Zembrin® Mitigates Reserpine-Induced Motor Dysfunction and Oxidative Stress in Parkinson’s Disease: In Vivo and In Silico Analyses

Parkinson’s disease (PD), impacting millions worldwide, leads to motor deficits and various non-motor symptoms. Although there is no cure, treatment primarily involves dopamine replacement therapy, especially L-dopa for motor symptoms, and additional drugs are required to address non-motor effects. This underscores the increasing demand for dual-acting drugs that can effectively target both symptom types in PD. This study explored the potential effects of a standardised Mesembryanthemum tortuosum extract, Zembrin®, in treating PD, utilising in vivo and in silico models. Zebrafish larvae were subjected to pre-treatment with reserpine, followed by exposure to Zembrin®, with selegiline and L-dopa as positive controls. The in vivo component of this study monitored locomotion and oxidative stress, while the in silico component identified potential drug targets for the treatment of PD. Reserpine induced hypolocomotion and oxidative stress in zebrafish larvae, and Zembrin® (12.5 µg/mL) effectively enhanced locomotion and reduced oxidative stress. The molecular docking, molecular dynamics simulations, and binding free energy calculations revealed that four mesembrine alkaloids (mesembranol, mesembrenol, mesembrenone, and mesembrine) form stable and energetically favourable complexes with monoamine oxidase B (MAO-B) and dopamine transporter (DAT), which are significant targets for addressing both the motor and non-motor effects of PD.