Drug design strategies that aim to improve the low solubility and poor bioavailability conundrum in quercetin derivatives

Scientists are especially interested in polyphenols, particularly flavonoids. Quercetin, a flavonoid, has demonstrated various therapeutic properties, such as antioxidant, anti-diabetic, anti-hypertensive, and anti-carcinogenic activities. Different plant sources contain varying quantities and types of quercetin. However, quercetin's bioavailability is frequently low due to its low water solubility, molecular stability, and absorption characteristics.The primary goals of this review are related to the approaches for overcoming quercetin's limitations. Hence, the main tactics for structural modifications (addition of charged and polar groups, removing C2, C3 double bond or reducing aromaticity, disrupting intramolecular H-bond, and reducing crystal lattice stability) and drug delivery systems (cyclodextrin complexes, emulsions, nanoparticles, liposomes, etc.) were discussed to improve water solubility and bioavailability of quercetin.From a tactical perspective, enhancing the solubility of compounds can be simplified through decreasing hydrophobic properties or crystalline stability. In addition, an essential field of study focuses on creating appropriate molecular carriers for substances with low water solubility. However, pharmacokinetics, potency, and toxicology are all impacted by the structural factors and physical characteristics that regulate solubility. Poor water solubility is still a major problem in drug discovery, and new methods are always in demand to overcome it.