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PubMedDate not supplied

Cytochrome P-450 metabolic-intermediate complex formation from p-aminobenzoic acid esters and other arylamines.

Metabolism of a series of p-aminobenzoic acid esters by rat liver microsomal fractions resulted in the formation of cytochrome P-450 metabolic - intermediate complexes. With conditions that allowed complex formation to proceed to completion, about 20% of control rat cytochrome P-450 was sequestered as a complex. Phenobarbital, but not beta-naphthoflavone induced additional cytochrome P-450, which with specific esters could be complexed to about 60%. For other esters, the induced cytochrome maximally complexed to about 20%, as was seen in uninduced rats. The two groups of p-aminobenzoic acid esters could not be readily delineated by lipid/water partition coefficients or steric factors.

4-Aminobenzoic Acid↗
PubMed1988

[The effect of aminobenzoic acid derivatives on the ion current of myelinated neurons. 2. Inactivation of sodium permeability].

Effects of Aminobenzoic Acid Derivatives on the Ionic Currents in Myelinated Nerve/2nd Communication: Sodium inactivation. Derivatives of aminobenzoic acid similar to metacaine were modified and their effects on the sodium inactivation and on the sodium permeability constant, PNa, of single potential clamped myelinated nerve fibres were tested. Comparing the observed shift of the inactivation curves and the reduction of PNa with the octanol/water partition coefficients of the drugs tested, a minimum lipid solubility seems to be necessary for the substances being efficacious. It is assumed that the uncharged aminobenzoic acids reduce PNa by disturbing the lipid matrix in an unspecific manner. The observed shift of the inactivation curves is explained in terms of the fixed charges at the inside of the membrane being moved apart by the uncharged compounds thus lowering the effective membrane potential. Moreover, no indications for a receptor-mediated mechanism were found.

Aminobenzoates↗
PubMed2006

Determination of amino acids in tobacco samples by capillary electrophoresis/indirect absorbance detection with isolation of the electrolysis compartment and p-Aminobenzoic acid as a background electrolyte.

A fast, convenient and sensitive method of capillary zone electrophoresis (CZE) and indirect UV detection was proposed for the determination of 16 amino acids. p-Aminobenzoic acid (PAB) was selected as a background electrolyte (BGE). An isolated cell included a BGE buffer part and an electrode buffer one, which were jointed with a glass frit. The isolated cell can prevent PAB from the electrode reaction and improve the stability of the detection baseline. The separation conditions of amino acids were investigated, such as different BGEs, BGE concentration, buffer pH and electroosmotic flow (EOF) modifiers. Under the selected separation conditions, 14 amino acid peaks could be separated in 12 min. The detection limits of the amino acids were in the range of 1.7 - 4.5 micromol/L. The isolated cell is suitable for reagents reacting on the electrodes in capillary electrophoresis. The proposed method has been successfully applied to the determination of the amino acids in tobacco samples.

4-Aminobenzoic Acid↗
PubMed2002

Determination of para-aminobenzoic acid, a degradation product of procaine hydrochloride, by zero-crossing first-derivative spectrometry.

A first derivative spectrometric method has been developed for the determination of the para-aminobenzoic acid (PABA), a related substance and degradation product of the local anesthetic procaine hydrochloride (PH). The wavelength selected for the determination of para-aminobenzoic acid in the presence of procaine was 290 nm. At this wavelength the calibration graphs relating the amplitude of the signals to the concentration of para-aminobenzoic acid were linear up to 10 mg L(-1). The detection limit of para-aminobenzoic acid was 0.70 mg L(-1). The method is simple and rapid and does not require preliminary treatment of the sample. The method was validated.

Journal Article↗
PubMed1993

Investigation of synergism between combinations of ciprofloxacin, polymyxin, sulphadiazine and p-aminobenzoic acid.

Subinhibitory concentrations of combinations of any two of ciprofloxacin, colistin (or polymyxin B), sodium sulphadiazine and p-aminobenzoic acid were shown by checkerboard minimum inhibitory concentration determinations to have synergistic inhibitory activity against Pseudomonas aeruginosa and to have either synergistic or additive activity against Staphylococcus aureus. In addition, sulphadiazine plus either ciprofloxacin or polymyxin showed markedly enhanced killing activity against both P. aeruginosa and S. aureus. p-Aminobenzoic acid plus either ciprofloxacin or polymyxin also demonstrated enhanced killing activity against P. aeruginosa but these combinations were less effective in enhancing activity against S. aureus. Ciprofloxacin in combination with polymyxin had a marked synergistic effect against P. aeruginosa but only a slight synergistic effect against S. aureus. These findings indicate a potential usefulness for the synergistic combinations against P. aeruginosa and S. aureus in the clinical situation; that is, they indicate an extended role for sulphonamides and support a potential role for p-aminobenzoic acid as enhancers of the activity of primary antibacterial agents such as ciprofloxacin and polymyxin. We suggest that for a second antibacterial to enhance the activity of ciprofloxacin, it may be necessary for the second antibacterial to increase cell permeability so increasing bacterial uptake of ciprofloxacin.

4-Aminobenzoic Acid↗
PubMed1981

Clinical study of exocrine pancreatic function test by oral administration by N-benzoyl-L-tyrosyl-p-aminobenzoic acid.

The clinical usefulness of a simple exocrine pancreatic function diagnostic test (PFT) was examined by the oral administration of 500 mg of N-benzoyl-L-tyrosyl-p-aminobenzoic acid. Recovery of p-aminobenzoic acid (PABA) in the urine was significantly lower in patients with calcifying chronic pancreatitis (58.6%) and noncalcifying chronic pancreatitis (68.6%) than in healthy normal subjects (81.0%; p less than 0.001 and p less than 0.05, respectively). Abnormally low values were demonstrated in 15 out of 19 (78.9%) chronic pancreatitis cases. In comparing the PFT with the pancreozymin secretin test, a good correlation (P less than 0.001) with maximum bicarbonate concentration was detected. In cases which were abnormal with respect to the PFT, the recovery rate of PABA was increased by the administration of antacids or digestive enzyme preparations (average increase of 24.1 or 29.8%, respectively). These results suggest that this test is also useful for the evaluation of therapeutic effects in patients with pancreatic diseases.

4-Aminobenzoic Acid↗
PubMed1977

Study on the exocrine pancreatic function by the oral administration of N-benzoyl-L-tyrosyl-para-aminobenzoic acid.

N-benzoyl-L-tyrosyl-p-aminobenzoic acid (Bz-ty-PABA) was orally administered to 11 controls, 10 patients with chronic pancreatitis, 7 patients with diabetes mellitus and 6 patients with liver cirrhosis. The cumulative 6 h recovery rate of PABA in the urine was significantly lower (P less than 0.005) in patients with chronic pancreatitis (49.1 + or - 10.1 percent), diabetes mellitus (50.4 + or - 20.4 percent) and liver cirrhosis (52.5 + or - 13.0 percent) than in the control group (79.5 + or - 12.0 percent) (mean + or -S.D.). This test is considered to be useful in the diagnosis of pancreatic exocrine insufficiency, especially in chronic pancreatitis. Patients with diabetes mellitus frequently has demonstrable abnormality of pancreatic exocrine function. Liver cirrhosis causing severe impairment of liver functions seemed to interfer with the elimination of PABA.

4-Aminobenzoic Acid↗
PubMed2005

Crystal structures and spectroscopic properties of zinc(II) ternary complexes of vitamin L, H' and their isomer m-aminobenzoic acid with bipyridine.

The crystal structures of the three Zn(II) complexes, [Zn(bpy)(o-AB)2] (1) (bpy=2,2'-bipyridine, o-AB=o-aminobenzoic acid=Vitamin L), [Zn(bpy)(m-AB)Cl]2 (2) (m-AB=m-aminobenzoic acid), [Zn(bpy)(p-AB)Cl]*p-AB*H2O (3) (p-AB=p-aminobenzoic acid=Vitamin H'), have been determined and the basic coordination geometries and architectures organized by hydrogen-bonds and pi-pi interactions also characterized. The substitute amine group at ortho-, meta-, and para-position of AB plays an important role to produce completely different coordination motif of these complexes, further, in all complexes, aromatic amines are not coordinated to Zn(II) atom. While two different types of coordination modes of the carboxylate O atoms are present in these complexes: one mode consists of the usual Zn-O bond lengths (2.009(2)-2.251(2) A) in complex 1, 2 and 3; another consists of a very long Zn-O bond lengths (2.422(2) A) in complex 1. Each of the complexes has the characteristic UV absorption bands around 250-310 nm region, and the intense fluorescence band at near 325 nm.

4-Aminobenzoic Acid↗
PubMed1983

Nonpancreatic hydrolysis of N-benzoyl-L-tyrosyl-p-aminobenzoic acid (PABA peptide) in the rat small intestine.

Factors affecting the intestinal hydrolysis of orally administered N-benzoyl-L-tyrosyl-p-aminobenzoic acid (PABA peptide) and urinary recovery of p-aminobenzoic acid have been studied in rats, after diversion of the pancreatic and biliary secretions. The exclusion of pancreatic secretions from the small intestine lowered, but did not completely abolish, the urinary recovery of PABA, whereas diversion of the bile had no significant effect. A particulate-bound enzyme capable of splitting PABA peptide was found to be present throughout the rat small intestine, and its activity remained unchanged in the absence of biliopancreatic secretions. The intestinal PABA peptide hydrolase could be solubilized with papain and Triton from a partially purified brush-border membrane fraction, and it eluted in gel filtration as a high-molecular-weight peak, well separated from the other known peptidases of the intestinal brush-border membrane.

4-Aminobenzoic Acid↗
PubMedDate not supplied

Simultaneous determination of p-aminobenzoic acid and its metabolites in urine by high performance liquid chromatography.

We developed a new HPLC method for the determination of p-aminobenzoic acid (PABA) and its metabolites (p-aminohippuric acid, N-acetyl-p-aminohippuric acid, N-acetyl-p-aminobenzoic acid) in urine. As the internal standard m-hydroxybenzoic acid was used. In the isocratic elution the mobile phase consisted of methanol and 0.02 M ammonium acetate (20:80 v/v, pH 4.0). The separation was carried out on the C18, reversed-phase column, particle size 5 microns. The separated components were detected at 280 nm. The method can be used in the assessment of the response of pancrease (secretion of digestive enzymes) to soya feeding as well as in the diagnosis of the exocrine pancreatic diseases of animals.

4-Aminobenzoic Acid↗
PubMed1989

Origin of p-aminobenzoic acid from chorismic rather than iso-chorismic acid in Enterobacter aerogenes and Streptomyces species.

Enzyme extracts from Enterobacter aerogenes (62-1), Streptomyces aminophilus, and Streptomyces coelicolor were used to investigate the biosynthesis of p-aminobenzoic acid. The enzyme preparations from E. aerogenes and S. aminophilus contained both p-aminobenzoate synthase and iso-chorismate synthase activity, and were able to convert both chorismic and iso-chorismic acid to p-aminobenzoic acid. The apparent KM for chorismic acid was, however, significantly lower than that for iso-chorismic acid, while the Vmax was identical for both substrates in both enzyme systems. The enzyme preparations from S. coelicolor did not contain iso-chorismate synthase activity and p-aminobenzoic acid synthesis took place in this system from chorismic acid only. It is concluded that iso-chorismic acid is not an obligatory intermediate in p-aminobenzoic acid biosynthesis in these organisms.

4-Aminobenzoic Acid↗
PubMed1988

[The action of aminobenzoic acid derivatives on the ion currents in myelinated nerves. 1. Dose-response relationship].

Effects of Aminobenzoic Acid Derivatives on the Ionic Currents in Myelinated Nerve/1st Communication: Dose-response curves Derivatives of aminobenzoic acid were modified and their blocking potencies on the ionic currents of single potential clamped myelinated nerve fibres were tested by means of dose-response curves. Starting from metacaine (ethyl m-aminobenzoate), derivatives of different basicity were produced by N-dimethylization, N-quarternization and by preparing a corresponding aliphatic amine. The corresponding free acids and the structural isomers of metacaine were tested as well. The physico-chemical properties of the derivatives were characterized by their pKa-values and their octanol/water partition coefficients. Our findings suggest that the site of action of the aminobenzoic acids tested is located at the inside of the nerve membrane. Moreover, no indications of binding to a receptor in a pharmacological sense were found.

Aminobenzoates↗
PubMed1980

A new method of testing pancreatin therapy in vivo by the use of a peroral chymotrypsin substrate 4-(N-acetyl-L-tyrosyl)aminobenzoic acid.

The efficacy of pancreatin in vivo was determined in 14 patients with advanced pancreatic insufficiency using a peroral test with 2 g of chymotrypsin substrate, 4-(N-acetyl-L-tyrosyl)aminobenzoic acid, the Lundh test meal and 1000 ml tea. Chymotrypsin hydrolysis was quantified by 4-aminobenzoic acid excreted in 6-hr or 8-hr urine samples. After a control test without pancreatin, one or two tablets of Panpur (Nordmark-700 mg of pancreatin and 50 mg of bile per tablet) were applied simultaneously with the Lundh meal on repeated examinations. The urinary excretion of 4-aminobenzoic acid was restored to normal values in 5 subjects during both sampling periods. With this method, stimulated and substituted chymotrypsin is measured at the same time. The conditions of the tests, both with and without pancreatin replacement, are fully comparable and thus the significance of factors modifying the activity of enzymic components in the digestive tube is limited. The method appears appropriate for the institution of an effect pancreatin therapy and its control in vivo.

4-Aminobenzoic Acid↗
PubMed1975

Aminobenzoic acid diuretics. 7. 3-Substituted 4-phenyl-, 4-arylcarbonyl-, and 4-arylmethyl-5-sulfamoylbenzoic acids and related compounds.

Various 4-substituted 3-alkylamino-, 3-alkoxy-, 3-alkylthio-, and 3-alkyl-5-sulfamoylbenzoic acids related to known aminobenzoic acid diuretics were synthesized and screened for their diuretic properties in dogs. The tabulated results from a 3-hr test period revealed that generally the diuretic profile and potency could be retained when 3-alkoxy, 3-alkylthio, and 3-phenethyl were substituted for the 3-alkylamino moiety. The high potency of several 3-alkoxy-, 3-alkylthio-, and 3-phenethyl-4-benzoyl-5-sulfamoylbenzoic acids confirmed previous suggestions that the apparent diuretic effect of 4- and 5-alkylamino-6-carboxy-3-phenyl-1,2-benzisothiazole 1,1-dioxides originates from the corresponding 4-benzoyl-5-sulfamoylbenzoic acid derivatives due to an existing equilibrium in plasma. 4-Benzoyl-5-sulfamoyl-3-(3-thenyloxy) benzoic acid (118) is among the most potent benzoic acid diuretics hitherto synthesized and shows significant diuretic activity in dogs at 1 mug/kg. The results obtained with different 3-substituted 4-phenyl-5-sulfamoylbenzoic acids supported the earlier concept regarding the steric influence of the 4-substituent on the diuretic potency of sulfamoylbenzoic acid diuretics.

Aminobenzoates↗
PubMedDate not supplied

[Study of interferon-inducing activity of para-aminobenzoic acid injected subconjunctivally in rabbits].

Para-aminobenzoic acid (PABA) is an early interferon inductor. The present study assesses the interferon-inducing activity of PABA (0.007 and 0.06% solutions) and poludan (Poly A:U) injected subconjunctivally to rabbits. Interferon (If) titer in the conjunctival washings and anterior chamber humor was assessed 4-48 h after injection of If inductors. After the first injection of 0.007% PABA, If titer in the conjunctival washings was constantly increasing and reached the maximum after 48 h (64-128 U/ml). Repeated injection of PABA after 5 days still more stimulated the production of If, with the peak after 24 h (128 U/ml); after 48 h the titer of If was still high. If titers induced by 0.007% PABA and poludan were compatible after both injections in the conjunctiva but not in the anterior chamber humor. With poludan, the maximum If titer (16 U/ml) was observed 6 h postinjection, after which it was no longer detected, while after PABA the maximum If titer (64 U/ml) was observed during the 4th and 12th hours postinjection and then decreased, remaining rather high after 24 h. After 0.06% PABA, If titers were 2-4 times lower in all experiments than after 0.007% PABA. The detected interferon-inducing activity of PABA suggests its therapeutic efficacy in ocular diseases involving disorders in If production.

4-Aminobenzoic Acid↗
PubMed1989

Evaluation of two forms of N-benzoyl-L-tyrosyl p-aminobenzoic acid in pancreatic function testing of dogs.

Plasma para-aminobenzoic acid (PABA) concentrations were compared in 12 dogs after oral administration of either a powdered suspension or a solution of N-benzoyl-L-tyrosyl-PABA. Peak PABA plasma concentrations were significantly higher at 30, 60 and 90 minutes after administration of the solution (P less than 0.05). As the solution may now be used as a clinical test, interpretation of the results by comparison with normal absorption curves obtained after administration of the suspension could contribute to a failure to diagnose canine exocrine pancreatic insufficiency.

4-Aminobenzoic Acid↗