Evaluation the effect of quercetin and bromelain co-supplementation (capsule of Brozyme Plus) on some inflammatory indices, oxidative stress, and clinical signs in patients with Parkinson's disease: A triple-blind randomized controlled clinical trial

To determine and compare the effects of co-supplementation of quercetin and bromelain on selected inflammatory and oxidative stress biomarkers, as well as clinical symptoms, in individuals with Parkinson’s disease before and after the intervention.

A controlled, randomized, triple-blind clinical trial with parallel groups, phase 3 on 90 patients with Parkinson's disease.

This clinical trial will be conducted in patients with Parkinson’s disease at the neurologist's clinic in Isfahan city. Participants will receive either capsules of Brozyme Plus or placebo in identical packages for 12 weeks.Participants, investigators responsible for interviews and sampling, laboratory assessors, and statisticians will remain blinded to group allocation throughout the study.

Inclusion criteria: Age of 45 years old or more; Diagnosis of Parkinson's disease based on United Kingdom PD Society Brain Bank (UKPDSBB)criteria; Having the Hoehn and Yahr score less than 5; BMI equal or less than 40; Non-inclusion criteria: Adherence to a specific diet or consumption of quercetin and bromelain supplement in the last 3 months; Take of immunosuppressive medications, or use of medications that may interact with quercetin and bromelain supplements, such as warfarin, Patients with other neurodegenerative diseases such as Huntington's disease, multiple sclerosis (MS), Wilson's disease; Central nervous system infections such as meningitis; having a Hoehn and Yahr score of 5 out of 5; History of allergy to quercetin and bromelain.

Intervention: 800 mg of quercetin and 165 mg bromelain per day, for 12 weeks. Control group: 965 mg of magnesium stearate, for 12 weeks.

Indices of inflammation and oxidative stress, disease stage, sleep quality, cognitive status, quality of life, mental health, and appetite

Participants will be allocated to the intervention and placebo groups using a stratified block randomization method with a block size of 4 and individual as the unit of randomization. For this purpose, people will be classified into 4 states based on the variables of gender and stage of the disease and people with the same states will be randomly assigned to intervention and placebo groups in a 1:1 ratio.The random sequence will be generated using a software-based random number generator provided by www.sealedenvelope.com/simple, and the allocation process will be performed by an independent researcher. In addition, allocation concealment will be ensured using opaque, sealed, and sequentially numbered envelopes containing group codes.

This study will be designed as a triple-blind randomized clinical trial. Capsules of Brozyme Plus (containing Quercetin and bromelain) and placebo will be prepared to be identical in color, shape, odor, and route of administration, and will be provided in identical packaging so that participants cannot distinguish between them, ensuring participant-level blinding. For blinding, the products will be labeled with coded identifiers A and B, and the true identity of each code will be known only to an independent researcher not involved in the trial. Participants, investigators responsible for interviews and sampling, laboratory assessors, and statisticians will remain blinded to group allocation throughout the study.