Non‐Flat Bisbenzylisoquinoline Alkaloid Fangchinoline As a Class of Potent G‐Quadruplex Stabilizer with Anti‐cancer Activity

Compounds selectively binding and stabilizing G‐quadruplex structures could inhibit the telomerase or down‐ regulate the oncogenes and may act as anti‐cancer drugs. An alkaloid with non‐flat structure, fangchinoline, showed to strongly stabilize the intermolecular and intramolecular parallel stranded G‐quadruplex structure, increasing melting temperature by 20 and 23°C, respectively. The binding mode was investigated by using NMR and molecular modelling methods. Four human cell lines (HL‐60, BGC‐823, Bel‐7402 and KB) were taken to test the anti‐proliferation effects of fangchinoline and the IC₅₀ values were ranged from 16 to 32 µmol/L. These results showed that the fangchinoline or related moiety derivatives may represent a class of telomere‐targeted agents as potential anti‐cancer drugs.