Terpenoid Derivatives are a vast and diverse group of natural compounds derived from terpenes, which are built from isoprene units (C₅H₈). They form the largest class of plant secondary metabolites and are widely distributed across the plant kingdom.
Key Features
- Derived from the mevalonate (MVA) pathway or methylerythritol phosphate (MEP) pathway.
- Modified by oxidation, rearrangement, or addition of functional groups → terpenoids (aka isoprenoids).
- Structural diversity leads to wide-ranging biological functions and commercial applications.
Classification of Terpenoid Derivatives (based on isoprene units):
- Monoterpenoids (C₁₀) → Menthol, Linalool (aromas, essential oils).
- Sesquiterpenoids (C₁₅) → Farnesol, Artemisinin (antimalarial).
- Diterpenoids (C₂₀) → Taxol (anticancer), Gibberellins (plant hormone).
- Triterpenoids (C₃₀) → Saponins, Steroids (cholesterol precursors).
- Tetraterpenoids (C₄₀) → Carotenoids (β-carotene, lycopene).
- Polyterpenoids (C₅₀+) → Rubber, Dolichols.
Roles in Plants
- Defense: Against herbivores, pathogens (e.g., phytoalexins, artemisinin).
- Pigmentation: Carotenoids aid in photosynthesis and attract pollinators.
- Hormones: Gibberellins, Abscisic acid, Cytokinins regulate growth.
- Volatiles: Terpenoid scents attract pollinators, deter pests.
- Structural: Rubber and sterols maintain integrity.
Uses in Humans
- Medicinal: Artemisinin (antimalarial), Taxol (anticancer), Steroids (hormones).
- Nutritional: Carotenoids (vitamin A precursors, antioxidants).
- Industrial: Rubber, biofuels, fragrances, essential oils.