Lam. crude extract presents antinociceptive effect on an arthritic pain model in mice.

Arthritis is a chronic inflammatory disease which reduces the life quality of affected individuals. Therapeutic tools used for treating inflammatory pain are associated with several undesirable effects. Lam., known as 'Barbasco' or 'Cambara', is mostly used in several disorders and possesses antirheumatic, anti-inflammatory, and analgesic properties. Here, we investigated the antinociceptive and anti-inflammatory effects of the crude extract applied orally and topically in acute pain models and an arthritic pain model induced by complete Freund's adjuvant (CFA) paw injection in male mice (25-30 g). The high-performance liquid chromatography (HPLC) of the extract crude revealed the presence of the lupeol, stigmasterol, and β-sitosterol. The stability study of the gel did not show relevant changes at low temperatures. The oral treatment with the extract prevented the capsaicin-induced spontaneous nociception and the acetic acid-induced abdominal writhing, but did not alter the thermal threshold in the tail immersion test. The antinociceptive effect was not reversed by naloxone in the capsaicin test. The oral or topical treatment reversed the CFA-induced mechanical allodynia and thermal hyperalgesia with maximum inhibition () of 69 ± 6 and 68 ± 5% as well as 78 ± 15 and 87 ± 12%, respectively. Moreover, the topical but not oral treatment inhibited the CFA-induced cell infiltration, but did not reduce the paw edema significantly. The oral treatment with did not cause adverse effects. These findings suggest that the oral or topical treatment with presents antinociceptive actions in an arthritic pain model without causing adverse effects.