Tocoyena formosa, a small ornamental tree growing in the dry regions of central Brazil, is commonly known as 'genipapo do bravo'. This is a medicinal plant traditionally used as an analgesic for rheumatic pain, lower back pain and myalgia, however its use is carried out without scientific evidence, which thus justifies the development of studies to investigate and prove its therapeutic potential. Therefore, the objective of this study was to evaluate the phytochemical profile of Tocoyena formosa (Cham. & Schlecht.) K. Schum (TFLHE) and the mechanisms involved in its anti-nociceptive effect. The TFLHE revealed the presence of gallic acid, catechin, chlorogenic acid, caffeic acid, ellagic acid, rutin, quercetin and luteolin. The TFLHE at doses of 200 and 400mg/kg significantly decreased acetic acid-induced abdominal contortions, the reaction time for the formalin test in both phases and increased the paw withdrawal time in the hot plate thermal stimulus test. The 200mg/kg dose also significantly inhibited the plantar mechanical hyperalgesia intensity induced by formalin within 24h.
Treatment: with the TFLHE did not cause significant changes in motor performance and coordination in the Rota Rod test. The investigation on the possible mechanism of antinociceptive action of TFLHE indicates the involvement of opioid, glutamatergic, nitric oxide/cGMP and vanilloid systems. It is concluded that the TFLHE has an antinociceptive effect promoted by the aforementioned mechanisms.
Keywords: Glutamate; Nitric oxide; Nociception; Opioid; Tocoyena formosa; Vanilloid.
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