p-Amminobenzoic Acid as a Protective Agent in Ozone Toxicity

Abstract

The ability of p-aminobenzoìc acid (PABA) to profeet against ozone toxicity was demonstrated in two experimental systems p-Aminobenzoic acid, and the related compounds p-aminohippuric acid and anthranïlïc acid, inhibited the ozone-induced loss of activity of the enzyme acetylcholinesterase in human erythrocytes exposed in vitro to 40 ppm of ozone. Protection in vivo was demonstrated In a study in which 15 rats injected intraperitoneally with 2 ml of 20 mM PABA prior to ozone exposure died in a mean of 426 minutes as compared to a mean of 261 minutes for 15 control animals similarly exposed to 15 ppm of ozone. These findings provide additional presumptive evidence of the importance of free radicals in the mechanism of ozone toxicity. They further suggest that PABA and related compounds warrant exploration as possible protective agents in susceptible populations exposed to significant photochemical air pollution.