Evaluation of curcumin as add-on therapy in patients with Parkinson's disease: A pilot randomized, triple-blind, placebo-controlled trial

Preclinical studies suggest that curcumin might be a potential neuroprotective agent in Parkinson's disease (PD). This clinical trial aimed to evaluate the efficacy of adding nanomicelle curcumin on improving the motor and non-motor symptoms of PD patients and their quality of life. Idiopathic PD patients aged ≥30≥ 30 whose symptoms were under control were included in this pilot, randomized, triple-blind, placebo-controlled, add-on trial. Eligible patients were randomly assigned to either the curcumin (n = 30, 80 mg/day) or placebo (n = 30) groups and were followed for nine months. Primary outcomes were the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and Parkinson's Disease Questionnaire (PDQ-39). These variables, along with demographic data, drug history, and possible side effects of curcumin, were gathered at the beginning of the study and every three months. A mixed effects model was used to compare the group-by-time interaction, followed by post hoc analysis . Although the mean MDS-UPDRS and PDQ-39 scores were not significantly different between the curcumin and placebo groups at any time points, MDS-UPDRS part III (P = 0.04) showed a significant difference in its overall trend between the study groups. However, post hoc analysis failed to spot this difference at study time points. The most common side effects of curcumin were nausea and vomiting (P = 0.25) and gastroesophageal reflux (P = 0.42). While curcumin is a well-tolerated natural compound, this trial was unsuccessful in showing its efficacy in quality of life and clinical symptoms of PD patients. • Curcumin was not proved to be beneficial for alleviating PD symptoms. • Curcumin had no impact on PD patients' quality of life. • Changes of MDS-UPDRS part III were significantly different between the study groups. • Gastrointestinal symptoms are the most common side effects of curcumin.