Background: Parkinson’s disease (PD) is associated with progressive neuronal damage and dysfunction. Oxidative stress helps to regulate neurodegenerative and neuronal dysfunction. Natural compounds could attenuate oxidative stress in a variety of neurological disorders. B. juncea is a rich source of antioxidants. The present study aimed to evaluate the therapeutic potential of B. juncea leaves for the treatment of PD by applying behavioral, in vivo and in silico studies. For in vivo studies rats were divided into six groups (n = 6). Group-I served as normal control (vehicle control). Group-II was disease control (haloperidol 1 mg/kg). Group-III was kept as a standard group (L-Dopa 100 mg/kg + carbidopa 25 mg/kg). Groups (IV–VI) were the treatment groups, receiving extract at 200-, 400- and 600 mg/kg doses respectively, for 21 days orally. Results: In vivo study results showed that the extract was found to improve muscles strength, motor coordination, and balance in PD. These behavioral outcomes were consistent with the recovery of endogenous antioxidant defence in biochemical analysis which was further corroborated with histopathological ameliorations. Dopamine levels increased and monoamine oxidase B (MAO-B) levels decreased dose-dependently in the brain during the study. Herein, we performed molecular docking analysis of the proposed extracted phytochemicals has explained that four putative phytochemicals (sinapic acid, rutin, ferulic acid, and caffeic acid) have presented very good results in terms of protein-ligand binding interactions as well as absorption, distribution, metabolism, excretion & toxicity (ADMET) profile estimations. Conclusion: The undertaken study concluded the anti-Parkinson activity of B. juncea and further suggests developments on its isolated compounds in PD therapeutics.