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PubMedDate not supplied

Measurement of salicylsalicylic acid and salicylic acid in plasma by high pressure liquid chromatography.

Salicylsalicylic acid (SS) and salicylic acid (SA) both appear in plasma after the oral ingestion of the former. They can be estimated in the presence of each other after extraction into dichloromethane using high pressure liquid chromatography. SS is unstable in plasma, being converted to SA in vitro. Conversion can be prevented by using ethylene diaminetetraacetic (EDTA) as an anticoagulant and carrying out the extraction in the cold. An aliquot of the extract is dried and dissolved in methanol. Weak solutions of SS in methanol are unstable at room temperature. Methanolysis can be prevented by the addition of dilute hydrochloric acid. By adding phenylbutazone to the plasma as an internal standard, variations in extraction and sample application are nullified. Quality control is achieved by concurrent extraction of two different plasma standards containing SS and SA in known amounts. About 40 ng of SS and SA can be detected; reproducibility at 200 ng and above is better than 6.5 percent.

Chromatography, High Pressure Liquid↗
PubMed1995

Two inducers of plant defense responses, 2,6-dichloroisonicotinec acid and salicylic acid, inhibit catalase activity in tobacco.

2,6-Dichloroisonicotinic acid (INA) and salicylic acid (SA) are potent inducers of plant defense responses including the synthesis of pathogenesis-related (PR) proteins and the development of enhanced disease resistance. A soluble SA-binding protein has been purified from tobacco with an affinity and specificity of binding that suggest it is a SA receptor. Recently, this protein has been shown to be a catalase whose enzymatic activity is inhibited by SA binding. We have proposed that the resulting increase in intracellular levels of reactive oxygen species plays a role in the induction of defense responses such as PR protein gene expression. Here we report that INA, like SA, binds the SA-binding protein/catalase and inhibits its enzymatic activity. In fact, the dose-response curves for inhibition of catalase by these two compounds are similar. Furthermore, the ability of both INA analogues and SA derivatives to bind and inhibit tobacco catalase correlates with their biological activity to induce PR-1 gene expression and enhance resistance to tobacco mosaic virus. Comparison of the structures of INA, SA, and their analogues reveals several common features that appear to be important for biological activity. Thus, these results not only suggest that INA and SA share the same mechanism of action that involves binding and inhibition of catalase but also further indicate an important role for reactive oxygen species in the induction of certain plant defense responses. This is supported by the demonstration that INA-mediated PR-1 gene activation is suppressed by antioxidants.

Journal Article↗
PubMed2001

Induction of plant gp91 phox homolog by fungal cell wall, arachidonic acid, and salicylic acid in potato.

The oxidative burst has been suggested to be a primary event responsible for triggering the cascade of defense responses in various plant species against infection with avirulent pathogens or pathogen-derived elicitors. The molecular mechanisms of rapid production of active oxygen species (AOS), however, are not well known. We isolated homologs of gp91 phox, a plasma membrane protein of the neutrophil NADPH oxidase, from a potato cDNA library. Molecular cloning of the cDNA showed that there are two isogenes, designated StrbohA and StrbohB, respectively. The RNA gel blot analyses showed that StrbohA was constitutively expressed at a low level, whereas StrbohB was induced by hyphal wall components (HWC elicitor) from Phytophthora infestans in potato tubers. Treatment of potato tubers with HWC elicitor caused a rapid but weak transient accumulation of H2O2 (phase I), followed by a massive oxidative burst 6 to 9 h after treatment (phase II). Diphenylene iodonium (DPI), an inhibitor of the neutrophil NADPH oxidase, blocked both bursts, whereas pretreatment of the protein synthesis inhibitor cycloheximide with the tuber abolished only the second burst. These results suggest that the expression of StrbohA and StrbohB contributes to phase I and II bursts, respectively. The same is true for arachidonic acid, a lipid component of P. infestans-stimulated biphasic oxidative burst, whereas an endogenous signaling molecule, salicylic acid, only induced a weak phase II burst. Both molecules induced the StrbohB expression, which is in agreement with the second burst. To characterize the signal transduction pathway leading to the oxidative burst, we examined the role of protein phosphorylation in HWC-stimulated StrbohB gene expression. K252a and staurosporine, two protein kinase inhibitors, blocked the transcript accumulation. Two inhibitors of extracellular Ca2+ movement, however, did not abolish the transcript accumulation of StrbohB, suggesting that certain calcium-independent protein kinases are involved in the process of StrbohB gene expression. Additionally, we examined a causal relationship between the oxidative burst and expression of defense genes induced by the HWC elicitor. The transcript accumulation of genes related to sesquiterpenoid phytoalexin synthesis (lubimin and rishitin) and phenylpropanoid pathway was inhibited slightly by the DPI treatment, suggesting that the oxidative burst is not essential to activate these genes. Interestingly, the concomitant presence of DPI with the elicitor resulted in an increase in lubimin accumulation and a decrease in rishitin accumulation. Because it is known that lubimin is metabolized into rishitin via oxylubimin, we propose that AOS mediates the synthesis of rishitin from lubimin.

Amino Acid Sequence↗
PubMed1982

Bioavailability of acetylsalicylic acid and salicylic acid from rapid-and slow-release formulations, and in combination with dipyridamol.

Acetylsalicylic acid (ASA) is a strong, irreversible inhibitor of platelet aggregation, but loses this activity following first-pass deacetylation to salicylic acid (SA). In order to compare the bioavailability of unchanged ASA from rapid- and slow-release formulations, the single-dose concentration profiles of ASA and SA were studied in healthy volunteers following intake of two different rapid-release (conventional and effervescent tablets) and three different slow-release (microencapsulated ASA in tablets and in capsules, and enteric-coated tablets) formulations of ASA, and of one slow-release formulation of sodium salicylate. Since anti-platelet therapy with ASA is often combined with dipyridamol, the influence of this drug was also examined. The concentrations of ASA and SA were measured by high-pressure liquid chromatography. While the bioavailability of SA from the 5 ASA formulations was essentially equal and similar to that of the salicylate formulation, the bioavailability and peak concentrations of ASA appeared to be the much greater after rapid-release than after slow-release formulations. Indeed, ASA was only rarely detected in systemic blood following intake of slow-release ASA. Co-administered dipyridamol did not significantly influence the kinetics of ASA or SA. It appears that rapid-release formulations of ASA should be prefered in anti-platelet therapy, either alone or in combination with dipyridamol.

Adult↗
PubMed2006

'Keratolytic' properties of benzoyl peroxide and retinoic acid resemble salicylic acid in man.

OBJECTIVES: Retinoic acid (RA) and benzoyl peroxide (BP) were studied, comparing their keratolytic efficacy and water barrier disruption to that of salicylic acid (SA), a well-established keratolytic, under similar conditions. PATIENTS/METHODS: Six volunteers were included in this blinded study. Eleven randomized test sites were marked on the volar forearms, containing sites for untreated skin at time zero, unoccluded, occlusion, and vehicle controls for 3 and 6 h, and each of BP, RA, and SA solutions for 3 and 6 h. At each time point, occlusion at 5 of the test sites was removed, and chromameter measurements were performed over 30 min. Each site then underwent 25 stratum corneum (SC) tape strippings. At 1, 5, and 30 min after the last stripping at each site, TEWL measurements were performed. Quantitative protein analysis of the SC from the tapes was then performed. RESULTS AND CONCLUSION: after 3 h, bp was significantly more effective in disrupting sc cohesion than sa and ra, indicating bp is a moderate keratolytic agent in addition to its antimicrobial properties. After 6 h, all three agents were similarly effective in keratolysis. Barrier disruption, as measured by TEWL, paralleled depth of SC removal. SA tended to exhibit the greatest keratolytic efficacy superficially, hence its clinical effectiveness in superficial conditions such as comedonal acne, whereas BP was more effective at deeper levels, complimenting its antimicrobial effects and enabling it to treat deeper, more inflammatory lesions. None of the agents significantly affected skin erythema. These techniques provide a robust and rapid assay for in vivo keratolytic demonstration.

Adult↗
PubMed2003

The gene encoding glutathione-dependent formaldehyde dehydrogenase/GSNO reductase is responsive to wounding, jasmonic acid and salicylic acid.

It has recently been discovered that glutathione-dependent formaldehyde dehydrogenase (FALDH) exhibits a strong S-nitrosoglutathione reductase activity. Plants use NO and S-nitrosothiols as signaling molecules to activate defense mechanisms. Therefore, it is interesting to investigate the regulation of FALDH by mechanical wounding and plant hormones involved in signal transduction. Our results show that the gene encoding FALDH in Arabidopsis (ADH2) is down-regulated by wounding and activated by salicylic acid (SA). In tobacco, FALDH levels and enzymatic activity decreased after jasmonate treatment, and increased in response to SA. This is the first time that regulation of FALDH in response to signals associated with plant defense has been demonstrated.

Aldehyde Oxidoreductases↗
PubMed1993

Biotransformation of para-aminobenzoic acid and salicylic acid by PMN.

Para-aminobenzoic acid (PABA) is an essential cofactor for the production of folic acid in bacteria and has mild anti-inflammatory activity. We have recently reported that salicylic acid and benzoic acid are oxidized by stimulated granulocytes Polymorphonuclear Neutrophils (PMN). The oxidation of salicylate appears mediated by a potent oxygen metabolite generated during the respiratory burst which is dependent primarily on superoxide (O2-) for its production. These background studies with the salicylate group of drugs suggested that PABA might be similarly metabolized by PMN. In these studies, we demonstrate that PABA is metabolized by stimulated PMN. However, in contrast to the biochemical mechanism involved in the metabolism of salicylate, our scavenger studies indicate that PABA is metabolized primarily by the myeloperoxidase pathway. Our results may explain the mild anti-inflammatory actions of the drug and suggest that the degradation of PABA by PMN at an inflammatory site may limit the availability of PABA for bacterial growth.

4-Aminobenzoic Acid↗
PubMed1990

Penetration of salicylic acid and salicylate into the multilayer membrane system and into the human horny layer.

Using a multilayer membrane system and human horny layer the difference in the penetration of salicylic acid (SA) and its sodium (Na-S) and choline (Ch-S) salts from topical formulations was studied. It was found Na-S and Ch-S were markedly accumulated in the first membrane of the three layer membrane system used. In contrast, a rapid penetration into all three membranes was observed when SA was used. Similar penetration profiles were obtained in human horny layer. Hence, the use of the salts of SA appears to be more suitable for the application as keratolytic.

Epidermis↗
PubMed2006

Comparison of the effects of pulsed dye laser, pulsed dye laser + salicylic acid, and clobetasole propionate + salicylic acid on psoriatic plaques.

BACKGROUND: Studies show that pulsed dye laser (PDL) has some clinical benefits on psoriasis with a low clearance rate. In addition, it has been suggested that applying keratolytics before treatment might be helpful in PDL therapy. Topical corticosteroids remain the most commonly prescribed agents for psoriasis. OBJECTIVE: This study was designed to compare the efficacy of the PDL treatment with that of PDL treatment after salicylic acid on psoriatic plaques. The other goal of this study was to compare the efficacy of the PDL treatment with that of clobetasol propionate treatment. METHODS: Twenty-two patients with chronic, stable psoriatic plaques that involved less than 20% of their body were included in the study. Three similar-appearing psoriasis plaques in these patients were selected. Whereas the first plaque received only PDL, the second plaque received PDL after salicylic acid, and the third plaque received clobetasol propionate ointment and salicylic acid. Evaluation of the study plaques was carried out by the modified Psoriasis Area and Severity Index (mPASI) score and by measuring the area of the plaques. RESULTS: Of the 21 patients, 19 completed the study. Although the decrease in mPASI scores was determined to be maximum for clobetasol propionate + salicylic acid-treated plaques and minimum for only PDL-treated plaques, the decrease was statistically significant in all groups when compared with baseline (p < .003). At the 3- and 6-week evaluations, there was a statistically significant difference between clobetasol propionate + salicylic acid-treated plaques and the two PDL-treated plaques (p < .003); however, the difference observed at the 9-, 12-, and 15-week evaluations was statistically significant only between clobetasol propionate + salicylic acid-treated plaques and PDL-treated plaques (p < .003). When the baseline and 15-week evaluations were compared, there was no statistically significant increase in the mean lesion areas of clobetasol propionate + salicylic acid-treated psoriatic plaques (p > .003), but there was a statistically significant increase in the mean lesion areas of two PDL-treated psoriatic plaques (p < .003). CONCLUSION: The results of this study showed that the effect of PDL could be increased when salicylic acid was added to treatment, although there was no statistically significant difference between both treatment protocols. However, clobetasol propionate + salicylic acid treatment is more effective than both PDL and PDL + salicylic acid treatment.

Adult↗
PubMed2003

Effect of plant growth-promoting Rhizobacteria and culture filtrate of Sclerotium rolfsii on phenolic and salicylic acid contents in chickpea (Cicer arietinum).

Two plant growth-promoting rhizobacteria (PGPR), viz., Pseudomonas fluorescens strain Pf4 and P. aeruginosa strain Pag, protected chickpea ( Cicer arietinum) plants from Sclerotium rolfsii infection when applied singly or in combination as seed treatment. Pag gave the best protection to the seedlings, applied either singly (mortality 16%) or in combination with Pf4 (mortality 17%) compared with 44% and 24% mortality in control and Pf4 treatment, respectively. The two PGPR strains induced the synthesis of specific phenolic acids, salicylic acid (SA), as well as total phenolics at different growth stages of chickpea seedlings with varied amount. The maximum amount of total phenolics was recorded in all the aerial parts of 4-week-old plants. Gallic, ferulic, chlorogenic, and cinnamic acids were the major phenolic acids detected in high-performance liquid chromatography (HPLC) analysis. Induction of such phenolic acids in the seedlings was observed up to 6 weeks in comparison with control. Salicylic acid (SA) was induced frequently during the first 3 weeks of growth only. Between the two strains, Pag was more effective in inducing phenolic acid synthesis applied either singly or in combination with strain Pf4 during the entire 6 weeks of growth of chickpea. In the presence of a culture filtrate of S. rolfsii, the two Pseudomonas strains induced more phenolic acids in treated than in non-treated and control plants. The occurrence of salicylic acid was frequent in the first 24 h, but infrequent at 48 and 96 h. Foliar spray of Pseudomonas strains also enhanced the phenolic acid content as well as total phenolics within 24 h of application. Gallic, chlorogenic, and cinnamic acids were consistently discerned in the treated leaves, whereas SA was absent even up to 96 h of application. Resistance in chickpea plants by Pseudomonas strains through induction of phenolic compounds as well as induced systemic resistance via SA-dependent pathway was evident.

Antibiosis↗
PubMed1991

Decrease of gastrointestinal mucosal damage by salicyluric acid compared with salicylic acid in rabbits.

The gastrointestinal mucosal damage following the oral administration of salicylic acid or salicyluric acid was examined in rabbits using a scanning electron microscope. Six and 24 h after treatment with salicylic acid, morphological changes of gastric mucosa were recognized. In rabbits treated with salicyluric acid, however, severe damage in the gastric mucosa was not found after 24 h compared with the treatment with salicylic acid. Following the treatment with salicylic acid, some mucosal damage in the duodenum, jejunum and ileum was observed after 24 h. The surface character of the duodenal, jejunal, ileal, caecal and colonic mucosa were almost identical compared with the control following the treatment with salicyluric acid. It was reported that salicyluric acid is metabolized to salicylic acid by the intestinal microorganisms. From these results, it was suggested that prodrugs utilizing the metabolism of salicyluric acid to salicylic acid by intestinal microorganisms may be useful in reducing gastrointestinal mucosal damage.

Administration, Oral↗