Elmira Barari Paeen-Lamouki - Nutrition student at the Department of Nutrition, Faculty of Medicine, Research & Sciences Branch, Islamic Azad University
Sarah Sarafizadeh - Assisstant professor at the Department of Nutrition, Faculty of Medicine, Research & Sciences Branch, Islamic Azad University

The role of plants in maintaining health and preventing diseases is clear and it is dare to say that flavonoids could be considered the most famous one. Despite the popular belief about the effectiveness of flavonoid on oxidative stress, especially in the prevention of diseases such as cancer, the efficiency of flavonoids and its possible mechanism is unclear. Quercetin is categorized as a Flavonol, one of the six subclasses of flavonoid compounds. Different studies have shown dissimilar opinions, and yet an uncertainty loom has covered the role of quercetin on many diseases. The present study has attempted to explore the extraordinary role of quercetin in treatment of diseases.Methods: This study was a library based by using the published articles in scientific databases like, PubMed and SID since 1995 until 2015.Results: According to existing studies, long-term feeding of quercetin (20 mg/day) could increase serum and liver alpha-tocopherol concentrations and significantly decrease Malondialdehyde concentrations. In addition, quercetin effects on allergy, asthma, and atopic disease. In murine models of allergic airway inflammation and asthma, quercetin had pronounced anti-inflammatory effects and inhibited asthmatic reactions. Furthermore, this substance has a variety of anticancer mechanisms, including antioxidant, anti-proliferative, pro-apoptotic, and cell signaling effects, and growth factor suppression, as well as potential synergism with some chemotherapeutic agents. Quercetin effects on diabetes by its inhibitory function of lens aldose reductase-the enzyme that catalyzes the conversion of glucose to sorbitol-that is especially important in the eye and plays an essential role in the formation of diabetic cataracts. Quercetin supplementation attenuates the development of cardiac hypertrophy induced by overloaded pressure. Finally, quercetin has gastro protective and oral mucosa effect and had benefits on immunity, infections, inflammation, injury, pain, prostatitis, arthritis, metabolic syndrome, obesity, mood disorders and sleep.Conclusion: Due to the important role of quercetin in prevention and treatment of diseases, a daily dietary fruit, vegetables, seeds and nuts to supply quercetin is recommended.

Quercetin, Flavonoid, Diseases