Vanillin derivatives affecting the central and peripheral nervous system

Nowadays, a significant number of antiepileptic drugs aimed at influencing the main inhibitory transmitter – gamma-aminobutyric acid (GABA). Compounds with various chemical structures, binding to different GABA_A sites, potentiate the action of amino acid. Recent studies have reported that phenolic compounds such as vanillin and its derivatives also have actions within the CNS and act as enhancer of GABA potential. On the other hand, vanillin affects the peripheral nervous system as agonist of TRPV1 channels that are involved in the transmission and modulation of pain (nociception) as well as the integration of diverse painful stimuli. At the present study, the influence of vanillin and its derivatives (vanillin oxime, vanillyl alcohol and vanillic acid) on the central and peripheral nervous system was reliably confirmed by evaluating their anticonvulsant, antidepressant and analgesic activity. The present findings indicate that all aforementioned compounds possess antiseizure action after oral administration on PTZ-induced convulsion model. Antidepressant activity, studied by forced swimming test (FST), has been more pronounced manifested for vanillin and vanillic acid during 24 hours after administration. Intriguingly, TRPV1 agonist vanillin and its oxime after transdermal delivery produced hyperalgesia when tested on allylisothiocyanate- and capsaicin-induced models, whereas vanillyl alcohol and vanillic acid were found to reduce the pain sensation.