Mansoa alliacea extract presents antinociceptive effect in a chronic inflammatory pain model in mice through opioid mechanisms.

In some chronic disorders, as in arthritis, the inflammatory pain persists beyond the inflammation control becoming pathological. Its treatment shows limited efficacy and adverse effects which compromises patients' quality of life. Mansoa alliacea, known as 'cipo alho', is popularly used as analgesic and others species of this genus show anti-inflammatory actions. We investigated the anti-inflammatory and antinociceptive potential of M. alliacea extract in an inflammatory pain model which presents inflammatory characteristics similar to those caused by arthritis, through of the intraplantar injection of complete Freund's adjuvant (CFA) in mice. The extract chromatographic analysis revealed the presence of ρ-coumaric, ferulic and chlorogenic acids, luteolin, and apigenin. The treatment with M. alliacea prevented and reversed the CFA-induced mechanical allodynia with maximum inhibition (Imax) of 100% and 90 ±â€¯10%, respectively. The co-administration of M. alliacea extract plus morphine enhanced the anti-allodynic effect with Imax of 100%. The M. alliacea extract also reverted the CFA-induced thermal hyperalgesia with Imax of 3.6 times greater compared to the vehicle and reduced the thermal threshold under physiological conditions. However, M. alliacea extract did not reduce the CFA-induced edema and myeloperoxidase activity. Additionally, non-selective and δ-selective opioid receptor antagonists, but not κ-opioid, prevented extract anti-allodynic effect with Imax of 98 ±â€¯2% and 93 ±â€¯2%, respectively. Moreover, M. alliacea extract did not induce adverse effects commonly caused by opioids and other analgesic drugs, at least in the tested pharmacological doses after the acute treatment. M. alliacea extract presents antinociceptive activity in an inflammatory pain model, which presents inflammatory characteristics similar to those arthritis-induced, without causing adverse effects in tested pharmacological doses. These effects seem to be mediated mainly via δ-opioid receptors.

Antinociceptive and antidepressant-like effects of the crude extract of Vitex megapotamica in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Vitex megapotamica (Spreng) Moldenke has been used in South American folk medicine to treat inflammatory diseases. However, the effects of V. megapotamica on animal models of nociception and depression have not been evaluated. AIM OF THE STUDY: This study investigated whether the crude leaf extract of V. megapotamica exhibits antinociceptive and antidepressant-like effects in a Freund's adjuvant-induced chronic inflammation and depression model. MATERIALS AND METHODS: Chronic inflammation was induced in rats by the intraplantar administration of complete Freund's adjuvant (CFA; 100µl). The effect of oral crude extract of V. megapotamica (VmE; 3-30mg/kg, p.o.) on nociception (thermal hyperalgesia, mechanical allodynia and arthritis score), inflammation (edema, myeloperoxidase activity), immobility (forced swimming test), locomotor activity (open field), gastrointestinal transit, hyperalgesia and naloxone-precipitated morphine withdrawal syndrome was evaluated. Naloxone (0.4mg/kg, i.p.) was used to investigate the involvement of opioid system in the currently described effects of VmE. RESULTS: Crude extract caused antinociceptive/antidepressant-like effects in the CFA-induced chronic inflammation model, which was prevented by naloxone. The VmE extract (10mg/kg, p.o.) did not alter the locomotor activity, gastrointestinal function and inflammatory parameters and did not cause hyperalgesia. CONCLUSION: V. megapotamica induces opioid-dependent antinociception and antidepressant-like effect, without anti-inflammatory activity. The results support the use of VmE as analgesic and antidepressant.