Assessment of anti-dyskinetic efficacy of alkaloids of mucuna pruriens seed extract in rodent model of Parkinson's disease

Mucuna pruriens (MP) has long been used in Indian ayurvedic medicine as support in the treatment of Parkinson's disease (PD). In a previous preclinical study of our research group we did an extensive evaluation of the antiparkinsonian effects of the extract of MP seeds known to contain, among other components, 12.5% L-DOPA, as compared to equivalent doses of L-DOPA. In particular, the effects of MP extract were investigated by means of the turning behaviour test and in the induction of abnormal involuntary movements (AIMs) after sub-chronic administration in unilateral 6-hydroxydopamine-lesioned rats. During sub-chronic administration, both MP extract (48 mg/kg) and L-DOPA (6 mg/kg) induced sensitization of contralateral turning behaviour; however, MP extract induced AIMs of lower intensity respect to L-DOPA. Thus, in order to evaluate which alkaloid component of MP extract might have anti-dyskinetic potential and be responsible of the low dyskinetic potential of the MP extract, it was evaluated the effect of a sub-chronic treatment with 1) L-DOPA (6 mg/kg); 2) alkaloid A of MP extract plus L-DOPA (6 mg/kg) and 3) alkaloid B of MP extract plus L-DOPA (6 mg/kg). During the treatment contralateral turning behaviour and AIMs were analysed. Sub-chronic treatment with alkaloid A of MP extract plus L-DOPA (6 mg/kg) showed a strong reduction of axial AIMs induced by L-DOPA, whereas sub-chronic treatment with alkaloid B of MP extract plus L-DOPA (6 mg/kg) showed only a low reduction of axial AIMs induced by L-DOPA. Conversely both alkaloids did not seem have any effects on limb AIMs and on sensitization of turning behaviour induced by L-DOPA.These findings suggest that alkaloid A of MP extract might have a partial anti-dyskinetic activity in PD model.