Investigation of Secondary Metabolites in Plants. A General Protocol for Undergraduate Research in Natural Products

Many plants contain compounds known as metabolites that are believed to play important roles, such as attracting insects or defending the plants from predators. Some plant metabolites have medicinal properties, and a large percentage of currently used medicines were derived from plant extracts. A general procedure is outlined for extracting, isolating, and purifying metabolites from plant specimens. A number of simple bioassays are described that can be used to ascertain the bioactivity of the extracts, and the techniques most commonly used for determining the molecular structures of the compounds are described. One example of a plant (Astragalus danicus) that has been used for medicinal purposes by indigenous people is described in detail, and several of the compounds isolated and identified from this plant are described.