Transcript Terpenoids and Carotenoids

Terpenoids and Carotenoids
(Alkaloids)
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.
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 – 8000 compounds from Skimic acid pathway or
mevalonate/aetate pathway
* Phenolics described in previous classes
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”
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.
10
Monoterpenes
20
Diterpenes
15
Sesquiterpenes
30
Triterpenes
Recognition of the isoprene unit as a component of the structure
of terpenes has been a great aid in elucidating their structures.
Occurrence
Eucalyptus oil (Aroma)
of Terpenoids
Cinnamom (Flavour)
Zinger (Aroma)
Cloves (Flavour)
Yellow flowers (Scent)
Biosynthesis of Terpenoids
1. Bio-Synthesis of IPP (isopentenyl diphosphate )
2. Bio-synthesis of Terpenes and/or Terpenoids
from IPP
Step 1: Synthesis of IPP (Isopentenyl diphosphate)
1) Methylerythritol pathway – plastid
2) Acetate/Mevalonate pathway - ER
Step 2: Biosynthesis of terpenes or terpenoids
MEP pathway
Mev. pathway
Prenyltransferase : repetitive
Addition of C5 units
prenyltransferase
terpene synthase
prenyltransferase
terpene synthase
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…
C20 : phytol, gibberellic acid, taxol, phytoalexins…
C30 : brassinosteroids, phytoalexins, antifeedants…
C40 : carotenoid, ABA…
Polyterpenes : plastoquinnones, rubber…
Biochemistry of Terpenoids
CH2
H2C
H2C
H3C
CH3
H2C
H2C
H3C
C
C
H
C
CH
C
H2
C
CH H2C
C
CH
or
CH2
CH3
CH
C
CH3
CH3
or
CH
CH2
Many terpenes also have isoprene units linked in rings, and
Others (terpenoids) contain oxygen.
OH
 -Pinene
Limonene
(ÄûÃÊÓ;«)
(ËÉÝÆ)
Geraniol
Menthol
(ÏãÒ¶´¼)
(±¡ºÉ´¼)
The carotenes are tetraterpenes. They can be thought of as two
diterpenes linked in tail-to-tail fashion.
H3C
CH3
H3C
CH3
CH3
H3C
CH3
CH3
 -Carotene
(ºúÂÞ²·ËØ)
CH3
CH3
Taxol-Paclitaxel
Taxol is an extensively decorated terpenoid, while Phorbol is less so
(hydroxylations).
(Core terpenoid of Taxol is in yellow/bold).
Alkaloids
Nitrogen containing basic compounds of plant origin
Alkaloid biosynthesis
Most cases, from
tryptophan,
tyrosine,
phenylalanine,
lysine,
arginine
+
terpenoidtype moiety
(steroidal, secologanin,etc)
12,000 Alkaloid biosynthesis are not thoroughly understood…….
Examples of amino acid origin for some alkaloids
Tryptophan
quinine
Ornithine
Aspartate
nicotine
cocaine
Ornithine
Tyrosine
Aspartate,
Glycine,
Glutamaine
morphine
caffeine
Examples of Alkaloids with their Plant Origin
coniine
Commercially important Alkaloids
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
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 caro
tenoids, 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.
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 carotenoid
s are derived from a 40-Carbon polyene chain which could be considered the
backbone of the molecule.
The catotenes all can be converted to vitamin A
by enzymes in the liver
H3C
CH3
H3C
CH3
CH3
H3C
CH3
CH3
CH3
CH3
 -Carotene
(ºúÂÞ²·ËØ)
H3C
CH3
H3C
CH3
CH3
CH3
H3C
CH3
 -Carotene
(ºúÂÞ²·ËØ)
CH3
CH3
Important Role in Human Health
1. Carotenoids acts as biological antioxidants, protecting
ssues from damaging effects of free radicals.
cells and ti
2. Lycopene, hydrocarbon carotenoid present in Tomatoes is particul
ar effective in quenching the destructive
potential of singlet ox
ygen.
3. Lutein, Zeaxanthin and Xanthophylls found in corn and
leafy vege
tables such as kale and spinach protects from muscular degenerati
on of the human retina.
4. Astaxanthin, a xanthophyll found in salmon, shrimp and other sea f
oods provides potent antioxidant properties on their consumption.
5. Other biological properties of Carotenoids include enhancement of i
mmune system function, protection from
sunburn, and inhibiti
on of the development of certain
types of cancers.
Thank you