Semisynthetic Quercetin Derivatives with Potent Antitumor Activity in Colon Carcinoma

Quercetin has been found to possess diverse pharmacological properties including in different types of cancers. The application of quercetin in the pharmaceutical field is limited due to its poor bioavailability resulting from poor water solubility and poor permeability. We report a systematic chemical modification of quercetin toward the development of semisynthetic derivatives through a selective synthetic methodology, which enables the installation of different substitutions at C-3' and C-5 positions of quercetin. The hypothesis of the present manuscript was to modulate the log D value and aqueous solubility of quercetin through the attachment of some facilitator moieties. The semisynthetic derivatives with an ideal log D value and improved aqueous solubility will possess a better cell-penetrating ability compared to quercetin. Representative compound 17 shows 96-fold increase in the cytotoxic activity in HCT-116 colon cancer cells as compared to quercetin. The in vivo treatment of 17 in CT-26 tumor-bearing mice in a colon cancer model resulted in a striking increase in the survival rate and reduction in tumor weight (60%) with respect to quercetin. We believe that the current study has an immense potential toward the systemic development of clinically approved quercetin semisynthetic derivatives.