Alkaloids are distributed in plant kingdom and play important role in protection, germination as well as plant growth stimulants. Most of them are chiral compounds and are clinically administered as the racemic mixture, even though its enantiomers have been known to exert different pharmacological activity. Liquid chromatography using chiral stationary phases (CSP) proved to be an essential tool with a wide range of applications, including analysis of the stereochemistry of natural compounds. This review gives an overview of chiral separation alkaloids that were used in theoretical studies and/or applications in recent years. It shows the possibilities of polysaccharide CSPs have now also been established as the first-choice of chiral phases for enantiomer separation.
Part of the book: Current Topics in Chirality
Chiral inversion is always mediated by enzymes and varies with solvent, pH and temperature. Considerable attention should be paid to the mechanism of the inversion reaction and its pharmacological and toxicological results. This chapter will discuss the mechanism of chiral inversion of plants in secondary metabolize and its importance in creating pharmacology consequences. Plant stereoisomers of alkaloids and flavonoids exhibit a wide range of pharmacological effects. Recent advances in chiral analysis for the herbal plants in clinical research & forensic toxicology by experiments in which one enantiomer was given to the experiment subjects in a specific situation. Demonstration of metabolic chiral inversion may have consequences for the development of a new pharmaceutical entity. Hence, it helps a better understanding of chiral compounds in plants, facilitating the application for drug development from medicinal herbs and thereby reducing bioanalytical and toxicology workload.
Part of the book: Secondary Metabolites
In this chapter, we present mixed-mode stationary phases and their applications in the determination of nonpolar, polar, and charged compounds, as well as larger molecules such as peptides or proteins using a single column. Mixed-mode chromatography (MMC) has been growing rapidly in recent years, owing to the new generation of mixed-mode stationary phases and a better understanding of multimode interactions. Mixed-mode chromatography provides a wide range of selectivities and adequate retention of a variety of compounds, especially polar and charged molecules. In summary, this technique is particularly useful in the pharmaceutical analysis of drugs, impurities, biopharmaceuticals, and polar compounds in natural products.
Part of the book: Analytical Liquid Chromatography
Plants have evolved the capacity to create a wide range of chemicals during the process of their existence. In contrast to specialized metabolites that accumulate in a small number of plant species, flavonoids are broadly distributed across the plant kingdom. Therefore, a detailed analysis of flavonoid metabolism in genomics and metabolomics is an ideal way to investigate how plants have developed their unique metabolic pathways during the process of evolution. Among the analysis methods used for flavonoids, the coupling of liquid chromatography (LC) with ultraviolet (UV) and/or electrospray ionization (ESI) mass spectrometric detection has been demonstrated as a powerful tool for the identification and quantification of phenolics in plant extracts. This chapter mainly introduces of chemistry and metabolism of flavonoids and the application of liquid chromatography in the analysis of plant flavonoids.
Part of the book: Flavonoid Metabolism