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PubMedDate not supplied

[Antithrombotic activity of para-aminobenzoic acid].

Mechanisms of the anticoagulant activity of p-aminobenzoic acid (PABA) were studied. The specific antithrombin activity of PABA is aIIa = 7.00 +/- 0.32 IU/mg and the specific antiactivated factor Xa activity is aXa = 6.70 +/- 0.12 IU/mg. Study of the antithrombotic activity of PABA in rats with a model of venous stasis showed that intravenous injection of PABA at a dose of 1.5 mg/kg prevented the experimental thrombosis development 1.5 h after injection. The activity exhibited a peak 3 h after drug injection and ceased by the 5th hour. Equal antithrombotic activity in the rat blood plasma was observed for fraxiparin at a dose of 40 aXa IU/kg and PABA at 25 aXa IE/kg (1.5 mg/kg). At the same time, PABA affected neither the number of thrombocytes nor their response to the thrombocyte aggregation factors (ADP or adrenaline).

4-Aminobenzoic Acid↗
PubMedDate not supplied

[Comparative assessment of antioxidant activity of para-aminobenzoic acid and emoxipin in retina].

Effect of para-aminobenzoic acid (PABA) on lipid peroxidation (LPO) in rat and guinea pig retina exposed to hypoxic hypoxia is studied. PABA was injected intraperitoneally and parabulbarly before and after hypoxic exposure. Antioxidant activities of PABA and emoxipin were compared. An intraperitoneal injection of PABA in a dose of 10 mg/kg 24 h before hypoxia virtually completely prevented accumulation of lipid peroxides and preserved catalase activity in the retina. Parabulbar injection of 0.01% PABA solution 1 h before hypoxia prevented LPO intensification, stabilized catalase activity in hypoxia, and protected the retina starting from the moment immediately after hypoxic exposure. The efficacy of 0.01% PABA is comparable with that of 1% emoxipin, and a 0.01% solution of emoxipin is less effective than PABA in the same concentration. PABA exerts an antioxidant effect after hypoxia by decreasing the abnormally high level of lipid peroxides and reducing catalase activity in the retina after parabulbar injection of the drug. All the studied concentrations of the drug (from 0.007 to 0.08%) are active, but the optimal dose for the retina is 0.04%. By its efficacy this concentration is equivalent to 1% emoxipin.

4-Aminobenzoic Acid↗
PubMed1999

Metabolic kinetics of p-aminobenzoic acid in rabbits.

The metabolic kinetics of p-aminobenzoic acid (PABA) in rabbits was studied. PABA is predominantly metabolized by acetylation and glycine conjugation to form p-acetamidobenzoic acid (PAABA), p-aminohippuric acid (PAHA), and p-acetamidohippuric acid (PAAHA). After PABA IV administration (20 mg/kg) to rapid (n=16) and slow (n=8) acetylation rabbits, PABA was eliminated rapidly. The half-lives of PABA were 7.01+/-0.32 min in rapid acetylation rabbits and 7.08+/-0.78 min in slow acetylation rabbits. Significant differences were obtained in formation of PAABA and PAHA formed from PABA in both acetylation phenotype rabbits. The formation fraction of PAABA, formed by acetylation of PABA, was 0.8029+/-0.0267 in rapid acetylators and 0.2385+/-0.0428 in slow acetylators (p<0.001). PAHA formed from PABA was 0.0462+/-0.0102 in rapid acetylators and 0. 6652+/-0.0562 in slow acetylators (p<0.001). Only 0.0156+/-0.0030 of PABA could be detected as PAAHA in rapid acetylation rabbits which was obtained by acetylation of PAHA. After individual IV injection of PAHA, PAAHA, and PAABA to both phenotypes of rabbits, PAABA and PAAHA were eliminated in their unchanged forms whereas PAHA was further acetylated to form PAAHA. The formation fraction of PAAHA formed from the acetylation of PAHA was 0.4408+/-0.0570 in rapid acetylators and 0.0539+/-0.0084 in slow acetylators (p=0.002). From the results obtained, metabolic pathways of PABA show significant differences in both acetylation phenotypes of rabbits. Acetylation is the major metabolic route of PABA in rapid acetylation rabbits, while glycine conjugation is more predominant in slow acetylation rabbits.

4-Aminobenzoic Acid↗
PubMed2005

Theoretical and experimental studies of water complexes of p- and o-aminobenzoic acid.

We report studies of supersonically cooled water complexes of p- and o-aminobenzoic acid with one or two water molecules using two-color resonantly enhanced multiphoton ionization (REMPI) spectroscopy. Density functional theory calculations are carried out to identify structural minima of water complexes in the ground state. According to the calculation, water molecules are bound to both the C=O and -OH groups to form a cyclic hydrogen-bond network in the most stable isomer. Vibrational frequency calculations for the first electronically excited state of the most stable isomer agree well with the experimental observation. On the basis of this agreement, we believe that only one isomer exists in our molecular beam. The frequency shifts of a few normal modes caused by the water molecules further confirm the site of water addition. A surprising observation is that, for OABA(H2O)n complexes, abundant intermolecular vibrational modes are clearly observable in the REMPI spectra, while for PABA(H2O)n complexes, these modes are conspicuously missing. A red shift in the transition energy is observed for OABA(H2O)1, while blue shifts are observed for the rest of the complexes. This difference alludes to the relative stabilities of the water complexes of the two aminobenzoic acids in both the ground and excited electronic states. These observations will be discussed in comparison with those from the meta isomer.

Journal Article↗
PubMedDate not supplied

[Effect of para-aminobenzoic acid on the development of rat embryos when applied to pregnant females].

In order to study the effects of para-aminobenzoic acid (PABA) on embryonic development, the pregnant rats were injected intraperitoneally daily with 0.3% PABA at 5 mg/kg (0.3 ml/200 g): in group 2 during the preimplantation period (days 1-6 of pregnancy), in group 3 during the period of organogenesis (days 6-16), and in group 4 during days 1-16. In group 5, PABA was injected intraperitoneally (at 15 mg/kg (0.3 ml/200 g, three times a day) during days 6-16 of pregnancy and in group 6, intragastrically as a suspension at 50 mg/kg during days 1-16. In the control (group 1), saline was injected intraperitoneally at 0.3 ml/200 g during days 1-16 of pregnancy. Autopsy of the females, counting of the number of yellow bodies and implantation sites and of the number of resorbed and died fetuses, and evaluation of development of the fetuses with an account of their mass, parieto-coccygeal size and placenta mass were performed on day 20 of pregnancy. Para-aminobenzoic acid at all tested doses does not exert a damaging effect and does not affect organogenesis. At doses 5 and 15 mg/kg, PABA does not affect growth but reduces the scattering of the extreme values of the parieto-coccygeal size and body mass, thus reflecting normalization of the growth of fetuses within the litter. At a dose of 50 mg/kg, the increase of body mass of the fetuses is insignificantly diminished (p < 0.05), which is usually normalized during postnatal development.

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PubMedDate not supplied

Metabolism of sulfadimidine, sulfanilamide, p-aminobenzoic acid, and isoniazid in suspensions of parenchymal and nonparenchymal rat liver cells.

Suspensions of isolated liver cells were prepared from rat livers perfused with Ca++-free buffer and 0.05% collagenase. Primary cell suspensions (containing both parenchymal and nonparenchymal liver cells) metabolized sulfadimidine, sulfanilamide, p-aminobenzoic acid, and isoniazid approximately at first order kinetics for at least 4 hr. Suspensions of parenchymal cells had the same metabolic capacity, although the metabolism of isoniazid proceeded at a somewhat reduced rate compared to the primary cell suspensions. Suspensions of nonparenchymal cells did not metabolize sulfadimidine, sulfanilamide, or p-aminobenzoic acid during 4 hr, although such suspensions acted upon isoniazid to some degree. It was concluded that parenchymal rat liver cells may metabolize (acetylate) all four drugs tested, whereas nonparenchymal cells metabolize only isoniazid to any considerable extent.

4-Aminobenzoic Acid↗
PubMed1978

Allergic contact photodermatitis to para-aminobenzoic acid.

Allergic photocontact dermatitis developed in a patient to a commercial sunscreen preparation containing para-aminobenzoic acid (PABA) in an alcohol base. Photopatch testing showed photosensitivity to PABA. Sensitization could only be detected when PABA was tested in an alcohol vehicle; a photopatch test to PABA in petrolatum was negative.

4-Aminobenzoic Acid↗
PubMed1996

Detection and determination of the hydrazo and azo photoproducts of 4-aminobenzoic acid by high-performance liquid chromatography.

The photochemistry of 4-aminobenzoic acid has been investigated using two validated reversed-phase HPLC methods. Up to nine photoproducts have been detected, with chromatographic evidence for the formation of 4,4'-azobenzenedicarboxylic acid and 4,4'-hydrazobenzenedicarboxylic acid. The synthesis and analytical characterization of 4,4'-hydrazobenzenedicarboxylic acid is reported.

4-Aminobenzoic Acid↗
PubMed2000

The 1:1 adduct of 4-aminobenzoic acid with 4-aminobenzonitrile.

The 1:1 adduct of 4-aminobenzoic acid (PABA) with 4-am-inobenzonitrile (PABN), C(7)H(7)NO(2).C(7)H(6)N(2), consists of a primary centrosymmetric cyclic hydrogen-bonded PABA dimer interaction [O.O 2.640 (3) A] peripherally linked into chains by weaker hydrogen bonds via a head-to-tail PABN interaction [N.N 3.179 (4) and N.O 3.062 (4) A], and is linked between the chains by amine-N (PABN) to amine-N (PABA) interactions [N.N 3.233 (5) A]. No proton transfer occurs.

4-Aminobenzoic Acid↗
PubMed2002

Determination of nicotinamide and 4-aminobenzoic acid in pharmaceutical preparation by LC.

A rapid, precise and time saving high performance liquid chromatographic method has been developed and validated for the simultaneous determination of nicotinamide and 4-aminobenzoic acid in pharmaceutical preparation. The method involves isocratic elution of mobile phase through column in a reverse phase chromatography with UV detection at 254 nm. The ranges of quantification for nicotinamide and 4-aminobenzoic acid were 11-34 microg ml(-1) and 37-113 microg ml(-1), respectively. Investigating specificity, linearity, precision, accuracy, robustness and ruggedness performed the validation of the method.

4-Aminobenzoic Acid↗
PubMed1981

Assessment of exocrine pancreatic function by oral administration of N-benzoyl-L-tyrosyl-p-aminobenzoic acid (Bentiromide): 5 years' clinical experience.

Exocrine pancreatic function was assessed in 588 subjects by oral administration of 1 g of the chymotrypsin-labile peptide N-benzoyl-L-tyrosyl-p-aminobenzoic acid (Bentiromide) from 1974 to 1979. The pancreatic function test (PFT) was performed in 126 controls, 217 patients with pancreatic diseases, 196 patients with various non-pancreatic gastrointestinal disease, 18 patients with renal disease and 31 patients with various other diagnoses. In 62 of 72 patients (86 per cent) with chronic pancreatitis and in 19 of 25 (76 per cent) with pancreatic carcinoma, the excretion of p-aminobenzoic acid (PABA) in the urine was significantly less than in the controls. In contrast, 328 of 353 controls and patients with non-pancreatic diseases (93 per cent) had PABA excretion within normal limits. The sensitivity and specificity of the Bentiromide-test observed in this study is sufficient to detect moderate to severe disturbances of pancreatic exocrine function. The PFT has proved to be an easy and reliable screening test for pancreatic exocrine function in ambulatory as well as in hospitalized patients.

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PubMed1992

Bentiromide test using liquid-chromatographic measurement of p-aminobenzoic acid and its metabolites for diagnosing pancreatic insufficiency in childhood.

We assessed the diagnostic capability of the bentiromide test using a high-pressure liquid-chromatography method to analyze p-aminobenzoic acid and its metabolites in plasma as an indirect measure of exocrine pancreatic function. Mean total amine concentration in pancreatic-insufficient subjects was significantly lower than in control subjects. There were 3 of 15 false-negative results and no false-positive results. We conclude that this chromatographic method is an effective means of analyzing p-aminobenzoic acid and its metabolites after ingestion of bentiromide.

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PubMed1989

Interaction of p-aminobenzoic acid with erythrocyte membrane: photoaffinity labeling of the binding sites.

p-Aminobenzoic acid (PABA) was found to prevent eichinocytosis of red cells in vitro. Equilibrium binding studies with right-side-out membrane vesicles revealed a similar number of binding sites and Kd values for both normal and sickle cell membranes. A [14C]Azide analog of PABA was synthesized as a photoaffinity label to probe its sites of interaction on the erythrocyte membranes. Competitive binding studies of PABA with its azide indicated that both the compounds share common binding sites on the membrane surface. The azide was found to covalently incorporate into the membrane components upon irradiation; 52-35% of the label was associated with the proteins and the remaining with the lipids. Electrophoretic analysis of photolabeled membranes revealed that the azide interacts mainly with Band 3 protein in the case of intact erythrocytes and right-side-out sealed vesicles; however, if unsealed ghosts are used, other membrane proteins besides Band 3 are photolabeled. PABA was found to inhibit both high and low affinity calcium-binding sites situated on either surface of the membrane apparently in a non-competitive manner. However, calcium binding stimulated by magnesium and ATP was only slightly affected. Calcium transport into inside-out vesicles was inhibited by PABA, but it did not affect the calcium ATPase activity.

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PubMed1985

Effects of p-aminobenzoic acid, methionine, threonine and protein levels on susceptibility of mice to Plasmodium berghei.

The effects of dietary p-aminobenzoic acid (PABA), protein, methionine and threonine on Plasmodium berghei infection in mice were investigated. Animals were fed diets containing 12 or 20% casein supplemented with PABA (0 or 2 mg/kg diet), methionine (0 or 15 mg/g casein) and threonine (0, 7.5, 27.5 or 47.5 mg/g casein). Percent mortality was lower in rats fed diets without PABA than in those fed diets containing PABA. All further experiments were conducted without supplemental PABA. While the mean day of death was greater in the groups fed 12% casein, percent mortality in these groups was nearly twofold higher than in the groups fed 20% casein. The presence or absence of 15 mg methionine per gram casein had no effect on percent mortality, mean day of death, or percent parasitemia, regardless of dietary casein level. Supplementation of threonine at any level to the 12% casein diet with supplemental methionine resulted in mortality rates similar to those from animals fed the 20% casein diets, but percent mortality was not altered by threonine in the absence of supplemental methionine. The mean day of death of animals fed 20% casein increased with increments of added threonine. Methionine had no influence on this phenomenon. It is concluded that the quantity of dietary protein and the quality of its amino acid composition can have profound effects on the susceptibility of mice to malaria.

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PubMed1987

Antimutagenic effect of p-aminobenzoic acid on the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine in Salmonella typhimurium.

p-Aminobenzoic acid (PABA) exhibited antimutagenic activity toward N-methyl-N'-nitro-N-nitrosoguanidine(MNNG)-induced mutagenicity in the Ames assay in Salmonella typhimurium. The antimutagenic effects were associated with an increased rate of decomposition of MNNG in the presence of PABA. The participation of other mechanisms, such as the alteration of cellular processes by PABA, however, cannot be excluded.

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PubMed1978

Hydrolysis and metabolism of N-benzoyl-L-tyrosyl-p-aminobenzoic acid in normal and pancreatic duct-ligated animals.

Hydrolysis and metabolism of N-benzoyl-L-tyrosyl-p-aminobenzoic acid (Bz-ty-PABA), a synthetic peptide used for the assessment of exocrine pancreatic function, were studied in normal and pancreatic duct-ligated rats and guinea pigs. Bz-ty-PABA was specifically cleaved by chymotrypsin to N-benzoyl-L-tyrosine and p-aminobenzoic acid (PABA) in mucosal homogenates of the intestine. Both of the resultant products were rapidly absorbed and excreted in the urine after oral administration of two kinds of radioactive Bz-ty-PABA (Bz[14C] and PABA[14C]) to animals. The absorption rate was correlated to the intestinal chymotrypsin activity obtained from in vitro studies. Benzoic acid and p-acetaminobenzoic acid were predominant in the urine after dosages of Bz-ty-PABA with Bz[14C] and PABA[14C], respectively, in both species. Additionally, a small amount of unchanged form of Bz-ty-PABA was excreted in the urine and bile without being cleaved by chymotrypsin. These results and the study using intravenous injections suggest that the absorption of this intact peptide may be almost 10% of the dose.

Aminobenzoates↗
PubMed1989

Decrease of ultraviolet-induced DNA injury in human skin by p-aminobenzoic acid esters.

The effect of a sunscreen containing a p-aminobenzoic acid (PABA) ester on ultraviolet-induced DNA injury was assessed on human epidermal cells by the measure of unscheduled DNA synthesis intensity. Our results show that DNA repair was reduced by approximately 50%. Therefore, sunscreens based on PABA esters might be expected to reduce photocarcinogenesis.

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