Possible Interaction: Para-aminobenzoic acid (PABA) and Sulfanilamide

“Recently, as the result of a series of investigations with growing animals and micro-organisms, the findings of Woods (8) on the interference of p-aminobenzoic acid with sulfanilamide action have been extended by Woolley (9).”

“ Sulfanilamide growth inhibition was reversed competitively by PABA and by very high concentrations of folic acid.”

“Findlay (1940), feeding 10 mg sulfanilamide and 10 mg PABA suspended in gum acacia to mice, found that PABA antagonized the chemotherapeutic action of sulfanilamide for the LGV virus injected intracerebrally.”

“Inhibition of growth by sulphanilamide can be reversed by p-aminobenzoic acid.”

“The effectiveness of p-aminobenzoic acid (PABA) in overcoming sulfanilamide (SA) growth inhibition of Escherichia coli was explained on the basis that PABA was an essential metabolite and that SA interfered with -its utilization by the cell (Woods, 1940).”

“Increasing levels of sulfanilamide in the medium competitively inhibit the utilization of PABA for growth of L. arabinosus and decrease the amount of free and combined FA compounds formed.”

“An intensive search for antagonists of most of the known metabolites began in 1940 after Woods' announced that the chemotherapeutic properties of sulfanilamide were due to competition with the structurally related metabolite, p-aminobenzoic acid.”

“Growth inhibition by the higher concentrations of PABA is competitively antagonized by SA.”

“The report of Woods’ in I940 that the bacteriostatic action of sulfanilamide was competitively prevented by p-aminobenzoic acid , which was not known a t the time to have a biological function, prompted a widespread search for chemotherapeutic agents among compounds structurally related to metabolites.”

“This, according to the theory of Woods (1940) that p-aminobenzoic acid is a specific antagonist for sulfanilamide , classified the bacteriostatic action of 2-Cl-PAB as sulfonamide activity.”