Anti-inflammatory and antinociceptive effect of Hyptis martiusii BENTH leaves essential oil.

Hyptis martiusii Benth. also known as "cidreira brava", has some activities verified in the literature, such as antiulcerogenic, antimicrobial and antiedematogenic. This study aimed to verify the anti-inflammatory and antinociceptive effect of the leaves essential oil. For the evaluation of the anti-inflammatory activity of OEHM (100 mg/kg/p.o.), models paw edema induced by dextran and histamine, peritonitis and vascular permeability were used. Regarding the anti-nociceptive activity of the OEHM, abdominal contortion tests by acetic acid, formalin, hot plate (50.75 and 100 mg/kg/p.o.), open field and mechanical plantar hyper-nociception (100 mg/kg/p.o.) were carried out. OEHM (100 mg/kg) showed anti-inflammatory activity, being able to remarkably deducing the paw edema induced by dextran and histamine, the total number of cell leukocytes/neutrophils in peritonitis, and exudate in vascular permeability. In antinociceptive activity, the OEHM did not promote significant effect in central nervous system in the open field assay, remarkably reduced abdominal contortions (50, 75 and 100 mg/kg), the time in the formalin assay and the mechanical hyper-nociception (100 mg/kg); however, only doses between 75 and 100 mg/kg were capable of ameliorating the reponse latency time. Regarding the probable mechanism of action, the antinociceptive activity includes the participation in the activation of opioid, TRPV1, and α2-noradrenergic systems. In short, data obtained here reveal that OEHM has anti-inflammatory and antinociceptive activity, implying that its action may be involved in the mechanism of inhibition or liberation of pro-inflammatory mediators involved in pain and inflammation.

Enhancement of orofacial antinociceptive effect of carvacrol, a monoterpene present in oregano and thyme oils, by ß-cyclodextrin inclusion complex in mice.

Orofacial pain is associated with diagnosis of chronic pain of head, face, mouth, neck and all the intraoral structures. Carvacrol, a naturally occurring isoprenoid with diverse class of biological activities including anti-inflammatory, analgesic, antitumor and antioxidant properties. Now, the antinociceptive effect was studied in mice pretreatment with carvacrol (CARV) and ß-cyclodextrin complex containing carvacrol (CARV-ßCD) in formalin-, capsaicin-, and glutamate- induced orofacial nociception. Mice were pretreated with vehicle (0.9% Nacl, p.o.), CARV (10 and 20mg/kg, p.o.), CARV-ßCD (10 and 20mg/kg, p.o.) or MOR (10mg/kg, i.p.) before the nociceptive behavior induced by subcutaneous injections (s.c.) of formalin (20µl, 2%), capsaicin (20µl, 2.5µg) or glutamate (20µl, 25µM) into the upper lip respectively. The interference on motor coordination was determined using rotarod and grip strength meter apparatus. CARV-ßCD reduced the nociceptive during the two phases of the formalin test, whereas CARV did not produced the reduction in face-rubbing behavior in the initial phase. CARV-ßCD (20mg/kg, p.o.) produced 49.3% behavior pain while CARV alone at 20mg/kg, p.o, produced 28.7% of analgesic inhibition in the second phase of formalin test. CARV, CARV-ßCD and Morphine (MOR) showed a significant reduction against nociception caused by capsaicin or glutamate injection. Thus the encapsulation of carvacrol in ß-cyclodextrin can acts as a considerable therapeutic agent with pharmacological interest for the orofacial pain management.