Cnidoscolus quercifolius is a species native to the Brazilian Caatinga (semi-arid vegetation) popularly known as "favela" and "faveleira" and used in folk medicine to treat pain. The objective of this work was to evaluate the antinociceptive effect of the ethanolic extract from barks (Cqb-EtOH) and leaves (Cql-EtOH) of C. quercifolius in mice using experimental models of nociception. The antinociceptive activity was evaluated by writhing, hot plate and formalin tests. In addition, the rota-rod test was used to evaluate motor coordination. In the acetic acid-induced writhing test, the Cqb-EtOH (100, 200 and 400 mg/kg, i.p.) reduced the number of writhing by 83.70, 81.40 and 88.10%, respectively, while Cql-EtOH reduced by 71.30, 79.40, and 98.70%, respectively. In the formalin test, the extracts reduced the paw licking time in the fi rst and second phases, but the best results were observed in the second phase (infl ammatory pain), reducing by 66.08, 78.26 and 73.97%, as well as 60.11, 75.58, and 79.46% for Cqb-EtOH and Cql-EtOH, respectively. In the hot plate test, the extracts increased the reaction time when compared to control only at dose of 400 mg/kg. Using the rota-rod test, mice treated did not demonstrate any signifi cant motor performance changes. It can be concluded that Cqb-EtOH and Cql-EtOH of C. quercifolius have antinociceptive activity, which supports the popular use of this plant to treat pain.

Lippia grata Schauer (Verbenaceae) leaves essential oil/β‐cyclodextrin (EO/β‐CD) complex was used to evaluated if the complex formulation is able in reduces orofacial behavior in mice. Male Swiss mice were pretreated with EO/β‐CD (50, 100 and 200 mg/kg, p.o., per os, orally), morphine (5 mg/kg, i.p.) or vehicle (distilled water). Ninety minutes after the treatment, we injected formalin (20 μL, 2%), capsaicin (20 μL, 2.5 μg) or glutamate (40μL, 25 μM) into the right upper lip (perinasal area). For the action in the CNS, 90 minutes after the treatment, the animals were perfused, the brains collected, and submitted in an immunofluorescence protocol for Fos protein. Experimental protocols were approved by the Animal Care and Use Committee at the UFS (# 57/11). EO/β‐CD produced significant (p< 0,05; p<0.01) antinociceptive effect, in the formalin‐, capsaicin‐and glutamate‐induced orofacial nociception. The immunofluorescence showed that the EO/β‐CD activated significantly (p<0.05) the olfactory bulb, the piriform cortex, and the periaqueductal grey of the CNS. Together, our results provide first‐time evidence that EO/β‐CD attenuates orofacial nociception at least, in part, through an activation of CNS areas, such as periaqueductal grey.

The present study examined the anti‐hypernociceptive effect of the hecogenin (HG) in mice. For assess this effect were realized models of mechanic hypernociception induced by carrageenan (CG) and Tumor Necrosis Factor‐α (TNF‐α). The mice were pre‐treated with vehicle (saline + Tween 80 0.2%; p.o.) or HG (5, 10 and 20 mg/kg, i.p.). Thirty minutes after the treatments, were injected in region subplantar of the rear right paw: 20 μL of CG (300 μg/paw) or TNF‐α (100 pg/paw). The hypernociception was assessed in times of 0.5, 1, 2 and 3 hours after the injection of CG and TNF‐α, with digital Von Frey. It was observed that HG was able to maintain the baseline nociceptive threshold in two tests. The results suggest anti‐hypernociceptive property of HGN, probably by a mechanism inhibition of production of cytokines, which activate various reactions connected with inflammation, reducing thereby hipernociception.Financial support: FAPITEC/SE, CAPES, CNPq (Brazil).