Spatio-temporal imaging and high-resolution mass spectrometry analysis: New avenues in herbal drug discovery and plant metabolomics

Plant secondary metabolites confer pharmacological activities to the plant. The identification of the secondary metabolites, their tissue specific content, and spatio-temporal distribution has opened new avenues for discovery of metabolite synthesis pathways in plants. Plant metabolomics is an emerging field in plant sciences that utilizes techniques for characterization, differentiation, and activity identification of secondary metabolites. With advancement in state-of-the art technology for the study of metabolites, researchers have focused their attention towards non-invasive and intact sample analysis by application of various imaging and mass spectrometry techniques. These techniques include micro-computed tomography (micro-CT), magnetic resonance imaging (MRI), and several systems utilizing mass spectrometry. These computationally assisted techniques help in exploration of complex interactions that exist between the spatial distribution and molecular composition of metabolites leading to biological variability in plants and their potency. Through various studies reported till date, the application of these techniques for identification of novel plant secondary metabolites that may serve as candidate new drugs is demonstrated. This chapter focuses on the principles and applications of imaging and mass spectrometry techniques in plant metabolomics. These techniques serve as the future of molecular mapping in plants and they open new avenues for quality control and discovery in herbal medicine.