Effects of oral administration of EECA on the hot plate model.

<p>Control groups were composed either the vehicle or morphine (2.5 mg/kg, p.o.). Results are presented as mean ± S.D. (n = 6–10) of increase in baseline or area under the curve. Statistical significance was calculated using ANOVA with Bonferroni’s test where *< 0.005 when comparing the morphine, EECA-treated mice with the vehicle-treated group and #< 0.005 when comparing morphine-treated with EECA-treated mice. Where no error bars are shown, is the result of values being too small to be visible in the graphic.</p

Effects of oral administration of A or C on the hot plate model.

<p>Control groups were composed of vehicle or morphine (2.5 mg/kg, p.o.). Results are presented as mean ± S.D. (n = 6–10) of increase in baseline or area under the curve. Statistical significance was calculated using ANOVA with Bonferroni’s test where * < 0.005 when comparing the morphine, A or C-treated mice with the vehicle-treated group and # < 0.005 when the C- and A-treated mice were compared with the morphine-treated mice. Where no error bars are shown, is the result of values being too small to be visible in the graphic.</p

Alkaloids isolated from <i>C</i>. Aztec-Pearl.

<p>Alkaloids isolated from <i>C</i>. Aztec-Pearl.</p

Effects of different antagonists on antinociceptive activity of EECA, A and C in the hot plate model.

<p>Animals were pretreated with atropine (1 mg/kg, i.p.), L-NAME (3 mg/kg, i.p.), Yohimbine (1 mg/kg, i.p.) or naloxone (1 mg/kg, i.p.) 30 minutes prior to oral administration of EECA (30 mg/kg) and A or C (3 mg/kg). The results are presented as mean ± S.D. (n = 6–10) of area under the curve calculated using Prism Software 5.0. Statistical significance was calculated using ANOVA followed by Bonferroni’s test. ** < 0.005 when comparing the morphine- or the EECA, A or C-treated mice with vehicle-treated.</p

Effects of <i>C</i>. <i>limon</i>, <i>C</i>. <i>latifolia</i>, <i>C</i>. <i>limonia</i> and <i>C</i>. <i>aurantifolia</i> essential oils on the formalin-induced licking response in mice.

<p>Animals were pre-treated with oral doses of 100 mg/kg dose of each essential oil or vehicle. The results are presented as the mean ± S.D. (n = 6 per group) of the time that the animal spent licking the formalin-injected paw. Statistical significance was calculated by ANOVA followed by Bonferroni's test. *P < 0.05 when compared to vehicle-treated mice.</p

Effects of <i>C</i>. <i>limon</i>, <i>C</i>. <i>limonia</i> and <i>C</i>. <i>aurantifolia</i> essential oils on the formalin-induced licking response in mice.

<p>Animals were pre-treated with oral doses (10, 30 or 100 mg/kg) of each essential oil, acetylsalicylic acid (ASA, 100 mg/kg) or vehicle. The results are presented as the mean ± S.D. (n = 7 per group) of the time that the animal spent licking the formalin-injected paw. Statistical significance was calculated by ANOVA followed by Bonferroni's test. *P < 0.05 when compared to vehicle-treated mice.</p

Effect of limonene on formalin-induced licking and SAP models.

<p>Animals were pretreated with various doses of limonene (5.5, 16.5 or 55 mg/kg) or vehicle 1 h prior to formalin (1%) or carrageenan (1%) injection. The results are presented as the mean ± S.D. (n = 6 per group). Statistical significance was calculated by ANOVA followed by Bonferroni's test. *P < 0.05 when comparing essential oils-treated animals with carrageenan injected in the SAP with the group that received carrageenan in the SAP.</p

Anti-Inflammatory Properties and Chemical Characterization of the Essential Oils of Four <i>Citrus</i> Species

<div><p>Citrus fruits have potential health-promoting properties and their essential oils have long been used in several applications. Due to biological effects described to some citrus species in this study our objectives were to analyze and compare the phytochemical composition and evaluate the anti-inflammatory effect of essential oils (EO) obtained from four different <i>Citrus</i> species. Mice were treated with EO obtained from <i>C</i>. <i>limon</i>, <i>C</i>. <i>latifolia</i>, <i>C</i>. <i>aurantifolia</i> or <i>C</i>. <i>limonia</i> (10 to 100 mg/kg, p.o.) and their anti-inflammatory effects were evaluated in chemical induced inflammation (formalin-induced licking response) and carrageenan-induced inflammation in the subcutaneous air pouch model. A possible antinociceptive effect was evaluated in the hot plate model. Phytochemical analyses indicated the presence of geranial, limonene, γ-terpinene and others. EOs from <i>C</i>. <i>limon</i>, <i>C</i>. <i>aurantifolia</i> and <i>C</i>. <i>limonia</i> exhibited anti-inflammatory effects by reducing cell migration, cytokine production and protein extravasation induced by carrageenan. These effects were also obtained with similar amounts of pure limonene. It was also observed that <i>C</i>. <i>aurantifolia</i> induced myelotoxicity in mice. Anti-inflammatory effect of <i>C</i>. <i>limon</i> and <i>C</i>. <i>limonia</i> is probably due to their large quantities of limonene, while the myelotoxicity observed with <i>C</i>. <i>aurantifolia</i> is most likely due to the high concentration of citral. Our results indicate that these EOs from <i>C</i>. <i>limon</i>, <i>C</i>. <i>aurantifolia</i> and <i>C</i>. <i>limonia</i> have a significant anti-inflammatory effect; however, care should be taken with <i>C</i>. <i>aurantifolia</i>.</p></div

Chemical composition of peel essential oils of four <i>Citrus</i> samples.

<p>Chemical composition of peel essential oils of four <i>Citrus</i> samples.</p

Effects of <i>C</i>. <i>limon</i>, <i>C</i>. <i>aurantifolia</i> and <i>C</i>. <i>limonia</i> essential oils on carrageenan-induced IL-1β, TNF-α and IFN-γ production in a subcutaneous air pouch (SAP).

<p>Animals were pre-treated with various doses (10, 30 or 100 mg/kg, p.o.) of EO, dexamethasone (5 mg/kg, i.p.) or vehicle. The results are presented as the mean ± S.D. (n = 10 per group). Statistical significance was calculated by ANOVA followed by Bonferroni’s test. ^#<i>P</i> < 0.05 when comparing the carrageenan-injected group with the PBS-injected group and *<i>P</i> < 0.05 when comparing EO or dexamethasone-treated groups with the vehicle-treated group.</p