Quercetin - A Super Food For Therapeutic Interventions
Mohini Sikarwar, Centre for Development of Biomaterials and Department of Life Sciences, Sharda School of Basic Sciences and Research, Sharda University
Piyush Kumar Gupta, Centre for Development of Biomaterials and Department of Life Sciences, Sharda School of Basic Sciences and Research, Sharda University
Quercetin, a flavonoid present in many fruits and vegetables, has been consumed by humans for countless generations. Studies on its antioxidant, antibacterial, anti-inflammatory, antiviral, and anticancer effects have been thorough. As a possible treatment for various inflammatory disorders, quercetin's anti-inflammatory characteristics include reducing the synthesis of inflammatory cytokines and enzymes.
Quercetin: A Super Food
Quercetin, a member of the flavonoid family found in regularly consumed foods, has received interest in nutrition circles for its ability to alter various biological processes. Quercetin is a yellow, crystalline substance with a bitter taste that is entirely insoluble in cold water, soluble in lipids and alcohol, and very slightly soluble in hot water [1]. It is a nutritional flavonoid with even more antioxidant capacity than vitamins C and E. The powerful antioxidant qualities of quercetin allow it to scavenge free radicals, decrease oxidative stress, and protect against cellular damage. Quercetin's anti-inflammatory characteristics include suppressing the synthesis of inflammatory cytokines and enzymes, making it a viable treatment for various inflammatory disorders. Free radicals are neutralised by flavonoids such as quercetin, which aid in their fight. This may lessen the chance of chronic illnesses by shielding the body's cells from oxidative damage. With its potent effects on immunity and inflammation brought on by leukocytes and other intracellular signals, quercetin is regarded as the most widely distributed and well-known flavonoid generated from nature [2].
Dietary sources of Quercetin
Eating foods high in quercetin or taking a quercetin supplement can help maintain a healthy inflammatory response by controlling the release of cytokines, which allow immune cells to interact with one another and coordinate the immune response. The primary natural dietary sources of quercetin are fruits and vegetables. Good food sources of QC include:
Table 1: QC-rich food sources
| Food Source | QC in mg/100gm |
| Capers | 233 |
| Onion | 22 |
| kale | 23 |
| Chili pepper | 32.6 |
| Apple | 4.7 |
| Green tea | 2.7 |
| Spinach | 27.2 |
| Blueberries | 9.92 |
| Cherries | 2.7 |
| Tomatoes | 2.7 |
| Cilantro | 53.0 |
| Okra | 24 |
| Radish | 70.37 |
| Fennel leaves | 49.0 |
Mechanism in body
Epidemiological studies have generally demonstrated the preventive benefits of flavanols and flavones against cardiovascular disorders and cancer. Quercetin has been shown to encourage outcomes against atopic disorders, cancer, diabetes, heart disease, allergies, and asthma, both in vitro and in vivo. Bioavailability refers to the degree to which a molecule is broken down, absorbed, metabolised, and excreted following food consumption. When quercetin is broken down in the human body, it is quickly metabolised via glucuronidation, sulfation, and methylation in the small intestine, liver, and kidneys, among other places. When quercetin is broken down in the human body, it is quickly metabolised via glucuronidation, sulfation, and/or methylation in the small intestine, liver, and kidneys, among other places. The small intestine is where quercetin is mostly absorbed after consumption; the stomach only absorbs trace levels of the compound. Consuming quercetin as a component in cereal bars rather than in capsule form improves its bioavailability. Its higher absorption could be connected to the production method, which produces a uniform solid dispersion of quercetin with other grain constituents [3].
Therapeutic Uses
As an antioxidant and anti-inflammatory, quercetin may help lower blood pressure, control blood sugar, and stave off heart disease. Also, many researchers have suggested that supplemental quercetin has been linked to improved immune system performance, weight control, and cognitive health. Quercetin has been investigated for several ailments and has demonstrated many possible advantages, including boosting immunity and lowering the risk of illness. Some of quercetin's primary health advantages are as follows:
Antioxidant activity - Cardiomyocyte apoptosis or necrosis, lipid peroxidation, intracellular protein denaturation, mitochondrial DNA damage, and inflammation can all result from oxidative stress. Quercetin possesses potential antioxidant properties because of the phenolic hydroxyl group and the double bond. As a potent ROS scavenger, quercetin shields the organism against oxidative stress. The antioxidant impact can assist the body in staying in a stable state, prevent ageing prematurely, and lower the chance of developing chronic illnesses [4].
Anticancer activity - By controlling epigenetics, quercetin can affect the growth of tumors by directly influencing the miRNA’s expression and DNA methylation levels, which can have an anticancer impact and make tumor cells more susceptible to chemotherapy. Research suggests quercetin may be a viable treatment option for glioblastoma multiforme. Through its ability to control signal molecules and stop the cell cycle, quercetin, when coupled with a range of small-molecule medications, can lower the dosage of anticancer treatments while also improving overall efficacy and safety. In many experiments, Quercetin has been demonstrated to play a significant role in increasing apoptosis, preventing metastasis, and regulating the cell cycle and tumor angiogenesis in numerous in vivo and in vitro tests [5,6].
Cardioprotective - Quercetin protects heart health in several ways. It has been demonstrated to lower blood pressure on both a systolic and diastolic level. Additionally, quercetin has been shown to lower triglycerides and total cholesterol. It also can lessen artery pressure. Additionally, quercetin can aid blood vessel regeneration, enhancing blood flow and promoting heart health [7].
Antimicrobial - Quercetin has been shown in several investigations to possess broad-spectrum antibacterial activities. Its antibacterial properties are related to its solubility and interactions with bacterial cell membranes. Furthermore, quercetin inhibited the development of bacteria by working in concert with other chemotherapeutic agents and antibiotics. Quercetin is beneficial against germs that impact the respiratory, digestive, and urinary systems and the skin. It has also been demonstrated to fight against various fungi and viruses [8].
Neuroprotective - Numerous studies have been conducted on quercetin's neuroprotective properties. It counteracts neuron cell toxicity by inducing oxidative stress at low micromolar doses. The most prevalent cause of dementia in older people is Alzheimer's disease. It erodes thinking and memory over time. Quercetin is a member of the flavonoid family of antioxidants. It has been the subject of much research due to its anti-inflammatory and antioxidant properties, critical in preventing Alzheimer's. Additionally, the researchers discovered that the quercetin group had higher motivation overall, decreased depression symptoms, and superior cognitive function ratings [9].
Antiviral activity - Numerous viruses, such as the human immunodeficiency virus (HIV), poliovirus, respiratory virus, Sindbis virus, Mayar virus, and H5N1 virus, are susceptible to the antiviral actions of quercetin and its derivatives. Because quercetin can block the early phases of virus infection, interact with proteases crucial for viral replication, and reduce infection-related inflammation, it has been shown in several trials to have potential value as an antiviral medication. There is proof that the coadministration of quercetin and vitamin C has a synergistic antiviral effect because of the antiviral qualities of ascorbic acid and quercetin's ability to be recycled by ascorbate, which increases quercetin's potency. Moreover, the food and feed industries may benefit from quercetin antioxidant therapy to avoid mycotoxin damage [10].
Summary
Many phytochemicals extracted from various natural sources have been considered to exhibit therapeutic promise for many ailments. Quercetin is one of the most widely used and physiologically active of these medicines. It is widely accessible in various complete, plant-based meals and teas. You can also get a quercetin in supplement form. Although several studies have revealed multiple possible advantages of quercetin, most have been conducted on animals or in vitro. More human studies are needed to understand the advantages and adverse effects properly. If you are considering taking quercetin supplements, consult with your doctor first to learn more about the potential benefits and effects based on your health.
References
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Mohini Sikarwar is a PhD Scholar at Centre for Development of Biomaterials, Sharda University, Greater Noida, India. Her research is focusing on advanced drug delivery systems with a commitment to enhancing therapeutic efficacy of poorly water-soluble drug for Leishmaniasis treatment. She is aiming to revolutionise the current treatment methods of Kala azar using drug delivery approaches.
Dr. Piyush Kumar Gupta is currently head of the Centre for Development of Biomaterials at Sharda University, Greater Noida, India. His area of expertise belongs to Biomaterials, Pharmaceutics, and Nanotoxicology. He has published 143 SCIE and Scopus-indexed peer-reviewed articles and 7 book chapters in his area of expertise. He has been bestowed with several International or National awards.
