Antinociceptive effects of the essential oil of Mentha x villosa leaf and its major constituent piperitenone oxide in mice

Mentha x villosa Huds (Labiatae) is an aromatic herb widely used in folk medicine. Since the essential oil of the herb has many pharmacological activities, including antispasmodic effects, we determined whether the oil and its major constituent, piperitenone oxide (PO), have antinociceptive activity. The essential oil of M. x villosa (EOMV) and PO administered orally at 200 mg/kg (vehicle: 0.1% Tween 80 in water) significantly reduced the writhings induced by acetic acid from control values of 59.5 ± 3.1 s (N = 10) to 31.9 ± 2.8 s (N = 10) and 23.8 ± 3.4 s (N = 10), respectively. When administered at 100 and 200 mg/kg, EOMV reduced the paw licking time for the second phase of the formalin test from the control value of 20.6 ± 2.1 s (N = 13) to 5.3 ± 2.2 s (N = 12) and 2.7 ± 1.2 s (N = 18), respectively. At 100 and 200 mg/kg, PO reduced this second phase to 8.3 ± 2.7 s (N = 12) and 3.0 ± 1.2 s (N = 10), respectively. This effect of EOMV and PO was not reversed by naloxone. EOMV and PO had no significant effect on the first phase of the formalin test. As evaluated by the hot-plate and tail immersion test, EOMV and PO, at doses up to 200 mg/kg, showed no analgesic activity. These results show that EOMV and PO have antinociceptive activity and suggest that this effect is probably an indirect anti-inflammatory effect, which does not involve the central nervous system.

Influence of gender and estrous cycle in the forced swim test in rats

The present work aimed at studying the influence of the estrous cycle in the forced swim test, an animal model of depression. For this, 44 male and female Wistar rats were divided into five groups according to the hormonal state in the first day of the study: metaestrus (N = 12), diestrus (N = 8), proestrus (N = 7), estrous (N = 6) and males (N = 11). They were housed in groups of five, with water and food ad libitum under a 12/12 h light/dark cycle. Females were screened daily for the estrous cycle. The animals were subjected to two swimming sessions in a glass cylinder with water up to 15 cm at 28±2º C. The data of the first five minutes of a 15-min first session were compared to those of a 5-min second session 24 h later. The results indicate that the latency to the first immobility was substantially reduced in the second session and was longer for females in diestrus and proestrus in the first session. The results also indicate that females in diestrus and proestrus exhibited less immobility than males in the first session; females in diestrus also exhibited less immobility than females in metaestrus. Females in metaestrus and diestrus, as well as males, did not present the decrease in total immobility times in the second session. The present results are analyzed in terms of differential effects of progesterone and estrogen on a learning component and an affective component.

Copaiba oil effect under different pathways in mice subjected to sepsis

PURPOSE: To evaluate the effects of copaiba oil administered by different routes on survival of mices subjected to cecal ligation and puncture. METHODS: Thirty two mice were distributed into four study groups (N=8): Sham group: normal standard animals; Control group: submitted a cecal ligation and puncture (CLP); Gavage group: submitted a CLP, and treat with copaiba oil by gavage; and Subcutaneous group: submitted a CLP, and treat with copaiba oil by subcutaneous injection. After the death of the histological analysis were performed. The Kaplan-Meier curves of surviving time were realized. RESULTS: All animals that received copaiba, regardless of the route used, survived longer when compared to the control group (p<0.0001), whereas the survival time ranged from 20 hours for the control group up to 32 hours for the animals of gavage group and 52 for subcutaneous group. The animals that received gavage copaiba lived about and about 20 hours unless the subcutaneous group (p=0.0042). There was no statistical difference when compared the intensity of inflammatory response (p>0.05). CONCLUSION: Prophylactic subcutaneous administration of copaiba in mice subjected to severe sepsis by cecal ligation and puncture, resulted in a survival time higher than non-use or use of this oil by gavage.