Mucuna pruriens (Velvet bean) Rescues Motor, Olfactory, Mitochondrial and Synaptic Impairment in PINK1(B9) Drosophila melanogaster Genetic Model of Parkinson’s Disease

The fruit fly Drosophila melanogaster (Dm) mutant for PTEN-induced putative kinase 1 (PINK1(B9)) gene is a powerful tool to investigate physiopathology of Parkinson's disease (PD). Using PINK1(B9) mutant Dm we sought to explore the effects of Mucuna pruriens methanolic extract (Mpe), a L-Dopa-containing herbal remedy of PD. The effects of Mpe on PINK1(B9) mutants, supplied with standard diet to larvae and adults, were assayed on 3–6 (I), 10–15 (II) and 20–25 (III) days old flies. Mpe 0.1% significantly extended lifespan of PINK1(B9) and fully rescued olfactory response to 1-hexanol and improved climbing behavior of PINK1(B9) of all ages; in contrast, L-Dopa (0.01%, percentage at which it is present in Mpe 0.1%) ameliorated climbing of only PINK1(B9) flies of age step II. Transmission electron microscopy analysis of antennal lobes and thoracic ganglia of PINK1(B9) revealed that Mpe restored to wild type (WT) levels both T-bars and damaged mitochondria. Western blot analysis of whole brain showed that Mpe, but not L-Dopa on its own, restored bruchpilot (BRP) and tyrosine hydroxylase (TH) expression to age-matched WT control levels. These results highlight multiple sites of action of Mpe, suggesting that its effects cannot only depend upon its L-Dopa content and support the clinical observation of Mpe as an effective medication with intrinsic ability of delaying the onset of chronic L-Dopa-induced long-term motor complications. Overall, this study strengthens the relevance of using PINK1(B9) Dm as a translational model to study the properties of Mucuna pruriens for PD treatment.