Background: Parkinson's disease (PD) ranks as the second most common neurodegenerative disorder, primarily impacting the elderly population. It is caused by degeneration of dopaminergic neurons in the striatum. Sinomenine (SN) has been shown todecrease the production of pro-inflammatory mediators, such as intracellular ROS, TNF-alpha, NO, and PGE2 thereby reducing neuroinflammation. Thus, the study was designed to assess the neuroprotective effect of SN in the rotenone-induced PD of Drosophilamelanogaster. Materials and Method: Drosophila flies were cultured in cornmeal agar medium. Seven-day-old flies were divided into five groups (n=30): normal control, disease control, Levodopa (1 mM), and SN low (0.125%) and high dose (0.25%). Rotenone (125 µM) was used to induce the disease. All drugs were administered through the cornmeal agar medium for seven days, and on the eighth day, a climbing assay was performed. Effect on biochemical variables like Malondialdehyde (MDA) and Dopamine levels in the Drosophila brain were also assessed. Result: There was a significant improvement in the flying and climbing ability of Drosophila flies in the SN (high and low doses) and L-dopa groups compared to the disease control group. Also, there was a significant increase in levels of Dopamine and a decrease in levels of MDA in the Drosophila brain in the SN-treated groups and the L-dopa group. All these effects were most pronounced in the group receiving a high dose of SN. Conclusion: Sinomenine was found to be neuroprotective as it improved the locomotor activity of Drosophila flies. It acts by preventing the degeneration of dopaminergic neurons, probably by reducing oxidative stress.

Dopamine, Malondialdehyde, Levodopa, Rotenone, Climbing assay