Elementary plant Biochemistry and Biotechnology (2+1)

Biotransformation

• Modification of an exogenous compound by plant cells (or other biological organisms) is called biotransformation or bioconversion. These reactions (esterification, oxidation, reduction, hydroxylation and glycosilation etc.,) are catalyzed by enzymes present in the plant cells. For example, cell cultures of Datura innoxia, Catharanthus roseus, Rauwolfia serpentina biotransform hydroquinone into its β-D-glucoside called arbutin. Arbutin is an efficient suppressor of melanin biosynthesis in human skin and so used in cosmetics.
Table 1. Selected examples of secondary metabolites produced by plant species.

Compound	Class of compound	Plant species	Yield (g/l)	Use of the compound
Shikonin	Napthoquinones	Lithospermum erythrorhizon	4	Antiseptic; dye for silk and cosmetics
Berberine	Alkaloid	Coptis japonica	7	Antibacterial and anti-inflammatory
Taxol	Diterpene alkaloid	Taxus spp.	-	Breast and ovarian cancer treatment
Ajmalicin	Alkaloid (indole alkaloid)	Catharanthus roseus	2	Antileukaemic