In the present study, the rhizome essential oil from Zingiber zerumbet (Zingiberaceae) was evaluated for antinociceptive activity using chemical and thermal models of nociception, namely, the acetic acid-induced abdominal writhing test, the hot-plate test and the formalin-induced paw licking test. It was demonstrated that intraperitoneal administration of the essential oil of Z. zerumbet (EOZZ) at the doses of 30, 100 and 300 mg/kg produced significant dose-dependent inhibition of acetic acid-induced abdominal writhing, comparable to that of obtained with acetylsalicylic acid (100 mg/kg). At the same doses, the EOZZ produced significant dose-dependent increases in the latency time in the hot-plate test with respect to controls, and in the formalin-induced paw licking test, the EOZZ also significantly reduced the painful stimulus in both neurogenic and inflammatory phase of the test. In addition, the antinociceptive effect of the EOZZ in the formalin-induced paw licking test as well as hot-plate test was reversed by the nonselective opioid receptor antagonist, naloxone suggesting that the opioid system was involved in its analgesic mechanism of action. On the basis of these data, we concluded that the EOZZ possessed both central and peripheral antinociceptive activities which justifying its popular folkloric use to relieve some pain conditions.

Objectives: To determine the anti-inflammatory and antinociceptive activities of Mitragyna speciosa Korth methanol extract in rodents. Materials and Methods: Anti-inflammatory activity was evaluated using carrageenan-induced paw edema and cotton pellet-induced granuloma tests in rats. Antinociceptive activity was measured using the writhing test and the hot plate test in mice, and the formalin test in rats. All drugs and extracts were diluted in dH2O and administered through the intraperitoneal route. Results were analyzed using one-way ANOVA followed by Dunnett’s test for multiple comparisons among groups. Results: Results showed that intraperitoneal administration of the extract at doses of 100 and 200 mg/kg produced significant dose-dependent activity in all of the nociceptive models evaluated (p < 0.05). With the formalin test, the antinociceptive activity in mice was inhibited only at the highest dose of the extract (200 mg/kg). The study also showed that intraperitoneal administration of the methanol extract of M. speciosa (100 and 200 mg/kg) significantly and dose-dependently suppressed the development of carrageenan-induced rat paw edema (p < 0.05). In the chronic test, however, significant reduction in granulomatous tissue formation in rats was observed only at the highest dose of the methanol extract of M. speciosa (200 mg/kg, p < 0.05). Conclusion: The present study suggests the presence of potent antinociceptive and anti-inflammatory principles in the extract, supporting its folkloric use for the treatment of these conditions.

Moringa oleifera L. (Moringaceae) is known to possess high nutritional value and is used in a folklore medicine to treat various ailments related to pain and inflammation. The aim of the present study was to evaluate the antinociceptive and anti-inflammatory effects of the aqueous extract of the leaves of M. oleifera in laboratory animals, using the writhing, hot-plate and formalin tests as the antinociceptive assays, and carrageenan-induced paw edema test as the anti-inflammatory assay. The extract (10, 30 and 100 mg/kg) exhibited significant (P < 0.05) antinociceptive activity, which occurred in a dose-dependent manner, in all tests used. The extract also exhibited significant (P < 0.05) anti-inflammatory activity in a dose-dependent manner. Furthermore, the extract antinociceptive activity was suggested to be modulated via opioid receptors at the central, but not peripheral, antinociceptive level, based on the ability of 5 mg/kg naloxone to reverse the extract activity in the hot-plate, but not the writhing test. In conclusion, M. oleifera leaves possess peripherally non-opioid mediated and centrally opioid mediated antinociceptive and anti-inflammatory activities. This study also confirms the traditional uses of M. oleifera in the treatment of ailments, particularly those related to pain and inflammation.