Recent Advances in Liposomal Drug Delivery System of Quercetin for Cancer Targeting: A Mechanistic Approach.

Quercetin (QT, 3,3',4',5,7-pentahydroxyflavone), is a natural flavonoid with nutritional value and acts as a potential free-radical scavenger (antioxidant). QT has also been explored for its anti-cancer as well as anti-proliferative activities against numerous cancerous cells. Moreover, QT exhibits significant pro-apoptotic activity against tumor cells and is well established to control the growth of different carcinoma cells at various phases of the cell cycle. Hence, it can reduce the burden of human solid cancer and metastasis. Both these activities have been established in a diverse class of human cell lines in-vitro as well as in animal models (in-vivo). Apart from the promising therapeutic activities of QT molecule, their applications have been limited due to some major concerns, including low oral bioavailability and poor aqueous solubility. Also, rapid gastrointestinal digestion of QT seems to be a key barrier for its clinical translations for oral drug delivery in conventional dosage form. Henceforth, to overcome these drawbacks, QT is loaded with liposomal systems, which exhibit promising outcomes in the upregulation of QT by the epithelial system and also improved its targeting at the site of action. Furthermore, Liposomes based Drug Delivery Systems (LDDS) have showed significant therapeutic activity with conjugated drug moiety and exhibit safety, biocompatibility, biodegradability, and mitigated toxicity despite having certain limitations associated with physiological and biological barriers. Herein, in this review, we have focused on the mechanism related with the chemotherapeutic activity of QT and also discussed the promising activity of QT-loaded LDDS as a potent chemotherapeutic agent for cancer therapy.