Structure−Activity Relationship Studies of Chalcone Leading to 3-Hydroxy-4,3′,4′,5′-tetramethoxychalcone and Its Analogues as Potent Nuclear Factor κB Inhibitors and Their Anticancer Activities

Chalcone is a privileged structure, demonstrating promising anti-inflammatory and anticancer activities. One potential mechanism is to suppress nuclear factor kappa B (NF-κB) activation. The structures of chalcone-based NF-κB inhibitors vary significantly that there is minimum information about their structure−activity relationships (SAR). This study aims to establish SAR of chalcone-based compounds to NF-κB inhibition, to explore the feasibility of developing simple chalcone-based potent NF-κB inhibitors, and to evaluate their anticancer activities. Three series of chalcones were synthesized in one to three steps with the key step being aldol condensation. These candidates demonstrated a wide range of NF-κB inhibitory activities, some of low micromolar potency, establishing that structural complexity is not required for NF-κB inhibition. Lead compounds also demonstrate potent cytotoxicity against lung cancer cells. Their cytotoxicities correlate moderately well with their NF-κB inhibitory activities, suggesting that suppressing NF-κB activation is likely responsible for at least some of the cytotoxicities. One lead compound effectively inhibits lung tumor growth with no signs of adverse side effects.