RESUMO
CONTEXT: Hypericum perforatum Linn. (Hypericaceae) (St. John's wort) attenuates opium withdrawal signs. AIM: To explore the therapeutic potential of Hypericum perforatum in the management of opium-induced withdrawal syndrome. MATERIALS AND METHODS: The effect of the Hypericum perforatum hydro-ethanol extract was investigated for potential to reverse naloxone (0.25 mg/kg)-induced opium withdrawal physical signs. Rats received opium extract (80-650 mg/kg) twice daily for 8 days along with Hypericum perforatum (20 mg/kg, orally) twice daily in chronic treatment and the same single dose 1 h before induction of withdrawal syndrome in the acute treated group. RESULTS: Hypericum perforatum reduced stereotype jumps and wet dog shake number in the chronic treatment compared to the saline control group (F(2, 24) = 3.968, p < 0. 05) and (F(2, 24) = 3.689, p < 0.05), respectively. The plant extract in the acutely treated group reduced diarrhea (F(2, 24) = 4.850, p < 0. 05 vs. saline). It decreased rectal temperature by chronic treatment at 30 min (F(2, 24) = 4.88, p < 0.05), 60 min (F(2, 240 = 5.364, p < 0.01) and 120 min (F(2, 24) = 4.907, p < 0.05). DISCUSSION AND CONCLUSION: This study reveals that the extract of Hypericum perforatum attenuates some physical signs of opium withdrawal syndrome possibly through direct or indirect interaction with opioid receptors. Further study is needed to clarify its mechanism.