PubMed Health⌕ Search

PubMed · 10098293

The PABA story.

Abstract

The qualities of para-aminobenzoic acid (PABA) are discussed and an account is given of how it came to be the favourite sunscreen of the post World War II era. Slowly, however, dermatologists became aware that it was a fairly common sensitizer and that it tended to cross-sensitize with compounds of similar chemical structure both in contact with the skin and given as systemic drugs. Furthermore, continued exposure to chemicals of this type could lead to autoimmune responses especially systemic lupus erythematosus and dermatomyositis. Discussion of these complications from the use of PABA took place at two meetings of the Dermatological Association of Australia in 1964 and 1965, and played a part in the slow withdrawal of PABA from sunscreens.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

B S Mackie, L E Mackie. 1999. The PABA story.. https://doi.org/10.1046/j.1440-0960.1999.00319.x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Simultaneous determination of p-aminobenzoic acid and its metabolites in the urine of volunteers, treated with p-aminobenzoic acid sunscreen formulation.

p-Aminobenzoic acid (PABA) and its metabolites (p-aminohippuric acid, p-acetamidobenzoic acid, and p-acetamidohippuric acid) were detected using high-performance liquid chromatography with an electrochemical (carbon paste) detector (HPLC-ECD). For direct current (dc) mode, with the current at a constant potential, and measurements with suitable experimental parameters, a linear concentration from 0.125 to 1.80 microg/ml was found. The detection limit was approximately 2.0 ng/ml. A carbon paste coulometric detector was used to demonstrate that PABA and its metabolites are electrochemically oxidized in acidic media, and to determine, by analyzing human urine, the percutaneous absorption of PABA and its metabolites. Findings using HPLC-ECD and HPLC with an ultraviolet detector (HPLC-UV) were comparable.

4-Aminobenzoic Acid↗

Metabolism of 4-amino-3-hydroxybenzoic acid by Bordetella sp. strain 10d: A different modified meta-cleavage pathway for 2-aminophenols.

Bordetella sp. strain 10d metabolizes 4-amino-3-hydroxybenzoic acid via 2-hydroxymuconic 6-semialdehyde. Cell extracts from 4-amino-3-hydroxybenzoate-grown cells showed high NAD(+)-dependent 2-hydroxymuconic 6-semialdehyde dehydrogenase, 4-oxalocrotonate tautomerase, 4-oxalocrotonate decarboxylase, and 2-oxopent-4-enoate hydratase activities, but no 2-hydroxymuconic 6-semialdehyde hydrolase activity. These enzymes involved in 4-amino-3-hydroxybenzoate metabolism were purified and characterized. When 2-hydroxymuconic 6-semialdehyde was used as substrate in a reaction mixture containing NAD(+) and cell extracts from 4-amino-3-hydroxybenzoate-grown cells, 4-oxalocrotonic acid, 2-oxopent-4-enoic acid, and 4-hydroxy-2-oxovaleric acid were identified as intermediates, and pyruvic acid was identified as the final product. A complete pathway for the metabolism of 4-amino-3-hydroxybenzoic acid in strain 10d is proposed. Strain 10d metabolized 2-hydroxymuconic 6-semialdehyde derived from 4-amino-3-hydroxybenzoic acid via a dehydrogenative route, not via a hydrolytic route. This proposed metabolic pathway differs considerably from the modified meta-cleavage pathway of 2-aminophenol and those previously reported for methyl- and chloro-derivatives.

4-Aminobenzoic Acid↗