Inhibition of nasopharynx cancer cells by selected flavonoids <i>in vitro</i> and molecular docking analysis of BCL‑w anti‑apoptotic protein

Current treatments for nasopharyngeal carcinoma (NPC), a type of cancer that develops from the epithelium of the nasopharynx, are often associated with potential toxicities. Moreover, NPC continues to be a considerable cause of morbidity and mortality. The breakthrough of novel therapeutic strategies is crucial in order to obtain improved treatment results. B‑cell lymphoma‑w (BCL‑w) is an anti‑apoptotic member of the B‑cell lymphoma‑2 (BCL‑2) family of proteins. BCL‑w exhibits high conformational flexibility and could be exploited to develop inhibitors selective of BCL‑w. The inhibition of BCL‑w may benefit patients with cancer. Flavonoids exhibit diverse bioactivity, including anticancer activity. The present study investigated selected flavonoids, apigenin, kaempferol, luteolin, quercetin and their respective glycosides, for their inhibitory effects on NPC cells. Flavonoids were evaluated in a concentration‑ and time‑dependent manner using a colorimetric assay, and the findings were then verified using a real‑time, impedance‑based cell analyser. Molecular docking analyses were conducted on the selected flavonoids against BCL‑w as the target site. The aglycones (apigenin, kaempferol, luteolin and quercetin) were more potent than their respective O‑glycosides, while the C‑glycosides exhibited no activity on NPC cells. The molecular docking analyses of the selected flavonoids and their glycoside derivatives as ligands and the ligand binding site of BCL‑w as the target site revealed varying degrees of binding affinity to the binding site. Cynaroside had the highest binding affinity among the flavonoids evaluated. Apigenin, luteolin, kaempferol and quercetin markedly inhibited NPC cell viability. Dietary flavones and flavonols may thus provide potency on NPC cells. The results from the molecular docking analyses may be further used in designing new derivatives with improved binding affinity with BCL‑w.&nbsp;