抄録
Background: Hunteria umbellata (K. Schum) is used in traditional medicine for the management of pain, diabetes mellitus. This study assessed the analgesic and antioxidant activities of aqueous extract of H. umbellata stem bark (HU) and the potential mechanism(s) of action.
Method: The antinociceptive effect of HU was evaluated using mouse writhing, tail flick, hot plate and paw licking models. To demonstrate the possible mechanism(s) of action of HU, group of animals were pretreated with naloxone (1 mg/kg, i.p), atropine (1 mg/kg, i.p), haloperidol (0.1 mg/kg, i.p), ondansetron (1 mg/kg, i.p) and phenoxybenzamine (0.1 mg/kg, i.p), 15 minutes before administration of HU. The in vivo and in vitro antioxidant potential was evaluated using established methods.
Results: The extract at 150 and 300 mg/kg, significantly (P < 0.05) reduced the number of writhing and paw licking times and increased pain threshold in hotplate test. Pretreatment of animals with ondansetron, naloxone and haloperidol, significantly (P < 0.05 and P < 0.01) attenuated the analgesic activity of HU. The extract demonstrated significant (P < 0.05) 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity with IC50 0.39 µg/ml, with high phenol content and reducing property. The total phenol content was 124.19 per gram of gallic acid. In vivo antioxidant assay showed significant (P < 0.05) increase in catalase and superoxide levels.
Conclusion: Results from this study suggests the involvement of serotonergic, opioidergic and dopaminergic pathways in the analgesic effect of H. umbellata stem bark. The potent antioxidant potential may have also contributed to the analgesic effect of HU.
