CHAPTER 13 - Isolation and Purification of Secondary Metabolites

Abstract

Publisher Summary This chapter discusses the isolation and purification of secondary metabolites. Secondary metabolites, by virtue of their nature as idiosyncratic and of no vital significance to the producing organism, are often produced in very low yields by the original wild type strains. The isolation and identification of new secondary metabolites for the sake of discovering novel structure per se is no longer an activity for which there is much support, either in academic or industrial laboratories. Most natural product chemistry is directed at some biological screen and the purification process tends to follow a bioactivity-directed fractionation. This gives the chemist a tool for learning something of the nature of the metabolite prior to its isolation. After the initial identification of activity in a crude extract or fermentation broth, by quantitatively following this activity, albeit in some arbitrary and undefined units, the chemist can explore the stability, lipophilicity, ionizability, and chromatographic mobility of the active principle through the bioassay. The initial steps of a purification process usually involve many-fold purifications through simple extractions, either solid–liquid or liquid–liquid extractions, or triturations.