secondary metabolites in plants physiology of plants metabolites from plants metabolism of secondary metabolites

1. SECONDARY
METABOLITES
BY: HAFSA ARSHAD
BBOF17M006

2. CONTENTS
 Metabolites
 Primary and secondary metabolites
 Secondary metabolites
 Classification
 Terpenes
 Alkaloids
 Phenolics
 Glyceraldehydes
 Secondary metabolites produced by plants
 Natural colors and flavors
 Advantages and disadvantages
 Summary

3. METABOLITES
 Metabolites are intermediate
products of metabolic reactions
catalyzed by various enzymes that
naturally occur within cells.
This term is usually used to
characterized by small molecules
with various functions.
Metabolites can be characterized
into
o Primary metabolites
o Secondary metabolites
3

4. TYPES OF METABOLITES
PRIMARY METABOLITES
Molecules that are essential for
growth and development of an
organism.
Primary metabolites are involved
in maintaining normal physiological
process, thus it is referred to as
central metabolites.
Example: carbohydrates, lipids,
nucleic acid
SECONDARY METABOLITES
Molecules that are not essential
for growth and development of an
organism.
Secondary metabolites is term for
pathway for small molecules or
products of metabolism that are not
absolutely required for survival of an
organism.
Example : alkaloids, essential oils,
steroids, lignins, tannins, phenolics
4

5. DIFFERENCE BETWEEN PRIMARY AND SECONDARY
METABOLITES
PRIMARY METABOLITES
Primary metabolites are
microbial products produced
continuously during the
exponential phase of growth.
They are involved in normal
growth, development and
reproduction.
They are not poisonous.
SECONDARY METABOLITES
They are derived by pathways
in which primary metabolites are
involved.
They are not directly involved
in the normal growth,
development and reproduction.
Some of these compounds are
poisonous.
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6. SECONDARY METABOLITES
Secondary metabolites are
organic compounds produced
by plants.
Do not play any role in growth
of plant.
Required for plant survival.
Help in response to stress.
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7. SECONDARY METABOLITES
Secondary metabolites often
play an important role in plant
defense against herbivores and
other interspecies defenses.
They are often restricted to a
narrow set of species within a
phylogenetic group.
Humans use secondary
metabolites as medicines
flavoring and recreational
drugs.
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8. SECONDARY METABOLITES
8
Unlike primary metabolites,
absence of secondary
metabolites does not result
in immediate death
But rather in long-term
impairment of the organism’s
survivability, fecundity or
aesthetics or perhaps is no
significant change at all.

9. SECONDARY METABOLITES ARE DERIVED FROM PRIMARY
METABOLITES 𝑪𝑶 𝟐 + 𝑯 𝟐 𝑶
𝐏𝐡𝐨𝐭𝐨𝐬𝐲𝐧𝐭𝐡𝐞𝐬𝐢𝐬
sugarsSaponin
cardiac
Glycosides
Cycogenic
glycosides
Glucosinolates
Respiration
Acetyl-CoA Amino acids
Terpenoids
Steroids
Malonyl-CoA
protein Alkaloids
Phenols
Fatty acids
Flavonoids
Lignin
Tannins

10. CLASSIFICATION OF SECONDARY METABOLITES
Chemical structure (property of having ring, containing sugar)
Chemical composition (having nitrogen or not)
Solubility in various solvent
Secondary metabolites are classified on the basis of:
Pathway by which they are synthesized (phenylpropanoid)

11. HERE ARE THE FOLLOWING MAJOR
CLASSES OF SECONDARY METABOLITES:
TERPENES
PHENOLICS
GLYCOSIDES
ALKALOIDS
MAJOR CLASSES OF
SECONDARY
METABOLITES

12. CLASSES OF SECONDARY METABOLITES
TERPENES
Terpenes are diverse group
of organic compounds
produced by variety of
plants particularly conifers
and have strong odor.
They may protect the
plants that produce them by
deterring herbivores and by
attracting predators and
parasites of herbivores.
ALKALOIDS
Any class of nitrogenous
organic compounds of plant
origin. They include many
drugs (morphine, quinine)
and poisons (atropine).
They may act as reservoirs
for protein synthesis, as
protective substances
against animals or insects.
Function as plant stimulants
PHENOLICS
Aromatic benzene ring
compounds with one or more
hydroxyl groups produced by
plants for protection against
stress.
Play important role in plant
development, particularly in
lignin. Provide structural
integrity and scaffolding
support to plants.
GLYCOSIDES
A compound formed from a
simple sugar and another
compound by replacement
of a hydroxyl group in sugar
molecule.
Many drugs & poisons
derived from plants are
glycosides. They are stored
in in-active form & can be
activated by enzymes
1
2

13. TERPENE
Terpene are generally polymers
of 5-carbon unit called isoprene.
Terpenes are natural products
that are structurally related to
isoprene.
Terpenes are hydrocarbons
• TERPENES
Terpenoids are oxygenated hydrocarbons
• Terpenoids

14. They act upon various enzymes
to add functionality and altered
oxidation.
Terpene is composed of
isoprenoid units so it is said to
be as an isoprenoid compounds.
Give scent, flavors, colors
medicine etc.

15. TERPENES
The number of C atoms are
multiple of 𝐶5 𝐶10 𝐶15 𝐶20 𝐶30
𝐶35 𝐶40
Each group of 5C is an isoprene
unit
They can be saturated or
unsaturated
Many contain O atoms as well
What they have common is 1 & 2
above.

16. ISOPRENE UNIT
Isoprene unit is carbon skeleton of
isoprene.
The isoprene unit in terpenes do not
come from isoprene.
They come from isopentenyl
pyrophosphate.
Isopentenyl phosphate (5 carbons)
comes from acetate (2 carbons) via
mevalonate (2 carbons).

17. JOINING ISOPRENE UNITS
The term head-to-tail and
tail-to-head are often used
to describe how the isoprene
units are joined.

18. CLASSIFICATION OF
TERPENES
Terpenes are classified into many groups on
the basis of number of isoprene units:
Hemiterpene (𝑪 𝟓 𝑯 𝟖):
o Consists of a single isoprene unit
o Example: oxygen containing derivatives such
as prenol, isovaleric acid
Monoterpene (𝑪 𝟏𝟎 𝑯 𝟏𝟔):
o Consists of two isoprene units
o Example: geraniol, limonene, terpineol

19. Sesquiterpene(𝑪 𝟏𝟓 𝑯 𝟐𝟒):
o Consists of three isoprene units
o Examples: humulene, farnesene and
farnesol
Diterpene (𝑪 𝟐𝟎 𝑯 𝟑𝟐):
o Consists of four isoprene units
o Derived from geranylgeranyl
pyrophosphate
o Examples: cafestol, kahweol, cembrene
and taxadiene (precursor of taxol)
Sesterterpene (𝑪 𝟐𝟓 𝑯 𝟒𝟎):
o Consists of four isoprene units
o Examples: geranylfarnesol

20. Triterpene(𝑪 𝟑𝟎 𝑯 𝟒𝟖):
o Consists of six isoprene units
o Linear triterpene squalene and the major
constituent of shark liver oil is derived
from the reproductive coupling of two
molecules of farnesyl pyrophosphate.
o Squalene is then processed
biosynthetically to generate either
lenosterol or cysloartenol (the structural
precursors to all the steroids).
Sesquaterpene(𝑪 𝟑𝟓 𝑯 𝟓𝟔):
o Consists of seven isoprene units
o Typically microbial in their origin
o Examples: ferrugicadiol and tetraprenyl
curcumene

21. Tetraterpene(𝑪 𝟒𝟎 𝑯 𝟔𝟒):
o Consists of eight isoprene units
o Biologically active tetraterpene includes:
 Acyclic lycopene
 Monocyclic gamma-carotene
 Bicyclic alpha-carotene
 Bicyclic beta-carotenes
Polyterpene:
o Consists of long chain of many isoprene
units
o Example: Natural rubber

22. CLASSIFICATION OFTERPENES
Hemiterpene
Monoterpene
Sesquiterpene
Diterpene
Triterpene
Tetraterpene
C5
𝐶10
C15
C20
C30
C40
One
Two
Three
Four
Six
Eight
Type Of Terpene Number Of Carbon Atoms Isoprene Units
Hemi = HalfNote: Sesqui = one and half
Di = two Tri = three Tetra = four
General Formula
C5 H8
𝐶10H16
C15H24
C20H32
C30 H48
C40H64

23. TERPENES
Sesquiterpene
Monoterpene
Diterpene
Triterpene
Tetraterpene
Polyterpene
Geraniol
Limonine
Farmesole
Cafestol
Squalene
Lycopene
𝛽 − 𝑪𝒂𝒓𝒐𝒕𝒆𝒏𝒆
Gutta percha

24. ALKALOIDS
Alkaloids are compounds having a
ring structure and nitrogen residue.
They are commonly applied to
basic nitrogen compounds of plant
origin that are physiologically
active.
Organic nitrogenous compounds
with a limited distribution in native
nature

25. CHARACTERISTICS OF
ALKALOIDS
They are bitter in taste
Derived from amino acids i.e. tryptophan,
ornithine or argenine and lysine.
Amino acids that are often served as
alkaloidal precursors are:
 Phenylalanine
Tryosine
Tryptophan
Histidine
Anthranilic acid
Lysine
Ornithine.

26. Alkaloids from double salts with
compounds of mercury, gold,
platinum and other heavy metals.
 These salts are obtained as
precipitate which are microcrystals
They are widely used in medicines
Insoluble or sparingly soluble in
water
 But salts formed on reaction with
acids are usually freely soluble.

27. Most are crystalline solids although
a few are amorphous.
Free alkaloids are usually soluble in
polar solvents like ether,
chloroform.
Some alkaloids are liquid because
of lacking of oxygen in their
molecules i.e. coniine, nicotine,
spartenine.

28. SOURCES AND OCCURRENCE
OF ALKALOIDS
Alkaloids can occur in plant kingdom
among the angiosperms.
The outstanding alkaloid yielding
plants are:
 Liguminosae
 Papaveraceae
 Ranunculaceae
 Solanaceae
 Berberidaceae

29. USES OF ALKALOIDS IN
PLANTS
Poisonous agents which protect
plants against insects and herbivores
End products of detoxification
reactions representing a metabolic
locking-up of compounds otherwise
harmful to plants
For regulatory growth factors
Reserve substances capable of
supplying nitrogen or other elements
necessary to plant’s economy.

30. PHARMACOLOGIC ACTIONS OF
ALKALOIDS
Analgesic (morphene, codeine)
Narcotics (strychnine and brucine which are
central stimulant)
Anti-malarial (quinine)
Anti-pyretic
Anti-cancer (vincristine)
Mydriatics (atropine)
Anti-inflammatory
Moitics (physostigmine, pilocarpine)
Ephidrine (bronchodilator)
Reserprine (produce fall in hypertension)

31. TYPES OF ALKALOIDS
Alkaloids
True Alkaloids
(hetero cyclic)
Proto Alkaloids
(non-hetero cyclic)
Pseudo Alkaloids
Derived from
Amino Acids
Not Derived From
Amino Acids

32. Derived from amino acids
Nitrogen atom is a part of heterocyclic ring
 Pyridine- Piperidine alkaloids
 Pyrrole and Pyrrolidine alkaloids
 Quinoline alkaloids
 Isoquinoline alkaloids
 Indole alkaloids
 Imidazole alkaloids
 Norlupinane alkaloids
 Steroid alkaloids
 Purine alkaloids
TRUE ALKALOIDS

33. Not derived from amino acids
Nitrogen atom is not a part of
heterocyclic ring
 Aconitine
 Aconine
 Hypoaconitine
 Caffeine
PSEUDO ALKALOIDS

34. Derived from amino acids
Nitrogen atom is not a part of
heterocyclic ring
Alkylamides
 Ephedrine
 Pseudo ephedrine
 Epinephrine
 Amphitamine
 Colchicine
PROTO ALKALOIDS

35. PHENOLICS
Phenolic are aromatic benzene ring
compounds with one or more hydroxyl
groups produced by plants mainly for
protection against stress.
Their structure is derived from phenol
Phenols are present in every plant
They attract pollinators to the plant and
even impact that how plants act with one
another
Examples:
 Coumarin
 A vanilla-scented compound found in
many plants
 Formerly used for flavoring food

36.  LIGNIN:
 Class of complex organic polymers that form
key structural materials in support tissues of
vascular plants and some fungi.
 Abundant in formation of cell wall.
 Rigid and resistant to extraction or many
degradation reagents.
 Anthocyanin:
 Water soluble vacuolar pigments
 Depending on their pH may appear:
• Red
• Purple
• Blue
• Black
 Examples: blueberry, raspberry, black rice,
black soybean

37.  Flavones:
 A colorless crystalline compound which is
the basis of a number of white or yellow
plant pigment
 Flavnol:
 Class of flavonoids that have 3-
hydroxyflavone backbone.
 Flavanols are found in the following
plants:
• Onions
• Kale
• Grapes and red wine
• Tea
• Peaches
• Tomatoes
• berries

38. GLYCOSIDES
A compound formed from a simple sugar
and another compound by replacement of
a hydroxyl group in sugar molecule.
They are present in vacuole in inactive
form.
Many drugs and poisons derived from
plants are glycosides.
 Glycone:
 The sugar residue of glycoside
 Aglycone:
 Non-sugar fragment of a glycoside

39. CLASSIFICATION OF GLYCOSIDES
Classification of glycosides is based on the
presence/absence of sugar moieties or on the type of
glycosidic bond
There are four types of linkages between glycones and
aglycones
C-linkage
(C-glycosidie)
O-linkage
(O-glycoside)
N-linkage
(glycoslamine)
S-linkage
(thioglycoside)

40. PRODUCED BY PLANTS
SECONDARY
METABOLITES

41. CYANOGENIC GLYCOSIDES
Cyanogenic glycosides are natural
plant toxins that are present in
several plants, most of which are
consumed by humans.
They are stored in vacuole of the
plant but if the plant is attacked, they
are released by the activation of
enzymes present in cytoplasm.
They remove the sugar part of
molecule and release toxic hydrogen
cyanide.

42. Example of these cyanogenic
glycosides is amygdalin from
bitter almonds
Cyanogenic glycosides can
also be found in:
 The fruit seeds and wilting
leaves of many members of
rose family including apples,
plums, bitter almonds,
cherries, peaches, apricots,
raspberries and crabapples.

43. LATEX
Latex as found in nature is a milky
fluid found in 10% of all flowering
plants.
It is complex emulsion consisting
of proteins, alkaloids, starches,
sugars, oils, tennins, resins and
gums
In most plants latex is white but
some have yellow, orange or
scarlet
It is mostly exuded after injury
It serves mainly as defence against
herbivorous insects

44. PLANT RESINS
A liquid compound found inside plants or
exuded by plants but not saps, latex or
mucilage.
Resin produced by many plants is a
viscous liquid, mainly composed of
volatile fluid terpene.
Resins do not serve a nutritive function
o The toxic resinous compounds may
confound a wide range of herbivores,
insects and pathogens
o The volatile phenolic compounds may
attract benefactors such as parasitoids or
predators of the herbivores that attack
plants

45. PLANT STEROL
The richest naturally occurring source of
phytosterols are vegetative oils and
products made from them
They can be present in free form and as
esters of fatty acids/ cinnamic acid or as
glycosides
Phytosterols
 These are steroid compounds similar to
cholesterol which occur in plats and vary
only in carbon side chain or
presence/absence of double bond
 Stanols are saturated sterols having no
double bond in sterol ring structure.

46. ESSENTIAL OILS
An essential oil is concentrated
hydrophobic liquid containing
volatile aroma compounds from
plants.
Essential oils are also known as
volatile oils, ethereal oils,
aetherolea
They are used in:
 perfumes, cosmetics, soaps
 for flavoring foods
 For adding scents
 To incense and household cleaning
products

47. PHENYLPROPANOIDS
Phenylpropanoids are a diverse
family of organic compounds that
are synthesized by plants from
amino acid phenylalanine.
Phenylpropanoids are found
throught the plant kingdom
Provide protection from ultra-violet
light
Defend against herbivores and
pathogens
Mediate plant-pollinator
interactions as floral pigments and
scent compounds.

48. They have wide variety of
functions both as structural and
signaling molecules.
The phenylpropanoid pathway
serves as a rich source of
metabolites in plants, being
requires for the biosynthesis of
lignin.
PHENYLPROPANOIDS

49. BETTER AND SAFER ALTERNATIVES
NATURAL COLORS
AND FLAVORS

50. NATURAL COLORS
Natural colors produced by plants
are:
oSaffron
oAnthocyanin
oCarotenoids
oCarotene
oChlorophyll
oCurcumin
oIron oxides
oRiboflavin
oTitanium dioxides

51. CAROTENOIDS
Carotenoids are plant pigments
responsible for bright red, yellow and
orange hues in many fruits and
vegetables.
They act as antioxidants in human body
Have strong cancer-fighting properties
They serve two key roles in plants and
algae:
 Absorb light energy for use in
photosynthesis
 Provide photo-protection via non-
photochemical quenching
Sources
Sweet carrots, oranges, tomatoes etc.

52. CHLOROPHYLL
Chlorophyll is green colored pigment
found in mesosomes of cyanobacteria as
well as in chloroplasts of algae and
plants.
Chlorophyll is the molecule that absorbs
sunlight and uses its energy to synthesize
carbohydrates from 𝐶𝑂2 and water. This
process is known as photosynthesis.
Chlorophyll is essential in
photosynthesis.it occurs naturally in
plants.
Photosynthesis is the basis for sustaining
the life processes of all plants.

53. CURCUMIN
Curcumin is bright yellow chemical
produced by Curcuma longa plants.
Extracted from turmeric
 Food flavoring and coloring
 Wound healing
 Anti-ulcer
 Anti-inflammatory
 Herbal supplement
 Cosmetic ingredient
 Anti-microbial and anti-viral
 Hepato-protective
 Antioxidant
 No toxicity

54. RIBOFLAVIN
Also known as vitamin 𝐵2
It is water-soluble vitamin
Required for normal plant growth
and development
Riboflavin can enhance pathogen
resistance in plants
It is synthesized by all plants and
many microorganisms e.g. spinach.
Found in food and used as a dietary
supplement

55. FLAVORS
Vanilla
Vanilla is a flavoring derived from
orchids of the genus vanilla,
primarily from Mexican species
Vanilla is known as queen of all
flavors.
 Coca seeds
 Cinnamon
 Strawberry
 Cloves
 Pepper
 areca

56. SUMMARY CLASS
EXAMPLE
COMPOUNDS
EXAMPLE SOURCES
SOME EFFECTS AND
USES
ALKALOIDS
Nitrogen and sulfur
containing alkaloids
Nicotine cocaine
theobromine
Tobacco coca plant
chocolate (cocoa)
Interfere with
neurotransmission, block
enzyme action
GLYCOSIDES
Glucosinulates
Sinigrin Cabbage relatives
TERPENOIDS Monoterpenes Methanol linalool
Mint and relative
plants
Interfere with
neurotransmission, block
ion transport
sesquiterpenes Parthenoid
Parthenium and
relatives (Asteraceae)
Contact dermatitis
Terpene polymers Rubber
Hevea (rubber) trees,
dandelion
Gum up insects
PHENOLICS Phenol acids Caffeic, Chlorogenic All plants Cause oxidative damage
Cumarins Umbelliferons Text Text
Lignins Lignin All land plants
Structure, toughness,
fiber
Flavonoids Anthocyanin, Catechin Almost all plants Flavor, leaf color,
Tannins
Gallotanin, Condenced
tannin
Oak, hemlock trees
Bind to proteins,
enzymes, antioxidant
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57. ADVANTAGES AND DISADVANTAGES OF SECONDARY
METABOLITES
ADVANTAGES
Microbes :
o Fast growth
o inexpensive carbon source
o easy genetic transformation
o high levels of gene expression
o accessible genetics
o high yield
o well established scale-up technologies
o Purification
o easier and less costly.
o Microbes :
o Toxicity effects of metabolites
o Lack of compatible post-translational
modification
o Unavailability of building blocks
o Limitation in intracellular capacity for
lipophilic compounds
o Difficulty to express some eukaryotic
genes
DISADVANTAGES
5
7

58. ADVANTAGES AND DISADVANTAGES OF SECONDARY
METABOLITES
ADVANTAGES
Plant cell organ cultures:
o More reliable production
o Simple and predictable behavior
o Uniform quality and yield
o Options to produce novel compounds
o Rapid and efficient isolation of natural
products
o Lack of interfering compounds
Plant cell organ cultures:
o Endogenous pathways do not express in
most undifferentiated cell cultures
o Genetic instability of cell lines
o Aggregates low yield
o Slow growth rates
o High sensitivity to shear stress
o Scale up difficulties and toxicity effects
due to secondary metabolite production
at high levels
DISADVANTAGES
5
8

59. ADVANTAGES AND DISADVANTAGES OF SECONDARY
METABOLITES
ADVANTAGES
Whole plant:
o Inexpensive
o Simple and rapid
o Mass production at large scale
o Large biomass
Whole plant:
o Difficult to extract
o Long production time scale
o Competition of matabolites
between primary and secondary
metabolism
DISADVANTAGES
5
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60. THANKYOU