Mucuna pruriens (mucuna) seeds contain 3-6% L-DOPA, and have been used in traditional Ayurvedic medicine to treat diseases resembling Parkinson’s disease (PD). Pilot studies in PD show that mucuna seed powder has similar effects to conventional levodopa/carbidopa medication. Formulations of mucuna seed are readily available through the internet, and are used by some PD patients as an alternative to conventional levadopa/carbidopa medication. The purpose of this study was to examine the L-DOPA content of a range of popular mucuna products in order to assess the veracity of label claims.
Six different brands of mucuna product were ordered through the internet. Certificates of analysis were obtained where possible. A standard amount of each product was extracted using methanol: formic acid for analysis using reversed-phase high performance liquid chromatography (HPLC) with ultraviolet and fluorescence detection. L-DOPA content was calculated using a standard curve prepared using L-DOPA (Sigma-Aldrich) as reference.
The claimed L-DOPA content ranged from 25 to 250mg per dose for the six products. HPLC analysis revealed that only two of the products had L-DOPA values close to the value claimed. The remaining products contained considerably less L-DOPA , <10% in two cases, than implied on the label. Certificates of analysis suggested that not all manufacturers routinely measure L-DOPA content of their mucuna product.
Four of six products examined showed a large discrepancy between label claim and L-DOPA content, independently measured by HPLC. This finding warrants further investigation as these deficiencies could impact both patients, and the outcome of clinical studies using these products.