<![CDATA[Introduction: Accumulating research supports the view that oxidative stress is a key driver of the pathological processes underlying Parkinson’s disease (PD). Among biomarkers of oxidative injury, malondialdehyde (MDA)—a key lipid peroxidation product—is frequently utilized to quantify oxidative stress; however, its relationship with motor symptom severity and cognitive function in PD remains insufficiently explored. This study aimed to examine the association between serum MDA levels, motor symptom severity, and cognitive function in patients with Parkinson’s disease. Methods: This cross-sectional study included 35 patients diagnosed with PD. Motor severity was assessed using the Unified Parkinson’s Disease Rating Scale Part III (UPDRS-III) and stratified into mild, moderate, and severe levels. Cognitive assessment utilized the Montreal Cognitive Assessment–Indonesia (MoCA-Ina) alongside trail making test part A (TMT-A) and trail making test part B (TMT-B). Serum MDA concentrations were measured using the thiobarbituric acid reactive substances (TBARS) assay. Statistical assessment was conducted using Spearman’s rank correlation alongside the Mann–Whitney U test. Results: This study revealed a meaningful positive linkage between MDA concentrations and motor symptom severity (r = 0.421, p = 0.012). Posthoc analysis indicated that patients with moderate and severe motor symptoms had higher MDA levels than those with mild symptoms (p = 0.032; p = 0.022), while no discrepancy was found between the moderate and severe groups (p = 0.421). MDA levels showed no significant association with MoCA-Ina or TMT-A performance (r = 0.206, p = 0.235; r = 0.079, p = 0.684), but patients with abnormal TMT-B performance had higher MDA levels than participants with normal results (p = 0.043). Conclusion: MDA level is linked to greater motor symptom severity and executive dysfunction in PD. The results imply that MDA may act as a promising biomarker reflecting oxidative damage–driven neurodegeneration underlying motor and executive impairments in PD.]]>
