Classification of plant secondary metabolites:

Plants can be regarded as green bioreactor due to synthesis of various organic compounds including both primary and secondary metabolites. In the context of secondary metabolites it varies from species to species and genera to genera. The classification of secondary metabolites are essential for scientific study, characterization and their utilization for various purposes under consideration of human welfare.

In 2003, British Nutrition Foundation classified secondary metabolites into four categories  within  10  key facts which was entitled as “Plants: Diet and Health”.

These are- 

  • Terpenoids-  (Ex. – Carotenoids, Sterols etc.) 

  • Phenolics- (phenolic acid, flavonoids,  tannins,  lignins etc.) 

  • NCC- (Ex.- alkaloids,  non-protein amino acids, cyanogenic glucosides etc.)

  • SCC- (Ex. –  Lectins, phytoalexins, GSH, GSL etc.) 

*Remarks- NCC– Nitrogen containing compounds, SCC- Sulphur  containing compounds.

 Key concepts:

  • Over 100,000 different secondary metabolites have been identified in plants. 

  • Till date 12000 alkaloids, 10,000 phenolics and 25,000 terpenoids have identified. 

  • Many alkaloids, phenolics and terpenoids have medicinal properties.

  • A number of plant growth regulators(i.e. hormone) are derived from terpenoid entities.