phydroxybenzoate

p-hydroxybenzoate refers to the para-hydroxybenzoate moiety, the conjugate base of p-hydroxybenzoic acid, or to salts and esters derived from it. In chemical terms, it is a para-substituted benzoic acid where the hydroxyl group is located opposite the carboxyl group on the benzene ring. The neutral acid, p-hydroxybenzoic acid, has the formula C7H6O3; its salts (such as sodium p-hydroxybenzoate) and esters (p-hydroxybenzoates) are common in chemistry and industry.

Occurrence and synthesis: hydroxybenzoic acids occur in plants as part of phenolic metabolism and play roles in plant defense and lignin biosynthesis. Commercially, p-hydroxybenzoate derivatives are produced or isolated as intermediates for various applications. The ester form, p-hydroxybenzoate, is especially well known as the basis for a family of compounds collectively called parabens.

Uses and applications: p-hydroxybenzoates are widely used as preservatives in cosmetics, pharmaceuticals, and some foods in the form of esters such as methylparaben, ethylparaben, propylparaben, and butylparaben. These esters are valued for antimicrobial properties and shelf-life extension. The anion and related salts also serve as intermediates in organic synthesis, dye manufacture, and polymer chemistry. Regulatory status varies by jurisdiction and product category, reflecting ongoing safety assessments and environmental considerations.

Safety and regulation: parabens have been the subject of extensive review. While most health authorities permit their use within established limits, some studies have raised concerns about potential endocrine activity, leading to restrictions in certain products or markets.