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[Free and conjugated forms of salicylic acid: content and role in potato].

Hydrolysis of conjugated forms of salicylic acid and accumulation of its free form was observed after infection of potato tubers (Solanum tuberosum L.) with an incompatible race of phytophthora or treatment with an elicitor (chitosan). Infection of tubers with a compatible race of the pathogen or treatment with a suppressor (laminarin) decreased both the degree of hydrolysis of conjugated forms of salicylic acid and the accumulation of its free form.

Chitosan↗

Induction of UDP-Glucose:Salicylic Acid Glucosyltransferase in Oat Roots.

A UDP-glucose:salicylic acid 3-O-glucosyltransferase (EC 2.4.1.35) (GTase) from oat (Avena sativa L. cv Dal) root extracts was assayed in vitro using [(14)C]salicylic acid (SA) and an ion exchange column to separate SA from beta-glucosylsalicylic acid. The GTase, present at a very low constitutive level, was inducible to 23 times the constitutive level. When excised roots were exposed to SA at pH 6.5, the specific activity of the enzyme increased within 1.5 h, peaked after 8 to 10 h, and then declined. The increase in specific activity depended on the concentration of SA in the induction medium. Among 16 phenolics and phenolic derivatives tested, GTase induction showed high specificity toward SA and acetylsalicylic acid. Specific activity of the enzyme was induced to higher levels in roots from 7-d-old seedlings than roots from younger plants. GTase activity was less inducible in basal compared with median or apical root sections. Induction of GTase activity was a result of de novo RNA and protein synthesis. Candidate peptides for the GTase were identified by comparison of two-dimensional electrophoresis gels of proteins labeled with [(35)S]methionine during incubation of roots in the presence or the absence of SA and a gel of a partially purified GTase preparation.

Journal Article↗

The effect of ageing on plasma albumin and plasma protein binding of diazepam, salicylic acid and digitoxin in healthy subjects and patients with renal impairment.

1. Plasma albumin concentration was measured in 118 healthy subjects (aged between 18 and 87 years), in 95 renal patients with creatinine clearances between 15 and 50 ml min-1 (aged between 14 and 79 years) and in 101 uraemic patients maintained on chronic haemodialysis (aged between 27 and 83 years). 2. There was a significant (P less than 0.001) negative correlation between albumin concentration and age in healthy subjects, but no correlation in patients with low creatinine clearance or in uraemic patients. 3. The ex vivo plasma binding of diazepam (1 microM), salicylic acid (2 mM) and digitoxin (37 nM) was studied in groups of age-selected young and aged healthy subjects in patients with low creatinine clearance and in patients with uraemia. The unbound fractions of diazepam and salicylic acid were about double in old compared with young healthy subjects whereas they were similar in young and old patients with lowered creatinine clearance. In uraemic patients, ageing did not affect the binding of salicylic acid whereas the unbound fraction of diazepam was slightly but significantly greater in elderly subjects. The unbound fraction of digitoxin was independent of age in both healthy subjects and in those with renal disease. 4. Decreased plasma binding of diazepam and salicylic acid was partially corrected by extensive dialysis of plasma. The lower plasma binding of diazepam and salicylic acid associated with ageing may be ascribed to the effects of endogenous displacers and to hypoalbuminaemia. The influence of these two factors appears to be drug-dependent.

Adolescent↗

Iron metabolism in Pseudomonas: salicylic acid, a siderophore of Pseudomonas fluorescens CHAO.

Under iron-starvation conditions of growth, Pseudomonas fluorescens CHA0, a soil isolate involved in phytopathogenic fungi antagonisms, produced, together with pyoverdine, a second iron-chelating compound which was purified and identified by spectroscopy, HPLC and 1H-NMR to be salicylic acid. Mutants unable to synthesize pyoverdine overproduced this compound by a factor of 9-14. The biosynthesis of salicylic acid was under iron control; it was fully inhibited by 5 microM added iron in the growth medium. In contrast, salicylic acid of either bacterial or commercial origin facilitated labeled iron incorporation in iron-starved cells. Based on these two relationships observed with bacterial iron metabolism it is concluded that salicylic acid has a siderophore function for this strain.

Iron↗

The study on the biological fate of paraben at the dose of practical usage in rat. III. The effects of salicylic acid on the fate of ethyl paraben.

The biological fates of ethyl paraben were investigated after the simultaneous administration with salicylic acid. Those fates were compared with those of ethyl paraben alone obtained in the previous experiments. The biological fates of ethyl paraben after the simultaneous administration with salicylic acid were different from those of ethyl paraben alone as reported in the previous reports. The excretion of unconjugated p-hydroxybenzoic acid, which is a hydrolyzed product of ethyl paraben, increased and those of p-hydroxyhippuric acid, glycine conjugate of p-hydroxybenzoic acid, and p-hydroxybenzoyl glucuronide, its ester type glucuronide, decreased. The blood concentration patterns were considerably different from those of ethyl paraben alone, especially the elimination of every metabolite was delayed. Pharmacokinetic analyses on the data of blood concentration were carried out and the results also show the interaction of salicylic acid on the biological fate of ethyl paraben.

Animals↗

Improved colorimetric determination of salicylic acid and its metabolites in urine.

We describe an improvement in the Levy and Procknal method [J. Pharm. Sci. 57, 1330 (1968)] for determination of salicylic acid and its metabolites in urine. Salicylic acid and salicyluric acid are successively extracted from 1 or 2 ml of urine (acidified with HCl) by two 10-ml portions each of carbon tetrachloride and ethylene dichloride. The extracts of each solvent are shaken with 5 ml of ferric nitrate solution (a 10-fold dilution of 17 g of Fe(NO-3)-9H-2O in 1 liter of 70 mmol/liter HNO-3). The aqueous phases are centrifuged and their absorbances measured at 530 nm. For total salicylate, 3 ml of urine and 3 ml of HCl are heated in a partially evacuated serum vial at 100 degrees C for 16 h and then salicylic acid is assayed in the hydrolyzed sample. Recovery of a weighed oral dose of sodium salicylate in urine was 105.4%; it was 127.9% by the Levy and Procknal method for the same sample. The improved method is faster and more accurate.

Colorimetry↗

Treatment of acne vulgaris with salicylic acid pads.

Most cases of acne vulgaris are either mild or moderate in severity and well-suited for treatment with nonprescription agents that are safe, effective, and convenient to use. A review of four clinical studies and a comedolytic assay attests to the efficacy and safety of 0.5% and 2% solutions of salicylic acid for the treatment of acne vulgaris. In three placebo-controlled studies and a comedolytic assay, salicylic acid pads reduced the number of primary lesions and thereby the number and severity of all lesions associated with acne. Comparative studies of salicylic acid have shown it to be superior to benzoyl peroxide in reducing the total number of acne lesions. Adverse reactions to salicylic acid are generally limited to mild, local irritation occurring in a minority of patients.

Acne Vulgaris↗

Photophysics of intramolecularly hydrogen-bonded aromatic systems: ab initio exploration of the excited-state deactivation mechanisms of salicylic acid.

Excited state reaction paths and the corresponding energy profiles of salicylic acid have been determined with the CC2 method, which is a simplified version of singles-and-doubles coupled cluster theory. At crucial points of the potential energy hypersurfaces, single-point energy calculations have been performed with the CASPT2 method (second-order perturbation theory based on the complete active space self-consistent field reference). Hydrogen transfer along the intramolecular hydrogen bond as well as torsion and pyramidization of the carboxy group have been identified as the most relevant photochemical reaction coordinates. The keto-type planar S(1) state reached by barrierless intramolecular hydrogen transfer represents a local minimum of the S(1) energy surface, which is separated by a very low barrier from a reaction path leading to a low-lying S(1)-S(0) conical intersection via torsion and pyramidization of the carboxy group. The S(1)-S(0) conical intersection, which occurs for perpendicular geometry of the carboxy group, is a pure biradical. From the conical intersection, a barrierless reaction path steers the system back to the two known minima of the S(0) potential energy surface (rotamer I, rotamer II). A novel structure, 7-oxa-bicyclo[4.2.0]octa-1(6),2,4-triene-8,8-diol, has been identified as a possible transient intermediate in the photophysics of salicylic acid.

Computer Simulation↗

[The modes of anti-inflammatory and analgesic actions of aspirin and salicylic acid].

The modes of anti-inflammatory and analgesic actions of aspirin and salicylic acid were investigated using some experimental animal models. Anti-inflammatory potencies of aspirin were almost equal to those of sodium salicylate in the carrageenin hind paw edema, the cotton pellet granuloma and the adjuvant arthritis tests in rats. On the other hand, in the ultra-violet ray erythema and the arachidonic acid erythema tests in guinea pigs, aspirin was more potent than sodium salicylate. Aspirin and sodium salicylate exhibited almost the same inhibitions of the rat hind paw edema induced by a mixture of carrageenin and prostaglandin E1. These results suggest that inhibition of cyclo-oxygenase by aspirin does not play any important roles for the prevention of the vascular permeability increment and the granulation in the inflamed tissue. Aspirin may exert its antiinflammatory activity mainly as salicylic acid which is not an inhibitor of prostaglandins biosynthesis in vitro. Aspirin showed about 5 times more potent analgesic action than sodium salicylate in the lameness test using adjuvant arthritic rats. Analgesic potency of aspirin was decreased to the level of sodium salicylate by injection of prostaglandin E2 into the inflamed rat paw in the adjuvant-induced lameness test. On the other hand, analgesic potency of sodium salicylate was not decreased by the same treatment. It is concluded that aspirin has two analgesic effects on the inflammatory pain, one is inhibition of prostaglandins biosynthesis by acetylation of cyclo-oxygenase and the other is an action due to salicylic acid, but the action of salicylic acid was not totally explained by the inhibition of prostaglandins synthetase.

Animals↗

Flow-through UV spectrophotometric sensor for determination of (acetyl)salicylic acid in pharmaceutical preparations.

The solid phase spectrophotometry technique, in which the absorbance of the species of interest sorbed on a solid support is measured directly, was applied to the determination of salicylic acid using flow injection-analysis. Salicylic acid was determined by monitoring of its intrinsic absorbance at 297 nm sorbed on Sephadex QAE A-25 resin placed in an appropriate flow-through cell. The method proposed improves the selectivity compared with the corresponding solution-phase method and the sensitivity is increased by a factor of 30 or more. The flow-through sensor proposed allows working with several calibration lines simply by varying the sample volume injected. Thus, linear dynamic ranges from 1 to 20 and from 2 to 40 microg ml(-1) can be obtained by using 1000 and 300 microl, respectively, with detection limits being 0.064 and 0.135 microg ml(-1). Relative Standard Deviations (RSDs) of 0.52 and 0.38%, and sampling frequencies of 18 and 25 h(-1), respectively, were also achieved. The sensor also allows the indirect determination of acetylsalicylic acid previous hydrolysis on-line to salicylic acid. For acetylsalicylic acid, a linear dynamic range from 5 to 120 microg ml(-1) and 25 h(-1) of sampling frequency (300 microl of sample volume) were obtained. The proposed flow-through sensor has been successfully applied to the determination of both analytes in pharmaceutical preparations.

Anti-Inflammatory Agents, Non-Steroidal↗

Synthesis and cofluorescence of Eu(Y) complexes with salicylic acid and o-phenanthroline.

A series of dinuclear complexes of salicylic acid (HSal) and o-phenanthroline (Phen) with different molar ratios of Eu3+ to Y3+ have been synthesized. Their compositions are Eu(x)Y(1-x) (Sal)3(Phen) (x = 0 to approximately 1). Their UV spectra, IR spectra, and fluorescence spectra were studied. The UV spectra of the complexes reflect essentially absorption of the ligands for the fact that no obvious change of wavelength and band shape is found between the spectra of the complexes and that of the ligands except slight red shift. The IR absorption spectra indicate that salicylic acid is coordinated to the rare earth ions and chemical bonds are formed between rare earth ions and nitrogen atoms of o-phenanthroline. The fluorescence spectra of the complexes indicate that the fluorescence emission intensity of europium ion was enhanced by the addition of Y3+, which is referred to as cofluorescence. These facts show that not only the ligands but also the yttrium complex can transfer the absorbed energy to Eu3+ ion in the complexes. Formation of polynuclear complexes appears to be responsible for cofluorescence.

Europium↗

Influence of particle size on the quantitative determination of salicylic acid in a pharmaceutical ointment using FT-Raman spectroscopy.

A second order polynomial calibration model was developed and statistically validated for the direct and non-destructive quantitative analysis - without sample preparation - of the active pharmaceutical ingredient (API) salicylic acid in a pharmaceutical ointment using FT-Raman spectroscopy. The calibration curve was modeled by plotting the peak intensity of the vector normalized spectral band between 757 and 784cm(-1) against the known salicylic acid concentrations in standards. At this band, no spectral interferences from the ointment vehiculum (white vaseline) are observed. For the validation of the polynomial model, its fit and its predictive properties were evaluated. The validated model was used for the quantification of 25 ointments, compounded by different retail pharmacists. The same standards and samples were used, both for development and validation of a regression model and for quantitative determination by HPLC - with sample preparation - as described for the related substances of salicylic acid in the Ph. Eur. IV. The quantification results obtained by the FT-Raman method corresponded with the HPLC results (p=0.22), provided that the particle size of salicylic acid in the standards is the same as in the analyzed samples. The non-destructive FT-Raman method is a reliable alternative for the destructive HPLC method, as it is faster and does not require sample pre-treatment procedures.

Calibration↗

Structural basis for substrate recognition in the salicylic acid carboxyl methyltransferase family.

Recently, a novel family of methyltransferases was identified in plants. Some members of this newly discovered and recently characterized methyltransferase family catalyze the formation of small-molecule methyl esters using S-adenosyl-L-Met (SAM) as a methyl donor and carboxylic acid-bearing substrates as methyl acceptors. These enzymes include SAMT (SAM:salicylic acid carboxyl methyltransferase), BAMT (SAM:benzoic acid carboxyl methyltransferase), and JMT (SAM:jasmonic acid carboxyl methyltransferase). Moreover, other members of this family of plant methyltransferases have been found to catalyze the N-methylation of caffeine precursors. The 3.0-A crystal structure of Clarkia breweri SAMT in complex with the substrate salicylic acid and the demethylated product S-adenosyl-L-homocysteine reveals a protein structure that possesses a helical active site capping domain and a unique dimerization interface. In addition, the chemical determinants responsible for the selection of salicylic acid demonstrate the structural basis for facile variations of substrate selectivity among functionally characterized plant carboxyl-directed and nitrogen-directed methyltransferases and a growing set of related proteins that have yet to be examined biochemically. Using the three-dimensional structure of SAMT as a guide, we examined the substrate specificity of SAMT by site-directed mutagenesis and activity assays against 12 carboxyl-containing small molecules. Moreover, the utility of structural information for the functional characterization of this large family of plant methyltransferases was demonstrated by the discovery of an Arabidopsis methyltransferase that is specific for the carboxyl-bearing phytohormone indole-3-acetic acid.

Amino Acid Sequence↗

[Effects of methyl jasmonate and salicylic acid on phenylethanoid glycosides synthesis in suspension cultures of Cistanche deserticola].

The present study investigated the influence of the methyl jasmonate and salicylic acid elicitors on the formation of phenylethanoid glycosides (PeG) in the suspension cultures of Cistanche deserticola. The results showed that methyl jasmonate and salicylic acid enhanced greatly the accumulation of PeG and echinacoside (Echin), but their optimum elicitation dosage and addition time were different. The yields of PeG and Echin were significantly increased in the presence of 5 micromol/L methyl jasmonate on day 14 (up to 2.59-fold and 3.82-fold, respectively), whereas treated with 50 micromol/L salicylic acid on day 28, the maximum content of them were, respectively, 2.71 and 3.16-fold higher than the untreated cell cultures.

Acetates↗

Effect of castration on acetyl salicylic acid metabolism in rabbits.

OBJECTIVES: The biotransformation of acetyl salicylic acid (ASA) differs within species, and gender differences have been documented and attributed to the effect of sex hormones. Castration remains a standard therapy for men with advanced prostate cancer. We studied the effect of castration on the metabolism of ASA in rabbits to find out whether the metabolism of ASA is adversely affected after castration. METHODS: ASA in doses of 12.5, 25, and 50 mg/kg body weight was given intravenously to male and female prepubertal and adult rabbits, castrated adult male rabbits, and castrated male rabbits given testosterone (3 animals per group). Blood samples were collected at 0, 10, 30, 60, 120, and 180 minutes. The high-performance liquid chromatography method was used for the quantitation of salicylic acid (SA) in serum. The percentage of SA not metabolized was determined by comparing the serum level at 10 and 180 minutes for each group. RESULTS: At a dose of 50 mg/kg in the adult rabbits, the mean +/- SD of SA in serum at 10 and 180 minutes was 146.54 +/- 29.54 microg/mL and 19.12 +/- 5.93 microg/mL for males, 158.25 +/- 6.70 microg/mL and 33.24 +/- 2.78 microg/mL for females, 229.72 +/- 47.85 microg/mL and 44.33 +/- 5.64 microg/mL for castrated male rabbits, and 170.88 +/- 12.03 microg/mL and 68.1 +/- 37.54 microg/mL for castrated male rabbits given testosterone, respectively. Also, at 180 minutes, the percentage of SA not metabolized in adult male rabbits was 12.82% +/- 1.65% compared with 21.04% +/- 2.14% (P <0.01) in adult females, 19.53% +/- 1.73% (P <0.01) in castrated adult male rabbits, and 38.95% +/- 19.48% (P <0.001) in castrated male rabbits given testosterone. At all doses of ASA, the serum SA concentration in male and female prepubertal rabbits was not significantly different for each time point. CONCLUSIONS: These results indicate that male rabbits are able to metabolize ASA faster than are females. After castration, this ability is significantly decreased. If these experimental results are confirmed in humans, men who are undergoing hormonal manipulation for advanced prostate cancer and who require high-dose ASA, such as in the treatment of stroke or rheumatoid arthritis or as an antioxidant, may need lower doses to reduce the possible toxic effects of ASA.

Androgen Antagonists↗

Salicylic acid attenuates virulence in endovascular infections by targeting global regulatory pathways in Staphylococcus aureus.

Aspirin has been previously shown to reduce the in vivo virulence of Staphylococcus aureus in experimental endocarditis, through antiplatelet and antimicrobial mechanisms. In the present study, salicylic acid, the major in vivo metabolite of aspirin, mitigated two important virulence phenotypes in both clinical and laboratory S. aureus strains: alpha-hemolysin secretion and fibronectin binding in vitro. In addition, salicylic acid reduced the expression of the alpha-hemolysin gene promoter, hla, and the fibronectin gene promoter, fnbA. Transcriptional analysis, fluorometry, and flow cytometry revealed evidence of salicylic acid-mediated activation of the stress-response gene sigB. Expression of the sigB-repressible global regulon sarA and the global regulon agr were also mitigated by salicylic acid, corresponding to the reduced expression of the hla and fnbA genes in vitro. Studies in experimental endocarditis confirmed the key roles of both sarA and sigB in mediating the antistaphylococcal effects of salicylic acid in vivo. Therefore, aspirin has the potential to be an adjuvant therapeutic agent against endovascular infections that result from S. aureus, by downmodulating key staphylococcal global regulons and structural genes in vivo, thus abrogating relevant virulence phenotypes.

Animals↗

The use of 13C solid state NMR to elucidate physico-chemical association in Eudragit RS100 microencapsulated acyl esters of salicylic acid.

A series of homogeneous Eudragit RS100 matrix microspheres containing molecularly dispersed acylated esterified homologues of salicylic acid, (acetylsalicylic acid, valerylsalicylic acid, or caprylsalicylic acid) were prepared in order to investigate the effect of encapsulation on solid-state orientation of the encapsulated molecule. Electrostatic association of the drug with the charged quaternary residues in the polymer may be responsible for the previously observed stability of acetylsalicylic acid (ASA) in aqueous swollen ASA-loaded Eudragit RS100 microspheres. Evaluation of the 13C nuclear magnetic resonance spectra for evidence of structural association of the incorporated probe molecules indicated that alteration of the microenvironment of the incorporated solutes had occurred. For instance, increasing the aliphatic character of the acyl side chain resulted in an increase in the upfield shift of the acyl bearing aromatic ring carbon, (C2), in the incorporated probe molecule as compared to the unincorporated probe molecule. Similarly, a downfield perturbation in the chemical shift of the free acid bearing aromatic ring carbon, (C1), was also observed. This microenvironment electrostatic shielding in the proximity of the ester carbonyl is attributed to an increase in the association of the probe molecule with the polymer subunits. Thereby, it is postulated that the matrix incorporated probe molecule is essentially shielded from hydrolytic attack until it is liberated into the external aqueous environment.

Acrylic Resins↗

An evaluation of the efficacy of topical application of salicylic acid for the treatment of familial cylindromatosis.

BACKGROUND: Familial cylindromatosis is a rare genetic disorder, giving rise to neoplasms of the skin appendages. We have recently shown that loss of the cylindromatosis tumour suppressor gene leads to activation of NF-kappaB, a transcription factor having antiapoptotic activity. This provides a possible explanation for the deregulated growth of cylindromas. In cell-based assays, salicylate can prevent NF-kappaB activation caused by loss of the cylindromatosis gene, suggesting that salicylic acid application might be a potential treatment for cylindromatosis. OBJECTIVES: To assess the effectiveness of topical application of salicylic acid on familial cylindromas. METHODS: Cylindromas in five patients from four different cylindromatosis families were treated with twice daily and then once daily topical salicylic acid. Clinical response was determined by serial tumour measurements. RESULTS: In total 17 cylindromas in five patients were studied: 12 target lesions and five control lesions. The median size of the cylindromas was 1.0 cm (range, 0.6-2.8 cm). Two of the 12 cylindromas showed a complete remission. Another eight lesions showed some response, but not sufficient to qualify as partial remission. The control lesions remained stable or increased in size. CONCLUSIONS: Salicylic acid is a well-tolerated and potential new treatment for cylindromatosis.

Administration, Topical↗