SUL-238

The main goal of the study is to investigate how well the new drug SUL-238 works in Parkinson's Disease (PD). This is done by means of an MRS scan. An MRS scan is similar to a regular MRI scan. It will also learn about the safety of new drug SUL-238. The main questions it aims to answer are:
* Does new drug SUL-238 improve the mitochondrial function in patients with Parkinson's Disease (PD)?
* What medical problems do participants have when taking new drug SUL-238?
Researchers will compare new drug SUL-238 to a placebo (a look-alike substance that contains no drug) to see if SUL-238 works to improve mitochondrial function in patients with PD.
Participants will:
* Take new drug SUL-238 or a placebo every day for 28 days
* Visit the clinic once every 2 weeks for checkups and tests during the treatment period and finally 28 days after the last dose of SUL-238
* Keep a diary of their symptoms and the number of times they use oral new drug SUL-238