chapter  4
Medicinal Plants: Molecular Biology/Biotechnology Approach
Pages 28

Throughout the history, plants have been used as the main source of valuable biologically active compounds. These secondary plant metabolites are often very expensive on the market, as they are found only in rare plants and in low quantities. For example, Paclitaxel (more commonly known as Taxol®), a widely prescribed anticancer agent, is present at extremely low levels (0.015% dry weight) in slow-growing Taxus brevifolia. The aerial parts of selected varieties of Artemisia annua contain only 0.5-1.16% of the antimalarian drug on a dry weight basis. Catharathus roseus contains more

4.1 Introduction .................................................................................................... 51 4.2 Plant Cell and Tissue Culture: An Alternative Production System

for Pharmaceuticals ........................................................................................ 52 4.2.1 Micropropagation ............................................................................... 52 4.2.2 Plant Cell Cultures ..............................................................................54 4.2.3 Tissue Cultures ................................................................................... 55 4.2.4 Bioreactors .......................................................................................... 56

4.3 Genetic Modulation of Metabolic Pathways in Medicinal Plants .................. 57 4.3.1 Transfer Technology ........................................................................... 57

4.3.1.1 Agrobacterium-Mediated Transformation ........................... 57 4.3.1.2 Particle Bombardment ......................................................... 59

4.3.2 Gene Discovery and Functional Genomics ........................................60 4.4 Metabolic Engineering of Medicinal Plants ................................................... 62

4.4.1 Alkaloids ............................................................................................. 62 4.4.2 Terpenoids ........................................................................................... 67 4.4.3 Phenylpropanoids ................................................................................68