Quercetin, a naturally occurring flavonoid abundant in fruits, vegetables, herbs and plant-based foods, is renowned for its diverse biological activities and wide-ranging applications across multiple fields. As a key bioactive compound, it has drawn extensive attention from researchers, healthcare professionals and industry practitioners for its potential health benefits and functional value.
Core Biological Benefits of Quercetin
1. Powerful Antioxidant ActivityQuercetin acts as a potent free radical scavenger, effectively neutralizing reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the body. It enhances the activity of endogenous antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), inhibits lipid peroxidation of cell membranes, and protects cells and tissues from oxidative damage, thus delaying oxidative aging and reducing the risk of oxidative stress-related diseases.
2. Anti-inflammatory Effects
It exerts anti-inflammatory effects by modulating key inflammatory signaling pathways, including the NF-κB pathway. Quercetin inhibits the production and release of pro-inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), stabilizes mast cell membranes and suppresses histamine release, thereby alleviating acute and chronic inflammatory responses in the body and relieving symptoms of inflammatory diseases.
3. Cardioprotective Properties
Quercetin improves vascular endothelial function and promotes the bioavailability of nitric oxide (NO), a key molecule for vasodilation. It inhibits angiotensin-converting enzyme (ACE) activity, helping to lower blood pressure, and reduces lipid peroxidation in blood vessels, preventing the oxidation of low-density lipoprotein (LDL). These effects collectively protect the cardiovascular system, reducing the risk of hypertension, atherosclerosis and other cardiovascular diseases.
4. Immunomodulatory Function
It regulates the body’s immune response by balancing the activity of immune cells such as T lymphocytes, B lymphocytes and macrophages. Quercetin enhances the body’s innate immune defense while inhibiting excessive immune reactions, making it beneficial for maintaining immune homeostasis and improving resistance to pathogens.
5. Metabolic Regulation
Quercetin inhibits the activity of α-glucosidase, an enzyme that breaks down carbohydrates, slowing down glucose absorption and helping to regulate blood glucose levels. It also improves insulin sensitivity in peripheral tissues, promoting glucose utilization by cells. Additionally, it can regulate lipid metabolism, reducing triglyceride and LDL levels, supporting metabolic health.
6. Skin Protective Effects
Its antioxidant and anti-inflammatory properties extend to skin health: it scavenges free radicals induced by ultraviolet (UV) radiation, reducing photoaging; alleviates inflammatory reactions in acne-prone skin; and helps repair the skin barrier, improving skin hydration and resilience.
Key Application Areas
1. Nutraceuticals and Dietary Supplements
As a popular natural bioactive ingredient, quercetin is widely formulated into dietary supplements (in forms of capsules, tablets, powders and liquid extracts). These products are marketed for antioxidant support, immune enhancement, cardiovascular health maintenance and metabolic regulation, catering to the growing demand for natural health products among consumers.
2. Pharmaceutical Research and Development
Quercetin is a promising candidate for novel drug development due to its diverse therapeutic effects. Researchers are exploring its potential as an adjunct therapy for inflammatory diseases (e.g., allergic rhinitis, asthma), cardiovascular diseases, neurodegenerative diseases and certain cancers. Novel formulations such as nanoparticles and liposomes are being developed to improve its poor water solubility and bioavailability, laying the foundation for its clinical application.
3. Cosmetics and Personal Care
It is increasingly added to skin care products, including anti-aging serums, moisturizers, sun care products and acne treatments. Quercetin’s ability to fight oxidative stress, reduce inflammation and protect against UV damage makes it a valuable natural active ingredient in the cosmetics industry, aligning with the trend of clean beauty and plant-based personal care.
4. Food Industry
As a natural antioxidant and preservative, quercetin is used in food processing to slow down the oxidation of food ingredients (e.g., vegetable oils, meat products and fruit juices), extending food shelf life without the use of synthetic preservatives. It is also added to functional foods (e.g., fortified beverages, cereal products) to enhance their nutritional and functional value.
5. Agriculture and Aquaculture
In aquaculture, quercetin is used as a feed additive to improve the growth performance of aquatic animals (e.g., fish, shrimp). It enhances their antioxidant capacity and immune function, reducing the risk of infectious diseases and improving survival rates. In agricultural research, it is explored for its potential to enhance plant stress resistance, supporting sustainable agricultural development.
Conclusion
Quercetin’s diverse biological benefits stem from its unique molecular structure and multi-target regulatory mechanisms, making it a highly valuable plant-derived bioactive compound. Its applications span nutraceuticals, pharmaceuticals, cosmetics, food and agriculture, with continuous research uncovering new potential uses. Despite challenges such as low bioavailability, the development of novel delivery systems is addressing this limitation, paving the way for its wider and more effective application in various fields. As research advances, quercetin will continue to play an important role in promoting human health, industrial development and sustainable production.