor of cinnamate-4-hydroxylase was used as a powerful tool to redirect the metabolic flow from the main phenylpropanoid pathway into the SA biosynthetic branch. Under these conditions, in vivo labeling and radioisotope dilution experiments with [(14)C]trans-cinnamic acid as precursor clearly indicated that the free form of BA produced in elicited tobacco cells is not the major precursor of SA biosynthesis. The main conjugated form of BA accumulating after elicitation of tobacco cells was identified for the first time as benzoyl-glucose. Our data point to the likely role of conjugated forms of BA in SA biosynthesis.

Benzoates↗

Benzoic acid inhibits peach root growth and lateral root emergence by disrupting auxin homeostasis through salicylic acid accumulation.

We established a non-sterile root transformation system in peach seedlings. Using this system, we demonstrated that BA treatment inhibits plant growth and lateral root emergence by SA-mediated disruption of auxin distribution. Allelopathic autotoxins, particularly benzoic acid (BA), are recognized as primary contributors to peach (Prunus persica) replant disease; however, the molecular mechanisms by which BA disrupts root development remain poorly understood. BA treatment significantly reduced stem and root length and inhibited lateral root emergence without affecting lateral root initiation. To investigate the underlying mechanism at cellular resolution, we established a non-sterile Agrobacterium rhizogenes-based root transformation system achieving 27.11% transformation efficiency. Auxin biosynthesis (PpYUC10), influx transport (PpAUX1), and response (PpARF19) genes were markedly downregulated following BA treatment. Transgenic roots expressing the DR5::GUS auxin reporter exhibited reduced DR5 activity in root tips and suppressed expression in tissues surrounding lateral root primordia, indicating impaired auxin signaling at both developmental sites. Hormone profiling revealed a non-significant trend toward reduced auxin metabolites alongside significant accumulation of salicylic acid (SA), an auxin-antagonistic hormone, and its storage conjugate SA 2-O-β-glucoside. Supporting a causal role for SA, exogenous SA phenocopied BA-induced root growth inhibition, whereas co-treatment with IAA or the SA-biosynthesis inhibitor aminoindan-1-phosphonic acid (AIP) significantly rescued lateral root number and root fresh weight. Multi-treatment RNA-seq identified "response to auxin" and "response to salicylic acid" as the most enriched GO terms in BA-treated roots, and AIP treatment restored the expression of key auxin-related genes while reversing BA-induced SA-pathway changes. Together, these findings suggest that BA-induced SA accumulation suppresses auxin biosynthesis, transport, and signaling, thereby inhibiting peach root growth and lateral root emergence. This study elucidates the molecular basis of BA autotoxicity and establishes a transformation platform for functional genomic studies in Prunus.

Indoleacetic Acids↗

Distribution kinetics of salicylic acid in the isolated perfused rat liver assessed using moment analysis and the two-compartment axial dispersion model.

The distribution kinetics of salicylic acid in the single-pass isolated perfused rat liver has been investigated under varying conditions of perfusate flow (15 to 30 ml min-1) and of salicylate perfusate concentration (0, 100, 200 mg l-1) using statistical moment analysis and the two-compartment axial dispersion model. Salicylic acid was not metabolised during the experiment. The perfusate did not contain binding protein. As flow rate was increased, the maximum fraction output per second (f(t)max) increased and the mean transit time (MTTH) decreased, while tmax became shorter for both tritiated water and 14C-salicylic acid. Increasing the salicylate perfusate concentration profoundly affected the frequency outflow profile of 14C-salicylic acid, but not that of tritiated water. The one-compartment axial dispersion model adequately described the frequency outflow profile for tritiated water, whereas the two-compartment form, which incorporates a cellular permeability barrier, provided a better description of the 14C-salicylic acid outflow data. The estimated two-compartment axial dispersion model parameters for 14C-salicylic acid, DN, the dispersion number (0.08 +/- 0.03), k12, the influx rate constant (0.56 +/- 0.04 sec-1) and k21, the efflux rate constant (0.095 +/- 0.01 sec-1) were independent of perfusate flow rate. The in situ permeability-surface area product for 14C-salicylic acid (4.6 +/- 0.7 ml min-1g-1 liver) was in good agreement with literature estimates obtained from in vitro hepatocyte experiments, suggesting that the permeability barrier is at the hepatocyte membrane. Whereas DN and k12 were uninfluenced by, k21 displayed a positive correlation with, salicylate perfusate concentration. This correlation was most likely due to decreased intracellular salicylate binding.

Animals↗

Salicylic acid permeability properties of the rabbit cortical collecting duct.

To assess the role of nonionic diffusion of salicylic acid (pKa = 3) in the terminal nephron, we measured the passive permeability of [14C]salicylic acid in rabbit cortical collecting ducts isolated and perfused in vitro. This segment can produce and maintain a maximal pH gradient between blood and tubular fluid. When peritubular pH was kept constant at pH 7.4 the apparent permeability of salicylic acid (P', 10(-6) cm/s) was 6.2 +/- 1.1 at a luminal pH of 6.0, 17.2 +/- 5.3 at a luminal pH of 5.5, and 39.0 +/- 4.7 at a luminal pH of 5.0. These permeabilities were in close correlation with the percentage of nonionized salicylic acid present at each pH, indicating that only the nonionized molecule can diffuse across the collecting duct epithelium. By recalculating the permeability, taking into account only the concentration of the nonionized salicylic acid molecules, we obtained the apparent permeability of nonionized salicylic acid, which was no longer pH dependent and averaged 4,345 +/- 460 x 10(-6) cm/s. The apparent activation energy of this diffusion process was 9.3 +/- 1.2 kcal/mol as calculated from an Arrhenius plot.

Absorption↗