Objective Mucuna pruriens (MP) is a legume whose seeds contain levodopa (LD), which has potential therapeutic effects against Parkinson's disease (PD). However, further research is needed to thoroughly evaluate its efficacy and safety for treating this condition. In this study, we analyzed the pharmacokinetics of MP grown in Japan and investigated its mechanism of action in PD. Methods MP seeds ground after roasting (containing 4.02% LD per MP powder) were used as the reagent and compared with an equivalent LD/carbidopa (CD) preparation. This clinical trial was conducted using a crossover design among PD patients attending our institution. Each patient received a single dose of 100/10 mg LD/CD tablets and 11 g of MP reagent. Results Among the seven patients with PD, MP prolonged the ON time 2-fold compared to LD/CD. The LD concentrations after MP intake were higher than those after LD/CD intake, whereas dyskinesia did not increase. An analysis of the LD metabolites showed that the 3-O-methyl-dopa/LD metabolic ratio was significantly lower after MP ingestion than after LD/CD ingestion, indicating that MP has a catechol-O-methyl transferase inhibitory effect. Conclusions This is the first report of a pharmacokinetic analysis conducted on actual patients with PD showing that MP significantly prolongs the ON time. The advantages of MP as a treatment for PD have been confirmed: it is inexpensive, as effective as LD, works faster and longer than LD, and does not increase dyskinesia.
Keywords: COMT inhibition; Mucuna pruriens; Parkinson's disease; dyskinesia; levodopa.