Salicylate Assay Kit (Colorimetric)

Salicylates (salts of 2-hydroxybenzoic acid) are common non-steroidal anti-inflammatory drugs (NSAIDs) with anti-pyretic and mild analgesic effects. Originally discovered in willow tree bark, salicylate has been used in an ethnopharmacological context for millennia to treat inflammation and fever. The most frequently used modern salicylate drug is aspirin (acetylsalicylic acid), which is rapidly hydrolyzed to salicylate in both the gastrointestinal tract and bloodstream. Salicylate acts as a weak inhibitor of the proinflammatory COX-2 enzyme, which is thought to underlie its anti-inflammatory effect in chronic aspirin therapy. However, supratherapeutic blood salicylate levels can cause severe intoxication and poisoning. Serum salicylate levels are monitored in people taking chronic high-dose aspirin for arthritis and in suspected cases of aspirin overdose. Therapeutic serum levels for salicylate range from 50-250 μg/ml (0.36 – 1.8 mM) in individuals on chronic aspirin therapy. Levels over 300 μg/ml (2.17 mM) are considered toxic, resulting in dose-dependent and potentially lethal symptoms such as tinnitus/deafness, lethargy/coma, seizures and metabolic acidosis. BioVision’s Salicylate Assay Kit is a high-throughput adaptable microplate-based assay that allows for rapid quantification of salicylate levels in biological fluids. In our assay, salicylate is enzymatically metabolized to catechol, with concomitant oxidation of a cofactor, resulting in a decrease in absorbance at OD = 405 nm that is proportional to the concentration of salicylate present. The assay is not affected by other NSAIDs and has an LOQ of 0.19 mM with a reliable linear range from 1 – 20 nmole salicylate per well (corresponding to 0.2 – 4 mM salicylate in undiluted samples)