Plant flavonol quercetin engenders cytotoxic effect in different pre-clinical cancer models through modulation of diverse epigenetic regulators

Plethora of consensual evidences confirm the deregulation of epigenetic regulators in multiple oncological disorders. Although the synthetic drugs are available for treating these malignancies but their use is restricted due to high expenditure and intolerable side effects. To subdue these concerns, the bioactive molecules from plants have been suggested as an alternative strategy. Quercetin, the flavonol from heterogeneous plant sources is appearing as a novel anticancer molecule. This article discusses quercetin as a promising molecule against several malignancies including leukaemia, lung, colorectal, prostate, cervical cancer, hepatocellular carcinoma, breast cancer, esophageal cancer and melanoma. Strong priority has been given to epigenetic mechanisms modulated by quercetin for generating the cytotoxic effect against the preclinical models of these cancer subtypes. Additionally, the combined therapeutic scheme involving quercetin in concert with other molecules such as hyperoside, curcumin, sodium butyrate or trichostatin A for overwhelming cytotoxic effect has also been spotlighted along with the important molecular mechanisms impacted. In addition to single and combined conventional delivery of quercetin, nanoparticle based quercetin delivery has been clarified. Moreover, its bioavailability, absorption together with distribution, metabolism and toxicity has been thoroughly explained. Necessary gaps in quercetin research that require further investigation have been identified. On the whole, quercetin has undeniable activity against aggressive cancers in discrete form which gets further heightened on systematic coupling with other therapeutic agents.