The Roles of Flavonols/Flavonoids in Neurodegeneration and Neuroinflammation

Abstract

Inflammatory process in the human body is a physiological response involving many cellular types and mediators. It results in scar formation to separate the damaged area from the surrounding healthy tissue. Because of increased blood-brain barrier permeability following inflammation, leukocytes infiltrate the CNS and are also supplemented by proinflammatory mediators. However, an acute inflammatory process after cerebral trauma or stroke may also result in a prolonged lesion formation, leading to a severe neuronal loss. Prolonged inflammatory process in the CNS may cause serious damage to the neuronal system. It may lead to CNS damage in such a way that endangers functional integration and proinflammatory system balance. Effects of different flavonoid species on ischemia-reperfusion injury and cognition and function have also been shown in experimental studies. Flavonoids are presented broadly in plants and diets. They are believed to have various bioactive effects including anti-viral, anti-inflammatory, cardioprotective, anti-diabetic, anti-cancer, anti-aging, etc. Quercetine is the predominant dietary flavonoid. Main sources are tea, onion, and apple. It is demonstrated that frequently consumed food like soybean, peanut, mustard, rice, sesame, olive, potatoes, onion, and oats contain flavonoids. Catechin and its derivates which are isolated from tea leaves have antioxidant activity but in low doses, their prooxidant effects are also reported. Ipriflavone which is a synthetic flavonoid may increase total calcium in bone. In this review, the effects of flavonoids species on the inflammatory process in the neurodegenerative process were examined as general.

Targeting Oxidative Stress and Inflammation to Prevent Ischemia-Reperfusion Injury

“…The protective effect of resveratrol on CIRI in mice is also related to its antioxidant properties (Dou et al, 2019). Flavonoids, presented broadly in plants and diets, have also been shown the effect and function on CIRI and cognition in experimental studies on their different flavonoid species, such as quercetine and catechin (Calis et al, 2019).…”

Tea Consumption Is Associated with Decreased Disease Activity of Rheumatoid Arthritis in a Real-World, Large-Scale Study

“…A recent study showed that EGCG-mediated inhibition of G3BP1 provided a potential treatment for cGAS-related autoimmune diseases [26]. Overall, tea polyphenols provide a variety of biological actions such as anti-oxidant, anti-carcinogenic, anti-viral and anti-microbial activities [27][28][29]. High-intake of tea implies a higher uptake of tea polyphenols containing EGCG, which can result in a more obvious anti-inflammatory effect.…”

“…One of the possible explanations for the negative association between jasmine tea and disease severity could be that the jasmine tea is made of a mixture of tea leaves and jasmine blossoms [30]. The polyphenols of tea leaves, which are found in all 3 kinds of tea, have showed anti-inflammatory effects in many studies [28]. Notably, some studies have reported that jasmine flowers also have therapeutic effects on inflammatory diseases, such as conjunctivitis and dermatitis [31].…”

The Role of Natural Compounds and their Nanocarriers in the Treatment of CNS Inflammation

“…Flavonoids are the most common natural compounds in plants, vegetables, fruits, and dietary foods. Flavonoids can exhibit antioxidant effects by inhibiting ROS production, anti-inflammatory effects by modulating various signaling pathways, and antiapoptotic effects by inhibiting proapoptotic molecules as well as angiogenic effects [ 58 , 59 ]. Apigenin, 4′,5,7-trihydroxyflavone, is a major constituent of chamomile herbs and can be synthesized from naringenin [ 60 ].…”