Hyphenated Techniques in Liquid Chromatography as Current Trends in Natural Products Analysis

Historically, drug discovery from natural products has been a time and resource-intensive process. Bioassay-guided isolation of natural products often leads to already known compounds of limited, or no chemical or pharmacological interest. Some bioactive compounds are unstable and separation using the traditional approach is often difficult. Full structural elucidation of pure compounds usually requires milligram quantities of compounds and that may require extracting large kilogram quantities of material especially for minor compounds. Rapid detection of biologically active natural products is desired, and to achieve this, dereplication of crude extracts performed prior to isolation work is of crucial importance for avoiding the isolation of a known constituent. Natural products research, as a strategy in drug discovery, has evolved over the last two decades with technological advances in the tools which are prerequisite in isolation and structural elucidation of compounds. Such is the shift from the classical/traditional stand-alone instrumental analytical approaches to newer hyphenated techniques (LC-UV/DAD, LC-MS and LC-NMR).This review describes the general principles and literature applications of these productivity tools in natural products isolation and structural elucidation and also as assay tools for quality control studies, with a discussion on their successes and intrinsic challenges. These hyphenated techniques will advance the course of natural products research and reduce the time and cost invested in the study of natural products, speeding up the drug discovery process.