1. Terpenoids and Carotenoids (Alkaloids)

2. Secondary metabolites
Secondary metabolism (also called special metabolism) that are not absolutely required for the survival of the organism.
Examples of the products include antibiotics and pigments. To distinguish non-secondary ("ordinary") metabolism, the term basic metabolites is sometimes used.
Secondary metabolites are produced by microbes, plants and animal, but not by all of them.

3. The secondary metabolites are categorized by the biosynthetic origins
Based on their biosynthetic origins:
1) Terpenoids – 25,000 compounds formed from isopentenyl diphosphate (IPP)
2) Alkaloids – 12,000 compounds formed from amino acids
3) phenolics – compounds from Skimic acid pathway or
mevalonate/aetate pathway
* Phenolics described in previous classes

4. What areTerpenoids ?
Terpenoids, sometimes called isoprenoids are a large diverse class of naturally occurring organic chemicals similar to terpenes.
Terpenoids are derived from 5 carbon isoprene units
Terpenoids are derived from repetitive fusion of branched five carbon units called “isoprene”
Therefore, terpenoids are also called “isoprenoids”

5. Terpenes and Terpenoids
A terpene is a naturally occurring hydrocarbon based on combinations of the
isoprene unit. Terpenoids are compounds related to terpenes, which may include
some oxygen functionality or some rearrangement, however the two terms are
often used interchangeably .
Most terpenes have skeletons of 10,15,20 or 30 carbon atoms
and are classified in the following way.
The steroids and sterols in animals are biologically produced from terpenoid precursors. Sometimes terpenoids are added to proteins, e.g., to enhance their attachment to the cell membrane; this is known as isoprenylation.
Many of these are substrates for plant Cytochrome P450.
Recognition of the isoprene unit as a component of the structure
of terpenes has been a great aid in elucidating their structures. 5

6. Occurrence of Terpenoids
Eucalyptus oil (Aroma)
Cinnamom (Flavour)
Cloves (Flavour)
Plant terpenoids are used extensively for their aromatic qualities. They play a role in traditional herbal remedies and are under investigation for antibacterial, antineoplastic, and other pharmaceutical functions. Terpenoids contribute to the scent of eucalyptus, the flavors of cinnamon, cloves, and ginger, and the color of yellow flowers. Well-known terpenoids include citral, menthol, camphor, Salvinorin A in the plant Salvia divinorum, and the cannabinoids found in Cannabis.
Zinger (Aroma)
Yellow flowers (Scent)

7. Biosynthesis of Terpenoids
Bio-Synthesis of IPP (isopentenyl diphosphate )
2. Bio-synthesis of Terpenes and/or Terpenoids
from IPP

8. Step 1: Synthesis of IPP (Isopentenyl diphosphate)
Methylerythritol pathway – plastid
Acetate/Mevalonate pathway - ER

9. Step 2: Biosynthesis of terpenes or terpenoids
MEP pathway
Mev. pathway
Prenyltransferase : repetitive
Addition of C5 units
prenyltransferase
terpene synthase
prenyltransferase
Although both pathways, MVA and MEP, are mutually exclusive in most organisms, interactions between them have been reported in plants and few bacteria species.
terpene synthase

10. Examples of terpenoids
Terpenoids are classified by the number of 5 carbon units they contain C5
C10 : many volatile fragrance and herb or spice oils
C15 : olis, phytoalexins, antibiotics, antifeedants…
Hemiterpenoids, 1 isoprene unit
Monoterpenoids, 2 isoprene units
Sesquiterpenoids, 3 isoprene units
Diterpenoids, 4 isoprene units
Sesterterpenoids, 5 isoprene units
Triterpenoids, 6 isoprene units
Tetraterpenoids, 8 isoprene units
Polyterpenoids with a larger number of isoprene units
Terpenoids can also be classified according to the number of cyclic structures they contain.
C20 : phytol, gibberellic acid, taxol, phytoalexins…
C30 : brassinosteroids, phytoalexins, antifeedants…
C40 : carotenoid, ABA…
Polyterpenes : plastoquinnones, rubber…

11. Biochemistry of Terpenoids
Structure and classification
Terpenes are hydrocarbons resulting from the combination of several isoprene units. Terpenoids can be thought of as modified terpenes, wherein methyl groups have been moved or removed, or oxygen atoms added. (Some authors use the term "terpene" more broadly, to include the terpenoids.) Just like terpenes, the terpenoids can be classified according to the number of isoprene units used:
Many terpenes also have isoprene units linked in rings, and
Others (terpenoids) contain oxygen.

12. The carotenes are tetraterpenes. They can be thought of as two
diterpenes linked in tail-to-tail fashion.

13. Taxol-Paclitaxel (Core terpenoid of Taxol is in yellow/bold).
Taxol is an extensively decorated terpenoid, while Phorbol is less so (hydroxylations).
(Core terpenoid of Taxol is in yellow/bold).

14. Nitrogen containing basic compounds of plant origin
Alkaloids
Nitrogen containing basic compounds of plant origin
Alkaloid biosynthesis
Most cases, from
tryptophan,
tyrosine,
phenylalanine,
lysine,
arginine
terpenoid-
type moiety
(steroidal, secologanin,etc) +
12,000 Alkaloid biosynthesis are not thoroughly understood…….

15. Examples of amino acid origin for some alkaloids
quinine
Tryptophan
Ornithine
Aspartate
nicotine
cocaine
Ornithine
morphine
Tyrosine
Aspartate,
Glycine,
Glutamaine
caffeine

16. Examples of Alkaloids with their Plant Origin
coniine

17. Commercially important Alkaloids

18. Carotenes/Carotenoids What are Carotenoids?
Carotenoids are a class of natural fat-soluble pigments found principally in plants, algae and photosynthetic bacteria, where they play a critical role in photosynthetic process.
Carotenoids-Natural Pigments
Eg: Fruits, leafy vegetables and flowers

19. Introduction
Carotenoids are responsible for many of the red, orange and yellow colors of plants, leaves, fruits and flowers as well as in some birds, insects, fish and crustaceans.
Eg: 1. Orange color of Carrots and Citrus fruits
2. Red color of Peppers and Tomatoes
Although animals appear to be incapable of synthesizing carotenoids, many animals obtain carotenoids from their diet.
Within animals carotenoids provide bright coloration, serve as anti-oxidants, and can be a source for Vit. A activity.
In addition to their role in coloration, natural pigments carry out a variety of important biological functions.

20. Biosynthesis and Structure of Carotenoids
Biosynthesis of Carotenoids is same as that of Terpenoids
Polyterpenes with C40 are Carotenoids.
Carotenoids are defined by their chemical structure. The majority carotenoids are derived from a 40-Carbon polyene chain which could be considered the backbone of the molecule.

21. The catotenes all can be converted to vitamin A
by enzymes in the liver

22. Important Role in Human Health
Carotenoids acts as biological antioxidants, protecting cells and tissues from damaging effects of free radicals.
Lycopene, hydrocarbon carotenoid present in Tomatoes is particular effective in quenching the destructive potential of singlet oxygen.
Lutein, Zeaxanthin and Xanthophylls found in corn and leafy vegetables such as kale and spinach protects from muscular degeneration of the human retina.
Astaxanthin, a xanthophyll found in salmon, shrimp and other sea foods provides potent antioxidant properties on their consumption.
Other biological properties of Carotenoids include enhancement of immune system function, protection from sunburn, and inhibition of the development of certain types of cancers.

23. Thank you