Parabens (para-hydroxybenzoic acid esters) are the popular antimicrobial preservative added to foods, pharmaceuticals and personal care products. Due to their huge usage and estrogen effects, environmental fate and their metabolites have drawn wide attention. Hydrolysis catalyzed by enzymes is considered to be the major degradation pathway for ester compounds in organism in vivo. However, transesterification of parabens has been proved to be occurred in liver and small-intestinal microsomes of rat and humans, in the presence of alcohols. In this work, transesterification of parabens in garden bean sprouts (Pisum sativum Linn.) was studied by spraying with parabens (5 mg/L of ethyl paraben, propyl paraben, and butyl paraben) and alcohols (0.5%, v/v) every 12 hours. The highest concentration of emerging methyl paraben (MeP) was determined when the sprouts were exposed to ethyl paraben, with the production ratio of 55.4% (Fig. 1). Lower efficient transesterification of parabens was found when the sprouts were exposed to propyl and butyl parabens. The emerging MeP declined significantly with the environmental methanol level decreased from 0.5% to 0.005%, indicating that transesterification efficiency is limited to methanol concentration.

New transformation pathway of parabens in plants: Transesterification with alcohols

256th National Meeting (2018)

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