Overview of Parkinson's diseaseParkinson's disease is a central nervous system (CNS) disorder that causes irregular and uncontrolled body movement which are progressive in nature.
Mild tremors in upper limb are not prominently noticeable at the initial stage, but gradually the progressive nature of this disease induces uncontrolled vigorous tremor. The body becomes stiff with very slow movement in an advanced stage which hampers the quality of life of the patient.
Role of Nigella sativa in managing Parkinson's disease
There is no medication available till date to completely cure Parkinson's disease. Therefore the foremost aim of the available treatment options are:
• Slowing disease progression rate,
• Providing symptomatic relief
• Avoiding Parkinson's disease-related complication
• Improving the patient quality of life
• Developing preventive measure to avoid Parkinson's disease
Nigella Sativa can provide all the above mentioned therapeutic benefits without any serious side effects, which is more common with chemical or synthetic medications. The Nigella sativa possess multiple therapeutic properties which make this natural herbal ingredient to be a promising therapeutic agent for Parkinson's disease.
The free radicals burden increases the risk of Parkinson's disease by inducing neuronal damage. The bioactive phytochemicals like thymoquinone, carvacrol, 4-terpineol, t-anethole and essential oils are the primary constituents of Nigella sativa which act as free radical scavengers.
These phytochemicals hold potent antioxidant effect which is effective against a variety of ROS, including hydroxyl radicals (HO), superoxide radical anion (O2) and hydrogen peroxide (H2O2). These free radicals cause harmful mechanism including generation of lipid peroxidation, modification of protein structure in the body, and rupture the DNA strand. Nigella sativa supplement is effective to restrict free radical formation by increasing SOD and glutathione level in the blood serum. 
These are natural antioxidant enzymes in the body. In addition, administration of Nigella sativa supplement significantly increases the activity of quinone reductase and glutathione transferase. These two enzymes have the detoxifying ability and are effective against environmental toxins, which can cause Parkinson's disease. 
There are research studies conducted to evaluate the antioxidant property of Nigella sativa and provide satisfactory data to confirm the antioxidant property of Nigella sativa. 
The environmental toxin-induced neuronal damage can be prevented by administering Nigella sativa supplement because this herbal preparation has anti-neurodegenerative property.
A research study showed that Nigella sativa and its active constituent thymoquinone carry protective effect in brain and neuroprotective effect against chronic exposure to the environmental toxin.
Research evidence showed that Nigella sativa protects hippocampus (a region of brain structure) and prevents histopathological changes that occur due to neuronal damage. Thus, it can slow down the Parkinson's disease progression and act as a preventive measure. 
Nigella sativa and its active constituents contain specific antiparkinson property. Thymoquinone and Carvacrol are two specific phytochemicals present in Nigella sativa which have antiparkinson properties.
These two bioactive compounds reduce the oxidative stress level in the brain and prevent synthesis of lipid peroxidation and free radicals. The result of these research studies showed significant benefits of administering Nigella sativa in Parkinson's disease condition, such as:
• Increase the glutathione activity and reverse the increased level of lipid peroxidation and nitrite levels.
• Reduce muscle rigidity
• Prevents the loss of substantia nigra pars compacta neuronal activity. It also reduces the enhanced levels of malondialdehyde and that indicate a reduction of oxidative stress, as malondialdehyde acts as oxidative stress marker.
• Increase the activity of the antioxidant enzyme, including catalase.