Role of Mass Spectrometry in Modern Herbal Drug Research

Abstract

Herbal drugs or plant medicines have been in use since the early days of human civilization. Even now, herbal drugs are in popular demand because of their relatively low cost without side effects, unlike modern medicine. The efficacy of the herbal drug depends on the quality of the plants and their phytoconstituents which, in turn, depend on the species of the plant and environmental conditions under which they grow. Adulteration is also a contributing factor. Qualitative detection and quantitative determination of constituents are the most important physicochemical quality evaluation of herbal drugs. Analytical techniques such as NMR and MS are commonly used for metabolite profiling for the quality control of herbal drugs. The higher sensitivity of MS enables detection of trace components and hence MS is widely used for plant metabolite profiling. Basic concepts of MS are discussed before describing the applications. Coupling GC or LC with MS results in separation of the components prior to detection by MS resulting in enhanced sensitivity and specificity. The two approaches for metabolite analysis are: (1) targeted analysis of one or two marker compounds and (2) untargeted analysis involving determination of all the metabolites. Multiple reaction monitoring and parallel reaction monitoring are used for quantitative determination. The applications of MS in herbal drug research include identification and authentication, profiling, standardization, quality control, adulteration, toxicity studies, pharmacokinetic studies, MS imaging and heavy metal determination. Several examples are discussed.