A Review of Various Pharmacological Effects of Quercetin with its Barriers and Approaches for Solubility and Permeability Enhancement

Abstract

Background: Quercetin, one of the most beneficial flavonoids, has been included in the human diet due to its therapeutic effect on health. Recently, quercetin has been gaining scientific attraction for its multifarious activities, including anti-oxidant, anti-inflammatory, antiviral, anti-diabetic, anti-cancer, and anti-arthritic activities and its function in easing some cardiovascular diseases. However, these applications of quercetin in the pharmaceutical field are limited due to its poor aqueous solubility and poor permeability. Objective: The present review summarizes various pharmacological activities of quercetin, analyzes the barriers like solubility and permeability, which restrict the therapeutic efficiency of quercetin, and also discusses novel approaches to enhance aqueous solubility and permeability of quercetin for its effective clinical use. Methods: The current review information sources were peer-reviewed relevant scientific articles of recognized journals from scientific engines and databases (Scopus, Web of Science, PubMed, Science Direct, Google Scholar) using different keywords related to quercetin pharmacological effects, mechanism, solubility, permeability, absorption barriers, and formulation approaches. Results: Various novel approaches, including solid dispersions, inclusion complex, pro-drugs, nanoemulsion, micelles, liposomes, SNEEDS, and microspheres, have been developed to overcome the solubility and permeability barriers for efficient quercetin delivery. Conclusion: This review revealed that the multifaceted pharmacological activities of quercetin for the management of various diseases are enormously dependent on the development of novel and safe drug delivery systems of quercetin.