Malva sylvestris aqueous extract could ameliorate 6-hydroxydopamine-induced motor asymmetry with no protective effect on dopaminergic nigrostriatal neurons in the rat

Background and Objective: Parkinson’s disease (PD) is a common neurological disorder due to degeneration of dopaminergic neurons within pars compacta of substantia nigra (SNC). With regard to protective effect of Malva sylvestris (MS), this study was conducted to evaluate the effect of aquaeous extract of this plant in an experimental model of PD induced by 6-hydroxydopamine (6-OHDA). Materials and Methods: Rats were divided into sham-operated, MS-treated sham-operated, lesioned and MS-treated lesioned groups. The hemi-PD early model was induced by unilateral intrastriatal injection of 6-OHDA (12.5 µg/5µl of saline-ascorbate, left side). The treated groups received aquaeous extract of MS (i.p.) at a dose of 100 mg/kg once a day for one week at an interval of 24 h till 1 h pre-surgery. One week after surgery, the animals were tested for rotational behavior by apomorphine for an hour and the number of dopaminergic neurons in the SNC was counted. Results: After one week, apomorphine caused a significant contralateral turning (P < 0.001) in 6-OHDA-lesioned group and a reduction in the number of neurons on the left side of the SNC in the lesioned group (P < 0.05) in comparison with sham group. In addition, pretreatment with MS extract at a dose of 100 mg/kg significantly decreased the rotational behavior in lesioned rats (p < 0.01) but could not significantly prevent the reduction of SNC neurons versus lesioned group. Conclusion: Intraperitoneal administration of aquaeous extract of Malva sylvestris could reduce motor asymmetry and has not neuroprotective effect against 6-OHDA toxicity in an experimental model of PD.