Development and Validation of a Reversed-Phase HPLC Method with UV Detection for the Determination of L-Dopa in <i>Vicia faba</i> L. Broad Beans

• Published in: Molecules
• Main Authors: Carmen Tesoro, Rosanna Ciriello, Filomena Lelario, Angela Di Capua, Raffaella Pascale, Giuliana Bianco, Mario Dell’Agli, Stefano Piazza, Antonio Guerrieri, Laura Scrano, Sabino A. Bufo, Maria Assunta Acquavia
• Format: Article
• Language: English
• Published: MDPI AG 2022-11-01
• Subjects: drugs; bioactive compound; liquid chromatography; UV detection; broad beans; aqueous stability
• Online Access: https://www.mdpi.com/1420-3049/27/21/7468

L-Dopa (LD), a substance used medically in the treatment of Parkinson’s disease, is found in several natural products, such as <i>Vicia faba</i> L., also known as broad beans. Due to its low chemical stability, LD analysis in plant matrices requires an appropriate optimization of the chosen analytical method to obtain reliable results. This work proposes an HPLC-UV method, validated according to EURACHEM guidelines as regards linearity, limits of detection and quantification, precision, accuracy, and matrix effect. The LD extraction was studied by evaluating its aqueous stability over 3 months. The best chromatographic conditions were found by systematically testing several C₁₈ stationary phases and acidic mobile phases. In addition, the assessment of the best storage treatment of <i>Vicia faba</i> L. broad beans able to preserve a high LD content was performed. The best LD determination conditions include sun-drying storage, extraction in HCl 0.1 M, chromatographic separation with a Discovery C₁₈ column, 250 × 4.6 mm, 5 µm particle size, and 99% formic acid 0.2% <i>v</i>/<i>v</i> and 1% methanol as the mobile phase. The optimized method proposed here overcomes the problems linked to LD stability and separation, thus contributing to the improvement of its analytical determination.