Utilization of NMR-Based Techniques in Anticancer Drug Development

Nuclear magnetic resonance (NMR) utilizes spin changes at the nuclear level when radiofrequency energy is absorbed in the presence of magnetic field. Only nuclei with odd mass numbers (e.g., 1H, 13C, 15N) give NMR spectra because they have asymmetrical charge distribution and (2I+1) orientations. Since the discovery of NMR phenomenon in 1946 by Purcell and Bloch, it has been used for the study of both synthetic compounds and natural products. NMR has also been used to investigate dynamic molecular properties such as conformational isomerism, molecular asymmetry, hydrogen bonding, and keto-enol tautomerism. Analysis of structure-activity relationship with an NMR technique was introduced in 1996. Using this and other recently advanced NMR techniques, it is now possible to determine the binding site and pattern of a small molecule to its intended molecular target, an extremely powerful tool for the development of effective drugs. One of the most exciting new areas of research is the field of metabonomics, which relies on NMR spectroscopy of biofluids such as urine, plasma, and cerebrospinal fluid. In this review, we will focus on commonly used NMR-based screening approaches for cancer chemotherapeutics development. In doing so, we will first briefly introduce the theoretical aspect of the technique that lays the foundation of NMR-based methods. We will then discuss several different NMR techniques that are commonly used for studying interactions between model ligands and receptors. We will also describe examples of how the NMR spectroscopy has been applied to generate and optimize novel chemical classes of ligands to develop effective anticancer therapeutics. Finally, we will discuss about contributions of the metabonomic NMR spectroscopy to the analysis of drug metabolism and toxicity in the context of apoptosis and tumor control.

Keywords: NMR, spectroscopy, anticancer agent, drug development, structure activity relationship (SAR).