Effects of the ethanolic extract of passiflora foetida on morphine addiction in mice and rats

Abstract

Passiflora foetida, (Ka-tok-rok, Passifloraceae) has been used for the treatments of cough, fever, pain, head-ache, and also used as an expectorant and diuretic in Thai traditional medicine. Since P. incarnata has been proved to be useful in drug addiction therapy, therefore we were interested to investigate the effect of P. foetida, a plant in the same genus Passiflora, on morphine addiction. We initially evaluated the effect of the ethanolic extract of P. foetida (PF) on locomotor activity in mice. The results showed that all doses of PF (25, 50, 100 and 200 mg/kg, p.o.) produced no significant effects on locomotor activity. The reinforcing effect of PF and the effect of PF on morphine-induced conditioned place preference (CPP) were investigated using CPP paradigm in rats. All doses of PF did not show any significant effects on CPP but could suppress morphine-induced CPP. We then assessed the effects of PF on morphine withdrawal in mice. Pretreatment with of all doses of PF and methadone (1 mg/kg, i.p.) prior to morphine injection significantly (p<0.05) decreased naloxone-precipitated withdrawal jumping and straub tail behaviors compared to vehicle controls. All doses of PF tested except the lowest dose significantly (p<0.05) decreased naloxone-precipitated withdrawal jumping behavior in morphine dependence when compared to vehicle controls similar to methadone (1 mg/kg, i.p.). Additionally, all doses of PF also significantly (p<0.05) reduced withdrawal straub tail behavior and PF at the doses of 25 and 50 mg/kg significantly (p<0.05) reduced withdrawal wet dog shake behavior when compared to vehicle controls. In conclusions, the present study demonstrated that PF did not have neither stimulating nor sedative effects, PF did not have reinforcing effect by itself but it could suppress the reinforcing effect of morphine. Moreover, PF may have prevention and treatment effects on morphine withdrawal. These results indicated that PF may have a potential to be developed for the treatment of opioid addiction. However, the active chemical constituents in PF and mechanisms of PF action may need to be further investigated.