Fast screening and structural elucidation of G-quadruplex ligands from a mixture via G-quadruplex recognition and NMR methods.

Currently, there is a considerable interest in discovering G-quadruplex ligands. Plant-derived agents, because of their diversity in structure and bioactivity and low toxicity, may be a very diverse source of G-quadruplex ligands. However, up to now, the screening of G-quadruplex ligands from natural plant extract has not been reported. Herein, in order to develop a simple method for fast identifying G-quadruplex ligands from plant extract, we intended to substitute the spectral shift in the imino region (delta 10-12) in (1)H NMR spectra of G-quadruplex for in vitro bioassay to judge the existence/nonexistence of G-quadruplex ligand(s) in plant extract, and then couple G-quadruplex recognition with NMR based structure elucidation to identify the structure of the ligand(s) without the need of prior separation. In this paper, we successfully screened a G-quadruplex ligand from a simulated plant extract using this approach. This research work provides a promising tactic to find new leading compounds from nature plant extract.