Pharmacological effects of protocatechuic acid and its therapeutic potential in neurodegenerative diseases: Review on the basis of in vitro and in vivo studies in rodents and humans

Protocatechuic acid has very promising properties potentially useful in the inhibition of neurodegenerative diseases progression. It is the main metabolite of the complex polyphenolic compounds and is believed to be responsible for beneficial effects associated with consumption of the food products rich in polyphenols. Protocatechuic acid is present in the circulation significantly longer and at higher concentrations than parent compounds and easily crosses the blood brain barrier. The aim of the following paper is to provide an extensive and actual report on protocatechuic acid and its pharmacological potential in prevention and/or treatment of neurodegenerative diseases in humans based on existing data from both in vitro and in vivo studies. Experimental studies strongly support the role of protocatechuic acid in the prevention of neurodegenerative processes, including Alzheimer's and Parkinson's diseases, due to its favorable influence on processes underlying cognitive and behavioral impairment, namely accumulation of the β-amyloid plaques in brain tissues, hyperphosphorylation of tau protein in neurons, excessive formation of reactive oxygen species and neuroinflammation. There is a growing evidence that protocatechuic acid may become in the future efficacious and safe substance that protects against neurodegenerative disorders.