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Results for “SALICYLIC ACID”

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PubMed1992

Nonionic diffusion of salicylic acid through MDCK cell monolayers.

MDCK-I cells, grown on collagen-coated filters, were used as a model of the distal nephron to study the nonionic diffusion of salicylic acid. The apparent transcellular permeability (PSal, centimeters per second) and intracellular content (ContSal, picomoles) of [14C]salicylic acid (ionized and nonionized) were measured from both apical-to-basolateral and basolateral-to-apical unidirectional fluxes. During the measurement of apical-to-basolateral fluxes at 21 degrees C, both PSal and ContSal correlated directly with the proportion of nonionized salicylic acid in the apical medium over the pH range 6.0-7.4. This indicated that the observed permeability was due to pure nonionic diffusion. However, in the basolateral-to-apical direction, the correlation was less evident and ContSal was 10 to 20 times higher, although PSal was of the same magnitude. These observations could not be explained by facilitated transport of anionic salicylic acid, at 21 degrees C, because 1 mM probenecid, 1 mM p-aminohippurate and 1 mM cold salicylic acid did not abolish the higher intracellular content obtained during basolateral-to-apical fluxes. Raising the temperature produced only a gradual increase of PSal measured in the basolateral-to-apical direction and an unexpected decrease of ContSal. Because basolateral-to-apical facilitated transport does not play a significant role, the most plausible reason for the higher ContSal during basolateral-to-apical fluxes is that the apical membrane possesses a much lower (10- to 20-fold less) salicylic acid permeability than the basolateral membrane and constitutes the rate-limiting step for transcellular salicylic acid flux.

Animals↗

PubMed1988

The relevance of salicylic acid in the treatment of plaque psoriasis with dithranol creams.

The relevance of salicylic acid in dithranol creams was evaluated in a double-blind study. Patients with chronic plaque psoriasis were treated using a short-contact schedule for dithranol on an outpatient basis. A left-right comparison was carried out between sites treated with either dithranol with 2% salicylic acid (D + S) or dithranol in the same base without salicylic acid (D-S). Clinical results were evaluated once a week using the psoriasis area severity index. In order to quantify the improvement, flow cytometric measurements were done using the monoclonal antibody Ks8.12, recognizing keratin 16 in normal and lesional epidermis. Simultaneously, relative DNA content was quantified which previously was described as a useful method to monitor a therapeutic effect. Both PASI scores and Ks8.12 binding decreased after 6 weeks treatment with D + S and D-S. However, percentages of cells in SG2M phases did not show a significant change. No significant difference was observed between sites treated with either D + S or D-S. Therefore we conclude that the addition of salicylic acid in a concentration of 2% does not enhance the efficacy of dithranol creams and we confirm that Ks8.12 is a useful quantitative marker for therapeutic efficacy.

Adolescent↗

PubMed1996

The effect of protein binding on the deep tissue penetration and efflux of dermally applied salicylic acid, lidocaine and diazepam in the perfused rat hindlimb.

Doses of radiolabeled water, salicylic acid, lidocaine and diazepam were applied in 2 ml of phosphate buffer saline to the exposed dermis on the thigh of a perfused rat hindlimb. Hindlimbs were perfused with Krebs-Heinseleit buffer at 37 degrees C containing 4% albumin or 2.5% dextran 40 at a constant rate of 4 ml/min. Clearance of solutes from dermal sites was monitored by frequent sampling at the dermal site and of the outflowing perfusate. In addition, the concentration of solutes in the various tissues below the treated and contralateral sites were determined at the end of a perfusion after dissection, solubilization and scintillation counting of the individual tissues. Estimates of the absorption rate constant from the dermis and the elimination rate constant from the perfused limb were made by the simultaneous fitting of absorption and efflux data with a one-compartmental pharmacokinetic model. Diazepam was cleared fastest through the dermis, followed by water, salicylic acid and lidocaine. The efflux of diazepam and salicylic acid from the hindlimb was significantly enhanced by the presence of albumin in the perfusate relative to no albumin (P < .05), whereas the efflux of water and lidocaine were unaffected by changes in albumin content. Analysis of individual tissues at the end of the perfusion showed that water had the highest relative tissue concentrations with diazepam the least, high concentrations appearing to partition into and remain associated with the dermis. The presence of albumin in the perfusate significantly increased the concentration of diazepam found in contralateral skin samples (P < .05) and showed the same trend for salicylic acid and lidocaine. These findings show that protein binding significantly affects the deep tissue penetration and distribution of dermally applied solutes and that this effect is more prominent for highly protein-bound solutes.

Administration, Cutaneous↗

PubMed2003

Target genes for OBP3, a Dof transcription factor, include novel basic helix-loop-helix domain proteins inducible by salicylic acid.

Overexpression of a salicylic-acid (SA)-inducible Arabidopsis DNA binding with one finger (Dof) transcription factor, called OBF-binding protein 3 (OBP3; AtDof3.6), has previously been shown to result in growth defects. In this study, suppressive subtraction hybridization (SSH) was used to isolate genes induced in an OBP3-overexpression line and several putative clones, called OBP3-responsive genes (ORGs), were isolated. The link with the induced expression levels of these genes and OBP3 overexpression was confirmed by analysing additional OBP3-overexpression lines. ORG1 through ORG4 are novel genes, while ORG5 is an extensin gene, AtExt1. While ORG4 has no similarity with other proteins in the database, ORG1 has weak similarity in different regions of the predicted protein with CDC2 and fibrillin. ORG2 and ORG3 share 80% overall identity in their deduced amino acid sequences and contain a basic helix-loop-helix DNA-binding domain, suggesting that ORG2 and ORG3 may be transcription factors. The expression of the ORG1, ORG2 and ORG3 genes was co-regulated under all conditions examined including upregulation by SA and downregulation by jasmonic acid (JA). Fifteen OBP3-silenced lines were generated to further explore the function of OBP3. Although there were no visible phenotypic changes in any of these lines, the expression of ORG1, ORG2 and ORG3 was reduced. Among the ORG genes, ORG1, ORG2 and ORG3 contained the highest number of potential Dof-binding sites in the promoter region, and their expression was significantly increased within 3 h after induction of OBP3 expression using an inducible promoter system, and closely reflected the expression levels of the exogenous OBP3 protein. The results from the gain-of-function and loss-of-function experiments suggest that the ORG1, ORG2 and ORG3 genes are direct target genes of OBP3.

Amino Acid Sequence↗

PubMed1987

In vivo measurement of the keratolytic effect of salicylic acid in three ointment formulations.

The release and activity of salicylic acid from different ointment formulations was studied in vivo by staining the horny layer with silver nitrate and measuring the light reflectance profile over 56 h, after application of the ointment for 4 h. The peeling effect of an ointment containing 5% salicylic acid and 10% urea was tested and compared with 5% and 10% salicylic acid in petrolatum. It was shown that shedding from the stained sites was faster with the urea-containing preparation than with the classic petrolatum ointments. The method described can be used to assess the bioavailability of keratolytic agents incorporated in topical formulations.

Biological Availability↗

PubMed2001

Incorporation of salicylic acid derivatives to hydrophilic copolymer systems with biomedical applications.

Hydrogels based on polymeric derivatives of salicylic acid have been prepared for biomedical applications by free radical copolymerization of 2-hydroxy-4-methacrylamidobenzoic acid, 4HMA, and 2-hydroxy-5-methacrylamidobenzoic acid, 5HMA, with 2- hydroxyethylmethacrylate, HEMA, in a wide range of compositions. The reactivity ratios of 4HMA and 5HMA with HEMA in radical copolymerization processes have been determined from their 1H NMR spectra by applying linearization methods and non-linear least square treatments. Tgs of the corresponding copolymers were analyzed by DSC. The swelling behavior in water of the prepared copolymers was studied in comparison to poly-(HEMA), poly-(4HMA) and poly-(5HMA) hydration degrees, being in all cases superior to 35%. The hydrolytical behavior of the synthesized copolymers was studied at three different pHs (2, 7.4 and 10) determining the release percentage of the salicylic acid derivatives, 4-amino salicylic acid, 4ASA, and 5-amino salicylic acid, 5ASA, analyzed by high performance liquid chromatography (HPLC). The release analysis was followed during 230 days and a pH dependence was observed obtaining the highest release percentages at pH=10, whereas at physiological pH (7.4) the release percentages were in range from 2 to 5% at that time for all copolymer systems. The hydrolytical stability is enough for long-term applications like bone cements, ionomers, etc.

Journal Article↗

PubMed2004

Synthesis, X-ray crystal structure, anti-fungal and anti-cancer activity of [Ag2(NH3)2(salH)2] (salH2=salicylic acid).

[Ag(2)(NH(3))(2)(salH)(2)] (salH(2)=salicylic acid) was synthesised from salicylic acid and Ag(2)O in concentrated aqueous NH(3) and the dimeric Ag(I) complex was characterised using X-ray crystallography. The complex is centrosymmetric with each metal coordinated to a salicylate carboxylate oxygen and to an ammonia nitrogen atom in an almost linear fashion. The two [Ag(NH(3))(salH)] units in the complex are linked by an Ag-Ag bond. Whilst metal-free salH(2) did not prevent the growth of the fungal pathogen Candida albicans [Ag(2)(NH(3))(2)(salH)(2)], [Ag(2)(salH)(2)] and some simple Ag(I) salts greatly inhibited cell reproduction. SalH(2), [Ag(2)(NH(3))(2)(salH)(2)] [Ag(2)(salH)(2)] and AgClO(4) produced a dose-dependent cytotoxic response against the three human derived cancer cell lines, Cal-27, Hep-G2 and A-498, with the Ag(I)-containing reagents being the most effective.

Animals↗

PubMed2003

Urinary excretion of salicyluric and salicylic acids by non-vegetarians, vegetarians, and patients taking low dose aspirin.

AIM: To compare amounts of salicyluric acid (SU) and salicylic acid (SA) excreted daily in the urine of non-vegetarians and vegetarians not taking salicylate drugs, and patients taking 75 or 150 mg aspirin/day. METHODS: Urine excreted over 24 hours was collected from volunteers in the four groups. The volumes were recorded and the concentrations of SU and SA were determined electrochemically after separation by high performance liquid chromatography. RESULTS: Significantly more SU was excreted daily by vegetarians (median, 11.01; range, 4.98-26.60 micro mol/24 hours) than by non-vegetarians (median, 3.91; range, 0.87-12.23 micro mol/24 hours), although amounts were significantly lower than those excreted by patients taking aspirin. Median amounts of SU excreted by patients taking 75 and 150 mg/day of low dose aspirin were 170.69 (range, 13.15-377.18) micro mol/24 hours and 165.17 (range, 5.61-429.12) micro mol/24 hours, respectively. The amount of SU excreted by patients taking either 75 or 150 mg of aspirin/day was not significantly different. Significantly more SA was excreted by vegetarians (median, 1.19; range, 0.02-3.55 micro mol/24 hours) than by non-vegetarians (median, 0.31; range, 0.01-2.01 micro mol/24 hours). The median amounts of SA excreted by vegetarians and the patients taking aspirin were not significantly different. CONCLUSIONS: More SU and SA is excreted in the urine of vegetarians than in non-vegetarians, consistent with the observation that fruits and vegetables are important sources of dietary salicylates. However, significantly less SU was excreted by vegetarians than patients taking aspirin, indicating that the daily intake of bioavailable salicylates by vegetarians is considerably lower than that supplied by a single 75 or 150 mg dose of aspirin.

Adolescent↗

PubMed2005

Oxidation of anthracyclines by peroxidase metabolites of salicylic Acid.

Oxidation of anthracyclines leads to their degradation and inactivation. This process is carried out by peroxidases in the presence of a catalytic cofactor, a good peroxidase substrate. Here, we investigated the effect of salicylic acid, a commonly used anti-inflammatory and analgesic agent, on the peroxidative metabolism of anthracyclines. We report that at pharmacologically relevant concentrations, salicylic acid stimulates oxidation of daunorubicin and doxorubicin by myeloperoxidase and lactoperoxidase systems and that efficacy of the process increases markedly on changing the pH from 7 to 5. This pH dependence is positively correlated with the ease with which salicylic acid itself undergoes metabolic oxidation and involves the neutral form of the acid (pKa = 2.98). When salicylic acid reacted with a peroxidase and H2O2 at acid pH (anthracyclines omitted), a new metabolite with absorption maximum at 412 nm was formed. This metabolite reacted with anthracyclines causing their oxidation. It was tentatively assigned to biphenyl quinone, formed by oxidation of biphenol produced by dimerization of salicylic acid-derived phenoxyl radicals. The formation of this product was inhibited in a concentration-dependent manner by the anthracyclines, suggesting their scavenging of the salicylate phenoxyl radicals. Altogether, this study demonstrates that oxidation of anthracyclines is mediated by peroxidase metabolites of salicylic acid, such as phenoxyl radicals and the biphenol quinone. Given that cancer patients undergoing anthracycline chemotherapy may be administered salicylic acid-based drugs to control pain and fever, our results suggest that liberated salicylic acid could interfere with anticancer and/or cardiotoxic actions of the anthracyclines.

Anthracyclines↗

PubMed2005

Cutaneous bioassay of salicylic acid as a keratolytic.

Keratolytic efficacy of topical preparations containing salicylic acid was studied in humans utilizing adhesive tape stripping and quantifying SC removal by protein analysis. In combination with tape stripping, squamometry was used to evaluate the influence of salicylic acid on skin surface scaliness and desquamation. Furthermore, skin barrier perturbation and skin irritancy was recorded and related to the dermatopharmacological effect of the preparations. In contrast to squamometry, tape stripping combined with protein analysis was sensitive in detecting keratolytic effect of salicylic acid within hours of application. Importantly, whereas the pH of the preparations only minimally influenced efficacy, local dermatotoxicity was significantly increased at acidic pH. This indicates that the quest to increase the amount of free, non-dissociated SA is, in fact, counterproductive as the more acidic preparations resulted in skin irritation and barrier disruption.

Administration, Cutaneous↗

PubMed1984

Disposition of salicylic acid in analbuminemic rats.

To clarify the role of albumin in the dispositions of drugs by in vivo experiment, analbuminemic rats were used and plasma-level analyses and whole-body autoradiography following intravenous administration of 14C-salicylic acid were carried out. The distribution volume of salicylic acid in analbuminemic rats (650 +/- 33 ml/kg) was remarkably larger than that in normal rats (180 +/- 3 ml/kg) (p less than 0.01). Whole-body autoradiograms demonstrated that transfer of salicylic acid from the blood to the liver, muscle and brain, especially to the liver, may be increased in analbuminemic rats. The increased distribution may be explained by the lack of plasma albumin, since the distribution of salicylic acid depends in part on plasma albumin binding. The total body clearance of salicylic acid in analbuminemic rats (12.2 +/- 1.4 ml/min/kg) was about 3.2 times that in normal rats (3.8 +/- 0.1 ml/min/kg) (p less than 0.01), suggesting that metabolic clearance and/or renal clearance is enhanced in analbuminemic rats. Increased extraction by the liver and/or the kidney due to increased free fraction in total (bound and unbound) plasma salicylic acid assumed to be responsible for this result.

Animals↗

PubMed1999

Ozone-induced cell death occurs via two distinct mechanisms in Arabidopsis: the role of salicylic acid.

Previous studies suggest that salicylic acid (SA) plays an important role in influencing plant resistance to ozone (O3). To further define the role of SA in O3-induced responses, we compared the responses of two Arabidopsis genotypes that accumulate different amounts of SA in response to O3 and a SA-deficient transgenic Col-0 line expressing salicylate hydroxylase (NahG). The differences observed in O3-induced changes in SA levels, the accumulation of active oxygen species, defense gene expression, and the kinetics and severity of lesion formation indicate that SA influences O3 tolerance via two distinct mechanisms. Detailed analyses indicated that features associated with a hypersensitive response (HR) were significantly greater in O3-exposed Cvi-0 than in Col-0, and that NahG plants failed to exhibit these HR-like responses. Furthermore, O3-induced antioxidant defenses, including the redox state of glutathione, were greatly reduced in NahG plants compared to Col-0 and Cvi-0. This suggests that O3-induced cell death in NahG plants is due to the loss of SA-mediated potentiation of antioxidant defenses, while O3-induced cell death in Cvi-0 is due to activation of a HR. This hypothesis is supported by the observation that inhibition of NADPH-oxidases reduced O3-induced H2O2 levels and the O3-induced cell death in Cvi-0, while no major changes were observed in NahG plants. We conclude that although SA is required to maintain the cellular redox state and potentiate defense responses in O3 exposed plants, high levels of SA also potentiate activation of an oxidative burst and a cell death pathway that results in apparent O3 sensitivity.

Antioxidants↗

PubMed1969

The kinetics of elimination of salicylic acid and the formation of gentisic acid.

1. A method for the estimation of gentisic acid in urine has been devised which is based on thin-layer chromatography and fluorimetry.2. In man the urinary excretion of gentisic acid accounted for 0.6% of a 0.32 g dose of aspirin and 1.1% of a 1.28 g dose. The increase in the percentage of the dose excreted as gentisic acid provides further evidence that the elimination of salicylic acid cannot be entirely described by first order kinetics.3. Equations are presented which describe the amount of gentisic acid formed from various doses of salicylic acid in a model system, when elimination proceeds partly by simultaneous first order and zero order kinetics. The close agreement of the experimental and theoretical results indicates that the model provides an acceptable interpretation of salicylic acid elimination in man.

Aspirin↗

PubMed2005

Topical salicylic acid gel as a treatment for molluscum contagiosum in children.

OBJECTIVE: To determine if the application of salicylic acid gel or phenol solution affected resolution of molluscum contagiosum (MC) lesions in children. PATIENTS AND METHODS: This was a randomized, prospective controlled trial with two treatment arms and one vehicle arm for treatment of MC in children. The trial was set in the dermatology outpatient clinics of a teaching hospital and a district general hospital. A total of 114 children were enrolled in the study (age range 1-15 years) over a 4-year period; 83 of the children completed the study. Patients were randomized to receive one of three possible treatments: monthly vehicle application of 70% alcohol, monthly application of 10% phenol in 70% alcohol once or twice weekly 12% salicylic acid gel. All patients also received treatment with daily aqueous cream to reduce eczema. They returned monthly to the clinic for treatment and counting of MC lesions. They were reviewed either until complete resolution or up to 6 months, whichever occurred sooner. The main outcome measure was the time taken for complete resolution of MC lesions. RESULTS: In the intention-to-treat analysis there was no difference between treatment arms when the 31 non-completers were analysed as failures (log-rank test: p = 0.38). In an 'as treated' analysis, 16 of 27 children (59.2%: 95% confidence interval 30.2-88.3) had cleared with vehicle, 18 of 32 (56.3%, 30.3-82.2) with phenol solution and 21 of 24 (87.5%, 50.1-124.9) with salicylic acid gel (log-rank test: p = 0.03). On an as treated basis, salicylic acid was significantly better at clearing MC than dilute phenol (p = 0.006). The treatment in all groups was very well tolerated or acceptable in 93% of children. CONCLUSION: Our results suggest that topical salicylic acid may be beneficial in speeding resolution of MC in children. Dilute phenol application does not appear to affect the disease course.

Administration, Topical↗

PubMedDate not supplied

Method for the extraction of the volatile compound salicylic acid from tobacco leaf material.

Salicylic acid (SA) is a signalling compound in plants which is able to induce systemic acquired resistance. In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. This is mainly caused by sublimation of SA, especially during evaporation of organic solvents. Techniques have been designed in order to overcome this problem. In the first part of the extraction procedure, sublimation of SA was prevented by addition of 0.2 M sodium hydroxide. At a later stage of the extraction procedure, sublimation of SA during solvent evaporation was controlled by the addition of a small amount of HPLC eluent. In this way, recoveries in the range of 71-91% for free SA and 65-79% for acid-hydrolysed SA were obtained. Recoveries could be further optimised by the use of an internal standard to correct for volume changes after the addition of the HPLC eluent.

Acetates↗

PubMed1996

Rapid high-performance liquid chromatographic assay for salicylic acid in plasma without solvent extraction.

The in vivo measurement of highly reactive free radicals, such as the hydroxyl radical (oOH), in humans is very difficult, if not impossible. Specific markers, based on the ability of oOH to attack aromatic molecules and produce hydroxylated compounds, are under investigation. In vivo radical metabolism of salicylic acid produces two main hydroxylated derivatives: 2,3- and 2,5-dihydroxybenzoic acid (DHBA). The measurement of 2,3-DHBA, following oral administration of salicylic acid or its acetylated form (aspirin), is proposed for the assessment of in vivo oxidative stress. The intensity of oxidative stress is a function of the ratio of dihydroxylated derivatives to salicylic acid rather than the absolute dihydroxylated derivatives levels. Consequently, a simple, accurate, and sensitive assay of the salicylic acid level in plasma is needed to investigate the in vivo free radical production. In this work, a rapid and sensitive method is presented that is useful for the quantitation of salicylic acid in biological fluids. The methodology uses high-performance liquid chromatography with spectrophotometric detection for the identification and quantitation of salicylic acid without organic extraction. A detection limit of less than 5 mumol is achieved with spectrophotometric detector responses that are linear over at least 6 orders of magnitude. Plasma concentrations of salicylic acid determined by the present technique are reported following the administration of 1000 mg aspirin in 20 healthy subjects.

Chromatography, High Pressure Liquid↗

PubMed1978

Effect of salicylic acid on the percutaneous absorption of hydrocortisone. In vivo studies in the rhesus monkey.

To document the effect of salicylic acid on hydrocortisone penetration in vivo in the rhesus monkey, hydrocortisone 14C, with and without salicylic acid, was applied in acetone and the solvent evaporated. The compounds also were applied in a formulation (60% ethanol, 5% propylene glycol, 5% glycerin, 30% water) in which salicylic acid enhances penetration in vitro. There was a difference in the kinetics of hydrocortisone absorption with the two formulations. In acetone, excretion of 14C peaked at 48 hours and then declined. With the other formulation, excretion peaked at 48 hours, maintained to 72 hours, and then declined. There was no statistical difference in the percutaneous absorption of hydrocortisone with the addition of salicylic acid. These in vivo data are in contrast to the reported enhancing effect of salicylic acid obtained with in vitro studies.

Animals↗

PubMed2000

Nitric oxide and salicylic acid signaling in plant defense.

Salicylic acid (SA) plays a critical signaling role in the activation of plant defense responses after pathogen attack. We have identified several potential components of the SA signaling pathway, including (i) the H(2)O(2)-scavenging enzymes catalase and ascorbate peroxidase, (ii) a high affinity SA-binding protein (SABP2), (iii) a SA-inducible protein kinase (SIPK), (iv) NPR1, an ankyrin repeat-containing protein that exhibits limited homology to IkappaBalpha and is required for SA signaling, and (v) members of the TGA/OBF family of bZIP transcription factors. These bZIP factors physically interact with NPR1 and bind the SA-responsive element in promoters of several defense genes, such as the pathogenesis-related 1 gene (PR-1). Recent studies have demonstrated that nitric oxide (NO) is another signal that activates defense responses after pathogen attack. NO has been shown to play a critical role in the activation of innate immune and inflammatory responses in animals. Increases in NO synthase (NOS)-like activity occurred in resistant but not susceptible tobacco after infection with tobacco mosaic virus. Here we demonstrate that this increase in activity participates in PR-1 gene induction. Two signaling molecules, cGMP and cyclic ADP ribose (cADPR), which function downstream of NO in animals, also appear to mediate plant defense gene activation (e.g., PR-1). Additionally, NO may activate PR-1 expression via an NO-dependent, cADPR-independent pathway. Several targets of NO in animals, including guanylate cyclase, aconitase, and mitogen-activated protein kinases (e.g., SIPK), are also modulated by NO in plants. Thus, at least portions of NO signaling pathways appear to be shared between plants and animals.

Adenosine Diphosphate Ribose↗