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PubMed2005

Assay of free ferulic acid and total ferulic acid for quality assessment of Angelica sinensis.

Activity of Chinese Danggui (DG), the processed root of Angelica sinensis (Oliv.) Diels, is linked to the ferulic acid content but the stability of ferulic acid during extraction for medicinal use is not known. The stabilities of ferulic acid and coniferyl ferulate were evaluated in the extracts of DG using a variety of extraction solvents. These included various combinations and proportions of methanol, water, formic acid, 1 M aqueous hydrochloric acid and 2% sodium hydrogen carbonate (NaHCO3) in water. Coniferyl ferulate was found liable to hydrolyze into ferulic acid in neutral, strongly acidic and basic solvents, where heat and water could facilitate this hydrolysis. However, the hydrolysis was relatively resisted in weakly organic acid. Based on the stability evaluation, two new terms, namely: free ferulic acid and total ferulic acid, were suggested and defined. Free ferulic acid refers to the natural content of ferulic acid in herbs. Total ferulic acid means the sum of free ferulic acid plus the amount of related hydrolyzed components. Meanwhile, the high-performance liquid chromatographic (HPLC) method was developed to assay free ferulic acid and total ferulic acid in DG using methanol-formic acid (95:5) and methanol-2% NaHCO3 in water (95:5) as extraction solvents, respectively. Ten DG samples were investigated on their contents of free and total ferulic acid. The results indicated that the amount variety of free ferulic acid was larger than that of their counterparts, and the ratio of total ferulic acid to free ferulic acid was 4.07 +/- 2.73 (mean +/- SD, n = 10). The chemical assay of DG using total ferulic acid content would be a better choice to assess the herbal quality and was recommended.

Angelica sinensis↗
PubMed2000

FT-IR spectroscopy of supersaturated aqueous solutions of magnesium borate.

FT-IR spectra of supersaturated aqueous solution of magnesium borate, its acidized solutions with azeotropic hydrochloric acid, and its diluted solutions with water have been recorded. The FT-IR spectra of borate in solution are obtained by difference, subtracting the FT-IR spectrum of water from that of the magnesium borate supersaturated aqueous solution. All of the results showed that various polyborate anions in the supersaturated aqueous solutions exist. The bands of symmetric pulse vibration of the corresponding polyborate anions were indicated and some assignments were tentatively given.

Borates↗
PubMed2003

Determination of total folate in plant material by chemical conversion into para-aminobenzoic acid followed by high performance liquid chromatography combined with on-line postcolumn derivatization and fluorescence detection.

A procedure involving chemical conversion of all forms of folate present in plant material into para-aminobenzoic acid (PABA) and a liquid chromatographic-fluorimetric determination with on-line postcolumn derivatization is reported. All folates are cleaved with liberation of PABA by hydrogen peroxide followed by acid hydrolysis using concentrated hydrochloric acid (37%) at 110 degrees C for 6 h. The reaction yield for individual folates conversion to PABA ranged from 44.4 to 97.3%. PABA could be determined sensitively by on-line postcolumn derivatization with fluorescamine, the detection limit for PABA being 3.02 nM. On the basis of this principle, a method for the determination of total folate in plant material, including a purification step on an affinity column, is presented, which offers a sufficient sensitivity and selectivity for routine analysis of total folate in natural samples. The total folate contents of tomatoes, carrots, white cabbage, and spinach were determined, and the results were quite comparable to the data reported. The recovery of PABA and the comparison of total folate analysis in spinach on different occasions (over 6 months) are also reported. The method is reliable, universal for all folates, including polyglutamate and monoglutamate forms, and eliminates the need for a deconjugation step and multiple conversion reactions.

4-Aminobenzoic Acid↗
PubMed2004

On the adsorption kinetics of surface-chemically pure n-dodecanoic acid at the air/water interface.

The dynamic surface tension data for n-dodecanoic acid in 0.005 M hydrochloric acid, for as-received as well as for surface-chemically pure solutions, show the presence of a prolonged induction period, clearly indicating that the adsorption of this nonionic surfactant is not simply diffusion-controlled. A kinetic model for the reversible formation of monolayer islands, long known in the field of electrochemistry, is shown to also apply to the adsorption of n-dodecanoic acid at the air/water interface. The rate constant increases linearly with increasing bulk concentration, while the induction time decreases exponentially. The phenomenon of nucleation at the air/water interface is consistent with the direct experimental observation of the formation of solid-like patches as the interfacial region is drastically compressed.

Adsorption↗
PubMed2002

An investigation of the chemical stability of arsenosugars in simulated gastric juice and acidic environments using IC-ICP-MS and IC-ESI-MS/MS.

A more quantitative extraction of arsenic-containing compounds from seafood matrices is essential in developing better dietary exposure estimates. More quantitative extraction often implies a more chemically aggressive set of extraction conditions. However, these conditions may result in undesirable chemical changes in the native arsenicals which may further complicate the toxicological risk assessment. This balance between quantitative extraction and species-specific integrity may be best addressed by using simulated gastric juice as an extraction solvent to mimic 'bioavailability'. This, conceptually, should extract the bioavailable fraction and induce any chemical changes that would occur because of ingestion. The most chemically labile species associated with seafood are thought to be the arsenosugars and for this reason their chemical stability is investigated in this study. Four arsenosugars (3-[5'-deoxy-5'-(dimethylarsinoyl)-beta-ribofuranosyloxy]-2-hydroxypropylene glycol, As(328); 3-[5'-deoxy-5'-(dimethylarsinoyl)-beta-ribofuranosyloxy]-2-hydroxypropanesulfonic acid, As(392); 3-[5'-deoxy-5'-(dimethylarsinoyl)-beta-ribofuranosyloxyl-2-hydroxypropyl hydrogen sulfate, As(408); and 3-[5'-deoxy-5'-(dimethylarsinoyl)-beta-ribofuranosyloxy]-2-hydroxypropyl-2,3-hydroxypropyl phosphate, As(482)) were isolated from seaweed extracts and subjected to simulated gastric juice and acidic conditions which mimic the stomach's pH of 1.1. Three acid solutions were used to test the chemical stability of the arsenosugars: simulated gastric juice, 78 mM nitric acid and 78 mM hydrochloric acid. The composition of the solutions was monitored over time (up to 48 h) using IC-ICP-MS for detection. The arsenosugars were found to degrade at the rate of 1.4% per h at 38 degrees C and 12.2% per h at 60 degrees C. The plots of percent conversion versus time were found to be independent of the starting arsenosugar and all had r2 values of greater than 0.97. A single common degradation product was observed in all the stability studies. A mass balance between the starting arsenosugar (As(392), As(408) and As(482)) and the degradation product was conducted with each set of experiments. This mass balance indicated that the degradation process did not produce any unchromatographable species. This degradation product was tentatively identified as As(254) as determined by ESI-MS/MS spectral data. An acid hydrolysis mechanism was proposed for the formation of As(254) from each of the native arsenosugars by hydrolysis at the C-1 carbon on the ribose ring.

Animals↗
PubMed2003

Characterization of a 35-kDa carbohydrate larval antigen (CarLA) from Trichostrongylus colubriformis; a potential target for host immunity.

In an accompanying paper we show that antibodies in intestinal mucus that recognize a 35-kDa antigen from the surface of the L3 stage of the sheep intestinal nematode parasite, Trichostrongylus colubriformis, are strongly associated with immune rejection of L3 in a truncated infection model of immunity in sheep. Monoclonal antibody PAB-1 was used to immunopurify this antigen from T. colubriformis L3. The antigen is resistant to digestion with a range of proteases including proteinase K and does not stain on gels or blots treated with protein-detecting reagents but does stain with carbohydrate-detecting reagents. The antigen is also resistant to degradation by the action of lipases and is not soluble in organic solvents, suggesting that lipid components are not present or not accessible. Treatment with glycosidases does not affect the antigen, indicating either that sialic acid and N-linked or O-linked sugars are not present or that they are not accessible to enzyme attack. The antigen is not destroyed by harsh alkaline degradation with up to 8 m NaOH with or without borohydride reducing agent, or by extensive hydrazinolysis. Strong acid hydrolysis with trifluoroacetic acid or boiling in hydrochloric acid for 20 min does destroy the antigen. The antigen migrates as a poorly defined high molecular weight complex on native electrophoresis gels, but is detected as a major band at 35 kDa on SDS PAGE either by carbohydrate staining or by immunoblotting with antibody from immune sheep intestinal mucus and with mAb PAB-1. Proteinase K digestion and alkaline degradation of extracts from L3 of 10 other parasitic nematode species revealed that L3 of each species contained a carbohydrate staining molecule which can be detected by mAb PAB-1 and by mucus antibody from immune sheep. Because antibodies in intestinal mucus are directed against these antigens and may be responsible for protective immunity, carbohydrate larval antigens (CarLA) could represent a new family of molecules with potential as targets for stimulating host immunity.

Animals↗
PubMed2000

Neuromodulation reduces urinary frequency in rats with hydrochloric acid-induced cystitis.

OBJECTIVE: To evaluate the effect of sacral neuromodulation on interstitial cystitis (IC) and determine the underlying mechanism of neuromodulation in the treatment of IC. Materials and methods Twenty Sprague-Dawley rats (body weight 220-250 g) were randomly divided into four equal groups; normal controls, a sham treatment (IC induced by 0.4 mol/L HCl, + saline), a second sham treatment (HCl-induced IC + acetic acid) and a stimulated group (HCl-induced IC + acetic acid, with electrical stimulation). In the last group bilateral electrodes were implanted into the S1 dorsal foramina and electrical stimulation applied for 8 h/day for 3 weeks. Acetic acid was instilled into the bladder to induce c-fos expression. After 3 weeks the rats were perfused with 4% paraformaldehyde, spinal segments dissected out and an immunocytochemical method used to stain the segments for fos protein encoded byc-fos. RESULTS: The mean (SEM) micturition frequency (voids/17 h) in the sham groups increased from 10.8 (2.7) to 23.4 (3.4) 3 weeks after the intravesical instillation of HCl. The micturition frequency in the stimulated group, at 16.2 (2.7), was significantly less than in the sham group (P = 0.04) after electrical stimulation for 3 weeks. There was no significant difference in the mean (SEM) number of fos-positive neurones in the L6 spinal cord segment between the stimulated and the sham + acetic acid group, at 43.6 (9.4) and 35.8 (7.8) cells/section, respectively (P = 0.32). CONCLUSIONS: In rats with HCl-induced cystitis, electrical stimulation reduced the micturition frequency, but not by inhibiting afferent c-fibre activity.

Animals↗
PubMed1992

Anti-inflammatory and analgesic effects of an aqueous extract of Harpagophytum procumbens.

The dried aqueous extract of Harpagophytum procumbens (Pedaliaceae) and its main iridoid glycoside, harpagoside, have been evaluated for anti-inflammatory and analgesic effects in mice and rats, in order to validate or invalidate the involvement of this compound in such properties. This extract exerted significant and dose-dependent anti-inflammatory and analgesic effects, from the dose 100 mg of dried secondary roots/kg, the first being obtained on an acute inflammatory process (carrageenan-induced edema test in rats) and the second being obtained against a chemical stimulus (writhing test in mice). Harpagoside does not appear to be involved in anti-inflammatory properties, since this iridoid glycoside did not protect against carrageenan inflammatory effects when it was used at 5 and 10 mg/kg; 5 mg corresponding to the quantity contained in 400 mg of dried secondary roots. The main iridoid glycoside of H. procumbens appears to be implicated in the peripheral analgesic properties of this species, but other compounds have to be involved, since the dose of 10 mg/kg exerted a significant protective effect. The absence of the activity of H. procumbens after an acid treatment (0.1 N hydrochloric acid), stomach, suggests the use of a suitable galenic preparation in order to protect the active principles from the action of the acid released in the stomach.

Analgesics↗
PubMed2000

Preparation, hydrolysis and intramolecular transesterification of 3'-deoxy-3'-thioinosine 3'-S-dimethylphosphorothiolate.

The hydrolytic reactions of the dimethyl ester of 3'-deoxy-3'-thioinosine 3'-S-phosphorothiolate have been followed over a wide aciditiy range by HPLC. At pH > 3, only hydroxide ion catalyzed isomerization to the 2'-dimethylphosphate takes place, whereas under more acidic conditions hydrolysis to the 2'-monomethylphosphate and 3'-S-monomethylphosphorothiolate competes. The latter is the only product accumulating in very acidic solutions (1 M hydrochloric acid). Mechanisms of the reactions are discussed.

Chromatography, High Pressure Liquid↗
PubMed1978

An electron microscopic study of the location of peptidoglycan in group A and C streptococcal cell walls.

The morphological appearance of deproteinized Group A and C streptococcal walls after treatment by different procedures extracting teichoic acids and polysaccharides (formamide, hydrochloric acid, nitrous acid, trichloroacetic acid, sulphuric acid, sodium hydroxide and sodium deoxycholate) was compared with the content of teichoic acids and polysaccharides remaining in the treated walls. All procedures extracted teichoic acids almost completely, but polysaccharides were extracted to various degrees. The ultrastructural appearance of walls after these extractions still exhibited the triple-layered wall profile; only a reduction of thickness of the wall and of electron density of the layers occurred. There was no direct correlation between the reduction of rhamnose content and thickness of walls. The ultrastructural localization of peptidoglycan in the streptococcal walls was explored by means of the indirect immunoferritin technique using anti-peptidoglycan antibodies isolated from anti-Group A-variant antisera. Ferritin particles were bound predominantly to filamentous structures which protruded from both surfaces of peptidoglycan fragments and isolated walls. Peptidoglycan was also detected on the filamentous protrusions of whole cocci. These results contradict models of the streptococcal wall in which peptidoglycan forms the innermost layer and support a mosaic structure in which peptidoglycan forms a network of the peptidoglycan-polysaccharide complex.

Antibodies, Bacterial↗
PubMed2002

Rapid determination of 226Ra and uranium isotopes in solid samples by fusion with lithium metaborate and alpha spectrometry.

A simple and rapid method has been developed to determine 226Ra in rocks, soils, and sediments. Samples are decomposed by fusion with lithium metaborate and the melt is dissolved in a solution containing sulfates and citric acid. During the dissolution, a fine suspension of mixed barium and radium sulfates is formed. The microcrystals are collected on a membrane filter (pore size 0.1 microm) and analysed in an alpha spectrometer. Application of a 133Ba tracer enables us to assess the loss of the analyte, which only rarely exceeds 10%. All analytical operations, beginning from sample decomposition to source preparation for alpha spectrometry, can be accomplished within 1 or 2 h. With uranium determination, the filtrate is spiked with a 232U tracer and passed through a column loaded with a Dowex AG (1 x 4) anion-exchange resin in the sulfate form. Interfering elements are eluted with dilute sulfuric acid followed by concentrated hydrochloric acid. Uranium is eluted with water, electrodeposited on silver discs, and analysed in the alpha spectrometer. The method was tested on reference soil and sediment materials and was found to be accurate within the estimated uncertainties.

Borates↗
PubMed1995

Skin irritation in man: a comparative bioengineering study using improved reflectance spectroscopy.

Variable types of skin irritation were induced in 8 human female volunteers, ranging from subclinical to visible erythema with slight oedema. Skin reactions were graded clinically and objectively using transepidermal water loss (TEWL), laser Doppler flowmetry (LDF) and improved reflectance spectroscopy. This last technique enables separation of in vivo erythemas into relatively deoxygenated (venous--deoxy hem) and oxygenated (arterial--oxy hem) haemoglobin components. Compared to uninvolved skin, an empty patch increased oxy hem by 197% +/- 121% (p < 0.05). Exposure to vehicles also changes skin biophysics. At sodium lauryl sulfate (SLS) and hydrochloric acid (HCl) exposed sites, a linear correlation between concentration and oxy hem, LDF and TEWL was found. These chemicals predominantly increased TEWL values. Nonanoic acid (NON) and imipramine (IMI) also raised oxy hem, LDF and TEWL values linearly at increasing concentrations. Although IMI 2.5% clinically was graded as a type ++ response, no significant increase in TEWL was found. The improved reflectance spectroscopic technique proved valid in skin irritation studies, with a higher sensitivity than laser Doppler flowmetry, and allowed irritant vascular reactions to be discriminated into arterial and venous components. Furthermore, our observations clearly demonstrate that clinically indistinguishable skin irritation reactions induce significantly different changes in barrier function (disruption) and vascular status.

Adult↗
PubMed1992

Acid adaptation promotes survival of Salmonella spp. in cheese.

Salmonella typhimurium was adapted to acid by exposure to hydrochloric acid at pH 5.8 for one to two doublings. Acid-adapted cells had increased resistance to inactivation by organic acids commonly present in cheese, including lactic, propionic, and acetic acids. Recovery of cells during the treatment with organic acids was increased 1,000-fold by inclusion of 0.1% sodium pyruvate in the recovery medium. Acid-adapted S. typhimurium cells survived better than nonadapted cells during a milk fermentation by a lactic acid culture. Acid-adapted cells also showed enhanced survival over a period of two months in cheddar, Swiss, and mozzarella cheeses kept at 5 degrees C. Acid adaptation was found in Salmonella spp., including Salmonella enteritidis, Salmonella choleraesuis subsp. choleraesuis serotype heidelberg, and Salmonella choleraesuis subsp. choleraesuis serotype javiana, associated with food poisoning. These observations support the theory that acid adaptation is an important survival mechanism enabling Salmonella spp. to persist in fermented dairy products and possibly other acidic food products.

Adaptation, Physiological↗
PubMed1988

Antropyloroduodenal activity during gastric emptying of liquid meals in humans.

The present study examines the possible roles of the pylorus and the proximal duodenum in the gastric emptying of two liquid meals in six healthy volunteers. Gastric emptying of a saline meal (150 mM) and an acid meal (120 mM hydrochloric acid) were measured by the double-sampling dye dilution technique while antroduodenal motility was monitored with a continuously perfused catheter system. Pyloric region pressures were measured with a Dent sleeve. The acid meal (t1/2 = 13.5 +/- 1.8 min) emptied significantly (P less than 0.01) slower than the saline meal (t1/2 = 3.5 +/- 0.7 min). This slowing in the emptying of the acid meal was associated with significant (P less than 0.05) increments in tonic pyloric activity and phasic contractions of the proximal duodenum. Thus the gastric emptying of liquid meals is a complex process involving all components of the gastroduodenal region.

Adult↗
PubMed1999

Isolation and characterization of acid- and bile-tolerant isolates from strains of Lactobacillus acidophilus.

Lactic acid bacteria have been reported to be useful as a health adjunct and are commonly added to food as the delivery mechanism. The literature contains many conflicting observations for their proposed benefits, and the mechanism of action is undefined. One source of variation is the large number of strains used without proper controls supplemented. Additionally, many of the organisms are not characterized for their acid shock response or the acid-tolerance response, which are known to vary among bacterial species. Our objective was to isolate acid-resistant and bile-resistant variants of Lactobacillus acidophilus and to determine the phenotypic changes. The acid- and bile-tolerant isolates were obtained using natural selection techniques after sequential exposure to hydrochloric acid (pH 3.5 to 7.0) and mixed bile salts. The acid- and bile-tolerant isolates retained their ability to grow at pH 3.5 with 0.3% bile after the selective pressure was removed and reapplied. Isolates varied from their parents for stability in freezing, lactose utilization, protease activity, aminopeptidase activity, plasmid profile, and cell-wall fatty acid profile. These data suggest that the isolated acid- and bile-tolerant isolates possess growth advantages over that of the parents under stress conditions and may be considered as candidates for probiotic strains after further characterization with animal models.

Aminopeptidases↗
PubMed1975

[Chemical burns of the stomach in children].

Under observation were seven children, aged from 1 year 4 months to 6 years, with isolated gastric burns. In 4 children the burn was produced by sulphuric acid, in 2 -- by hydrochloric acid, in 1 -- by an unknown poison. All these patients were operated upon, 6 children with decompensated stenoses within the terms from 30 to 48 days, 1 child with a subcompensated stenosis -- 3 months following the burn. Gastroenterostomy was performed in all of them: in 6 -- posterior, in 1 -- anterior with an accessory interintestinal stoma. All patients recovered and were discharged from the clinic 10--12 days following the operation. Late results were studied in 4 children during the period from 2 to 9 years postoperatively. All of them are feeling well.

Adolescent↗
PubMed2002

Heavy metals extraction from anaerobically digested sludge.

This paper reports on the chemical extraction efficiency in the removal of heavy metals from sludge from an activated-sludge system, which receives as influent both industrial and municipal wastewater. Utilizing a series of chemical extractants in a sequential order comprised the first phase of the research, called sequential chemical extraction (SCE). The work started with the well-known Tessier method followed by Veeken and by Sims and Kline SCE schemes. Afterwards, modified versions of Tessier and Veeken schemes were applied. The second phase, named chemical extraction using pH progressive changes, concerns an alternative to the extraction process. Four acids were tested: nitric, hydrochloric, oxalic and citric and the pH values as well as the time were varied. Some conclusions reveal that although modifying Tessier and Veeken schemes provides more consistent results, SCE is still an imperfect method regarding specificity and selectivity. Besides, it is not advisable to apply one SCE scheme developed for one specific situation to another one, once the accurateness of the method depends on several factors such as sort of material and chemicals, contact time, temperature, etc. The extraction efficiency increases using nitric or hydrochloric acids at low pH values, promoting high extraction efficiency level.

Bacteria, Anaerobic↗