Gentisic Acid (GA)

Gentisic acid is a dihydroxybenzoic acid. It is a crystalline powder that forms monoclinic prism in water solution. Gentisic acid is an active metabolite of salicylic acid degradation. There is an increasing amount of evidence indicating that gentisic acid has a broad spectrum of biological activity, such as anti-inflammatory, antirheumatic and antioxidant properties. Gentisic acid is also a byproduct of tyrosine and benzoate metabolism.

A method has been reported recently based on the color formed with ferric ion. This method was found unsatisfactory because the color obtained is transient, owing to the oxidation of the hydroquinone by ferric ion. In a mixture of salicylic acid and gentisic acid (4: 1) salicylic acid can be determined quantitatively by the ferric chloride method, with no interference by the gentisate.