Silymarin consists of a mixture of plant compounds known as flavonolignans. This extract can be isolated from milk thistle (Silybum marianum), a flowering plant native to Mediterranean countries and widely used in traditional medicine. According to studies, silymarin possesses liver-protective, antioxidant, anti-inflammatory, anti-cancer, and cardioprotective properties. (Related: Silymarin is one of the best ways to support liver health.)
The three main components of silymarin are silybin or silibinin, silidianin, and silicristin. The most active of the three is the flavonoid silibinin, which is said to be responsible for silymarin's various biological activities. Some of the well-known health benefits associated with silymarin include:
In their study, South Korean researchers demonstrated the potential of silibinin as an alternative treatment for Parkinson's disease and Alzheimer's disease. While Parkinson's mainly affects motor functions, it can also impair memory and other cognitive functions like Alzheimer's. Both conditions are considered neurodegenerative diseases that primarily affect neurons in the brain.
Parkinson's disease and Alzheimer's disease exhibit common features that are caused by numerous factors. One common feature of both diseases is neurotoxic inflammation. This type of inflammation is caused by the activation of microglia -- the resident immune cells in the brain and spinal cord. Because of this, the regulation of microglial activation is considered a potential mechanism for preserving neurons in the brains of patients with Alzheimer's or Parkinson's.
In their previous study, the researchers reported that the upregulation of prothrombin kringle-2 (pKr-2), a protein domain associated with the initiation and progression of Parkinson's disease, can induce microglial activation. This microglial activation leads to the death of dopaminergic neurons located in the substantia nigra, the part of the brain responsible for sending signals down the spinal cord to control the muscles of the body.
To determine if silibinin can prevent this, the researchers treated the substantia nigra of mice with the flavonoid and pKr-2. They reported that silibinin suppressed the production of inducible nitric oxide synthase (iNOS) -- an enzyme involved in inflammation and cell death (apoptosis) -- and neurotoxic inflammatory cell-signaling molecules like interleukin-1B and tumor necrosis factor-a (TNF-a). This inhibition occurred through the downregulation of an important signaling pathway that controls cell function.
After performing several tests to evaluate the activity of silibinin in vivo, the researchers reported that silibinin treatment could protect neurons in the substantia nigra from pKr-2-triggered neurotoxic inflammation.
Based on these results, the researchers concluded that silibinin is a beneficial natural compound with anti-inflammatory effects that can reverse pKr-2-triggered neurotoxicity. They believe that it can be used to protect dopaminergic neurons in the brain and treat Parkinson's disease.