Quercetin as a Therapeutic Product: Evaluation of Its Pharmacological Action and Clinical Applications—A Review

Abstract

Quercetin is the major polyphenolic flavonoid that belongs to the class called flavanols. It is found in many foods, such as green tea, cranberry, apple, onions, asparagus, radish leaves, buckwheat, blueberry, broccoli, and coriander. It occurs in many different forms, but the most abundant quercetin derivatives are glycosides and ethers, namely, Quercetin 3-O-glycoside, Quercetin 3-sulfate, Quercetin 3-glucuronide, and Quercetin 3′-metylether. Quercetin has antioxidant, anti-inflammatory, cardioprotective, antiviral, and antibacterial effects. It is found to be beneficial against cardiovascular diseases, cancer, diabetes, neuro-degenerative diseases, allergy asthma, peptic ulcers, osteoporosis, arthritis, and eye disorders. In pre-clinical and clinical investigations, its impacts on various signaling pathways and molecular targets have demonstrated favorable benefits for the activities mentioned above, and some global clinical trials have been conducted to validate its therapeutic profile. It is also utilized as a nutraceutical due to its pharmacological properties. Although quercetin has several pharmacological benefits, its clinical use is restricted due to its poor water solubility, substantial first-pass metabolism, and consequent low bioavailability. To circumvent this limited bioavailability, a quercetin-based nanoformulation has been considered in recent times as it manifests increased quercetin uptake by the epithelial system and enhances the delivery of quercetin to the target site. This review mainly focuses on pharmacological action, clinical trials, patents, marketed products, and approaches to improving the bioavailability of quercetin with the use of a nanoformulation.

An Overview of the Spices Used for the Prevention and Potential Treatment of Gastric Cancer

“…The antioxidant, anti-inflammatory, antibacterial, and antiviral effects of the substance have been described. It also has its part to play in the treatment of cardiovascular diseases, cancer, metabolic disorders, and neurodegenerative diseases [189]. The exact molecular mechanisms of quercetin useful for GC therapy are being sought and require further research.…”

“…Research is being conducted into the use of quercitin glucosides, which are more bioavailable than the basic form. It is indicated that nano-quercitin has higher efficacy [189,191]. Another potential way to increase the bioavailability of quercetin is through cryopreservation and microencapsulation [193].…”

Cardioprotective Effect of Hydroalcohol Extract of Andaliman (Zanthoxylum acanthopodium DC.) Fruits on Doxorubicin-Induced Rats

“…Histopathology was performed to see damage to the heart organ. Quercetin was used as a comparison because of its antioxidant and cardioprotective properties, which are helpful against cardiovascular disease [ 30 ]. The phytochemical constituent analysis of the extract was also carried out using LC-HRMS, and chemical element analysis was performed using GC-MS.…”