Understanding Medicinal Plants Instructor's Resources
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Understanding Medicinal Plants: Their Chemistry and Therapeutic Action

Prof. Bryan Hanson

Instructor's Resource Page for Chapter 5

Key Points

Chapter 5 is divided into three sections.  The first discusses the use of solubility and acid-base behavior to help students understand how the polarity of a molecule can be used to extract it from a plant.  This section then continues with a description of the process of chromatography as a means of separating an initial extract into increasingly pure fractions, guided by the use of appropriate bioassays.  The second section considers how we know the structures of molecules.  IR and 13C NMR are discussed as the most accessible techniques for determining the structure of an unknown that might be isolated from a plant (symmetry arguments and the use of a molecular formula are employed as well).  For courses in which the audience might be willing to accept that there are methods to determine structure, without worrying about what they are, one could skip over this middle section without doing damage to students’ understanding of later topics.  In my Medicinal Plants for Poets course, these first two sections are covered in the lab phase of the course.

The third section is a fairly detailed consideration of antioxidants, with an emphasis on lipid damage, the most well studied area.  Antioxidants are molecules that appear in advertising and the news frequently as an important health issue, so students are likely to be a bit familiar and quite interested in this topic.  The goal of this section, as with the rest of the book, is to show that antioxidants are not some kind of magic.  Rather, there are specific processes occuring which degrade the molecules in our body, and there are specific defense mechanisms to at least partially counteract these processes.

Learning Objectives

Teaching Ideas, Activities & Resources

Any number of published articles provide tables of the antioxidant characteristics of various materials which can be used to illustrate their value. Some specific sources you might consider include:

The background on this page is a 19th century woodcut of Phytolacca americana.
Last updated Thursday, September 1, 2011 . Contents & layout copyright 2011 Prof. Bryan Hanson