The document discusses primary and secondary metabolism in plants. Primary metabolism produces primary metabolites like carbohydrates, proteins, lipids and nucleic acids that are essential for growth and survival. The pathways for primary metabolism are essentially the same across organisms. Secondary metabolism produces secondary metabolites that are not essential for growth but provide functions like defense against predators through toxicity, attracting pollinators or dispersing seeds. Secondary metabolites have more limited distribution between taxa and their roles are often unclear.

1. PRIMARY & SECONDARY
METABOLITES
SUBJECT: Pharmacognosy
COURSE: B Pharmacy V SEM
FACULTY NAME: Dr Manisha Bhatia
Associate professor
MMCP,MMU, Mullana

2. • Despite the extremely varied characteristics of living organisms, the
pathways for generally modifying and synthesizing carbohydrates,
proteins, fats, and nucleic acids are found to be essentially the same
in all organisms, apart from minor variations.
• These processes demonstrate the fundamental unity of all living
matter, and are collectively described as ‘primary metabolism’, with
the compounds involved in the pathways being termed ‘primary
metabolites’.
• Thus degradation of carbohydrates and sugars generally proceeds
via the well-characterized pathways known as glycolysis and the
Krebs/citric acid/tricarboxylic acid cycle, which release energy from
the organic compounds by oxidative reactions. Oxidation of fatty
acids from fats by the sequence called β-oxidation also provides
energy.

3. • In contrast to these primary metabolic pathways, which
synthesize, degrade, and generally interconvert compounds
commonly encountered in all organisms, there also exists an
area of metabolism concerned with compounds which have a
much more limited distribution in nature.
• Such compounds, called ‘secondary metabolites’, are found in
only specific organisms, or groups of organisms, and are an
expression of the individuality of species. Secondary
metabolites are not necessarily produced under all conditions,
and in the vast majority of cases the function of these
compounds and their benefit to the organism is not clear.

4. • Some are undoubtedly produced for easily appreciated
reasons, for example,
• as toxic materials providing defence against predators
• as volatile attractants towards the same or other species, or
as colouring agents to attract or warn other species, but it is
logical to assume that all do play some vital role for the well-
being of the producer.
• It is this area of ‘secondary metabolism’ that provides most of
the pharmacologically active natural products.

5. • PRIMARY METABOLITES: Molecules that are essential for
growth and development of an organism. Examples:
• 1.Carbohydrates 2.Proteins 3.Lipids
• 4.Nucleic acids 5.Hormones
• SECONDARY METABOLITES: Molecules that are not
essential for growth and development of an organism and are
biosynthetically derived from primary metabolites. They are
more limited in distribution being found usually in specific
families.
• 1. Terpenoids 2. Nitrogen containing compounds
• 3. Phenolics

6. Primary plant metabolites are considered as basic plant
constituents.
They are simple in structure & do not have any biological or
pharmacological activity associated with them.
They are utilized by plants for building up their body &
responsible for physiological functioning of the plant body.
There are distinct pathways and chain of reactions through
which they are synthesized or produced known as basic
metabolic pathways.
Kreb cycle, citric acid, glycolysis for degradation of
carbohydrates, oxidation of fatty acids by beta oxidation are
primary metabolic raections.

7. • Secondary metabolites are biosynthesized from primary
metabolites.
• These are potent in action & associated with marked
pharmacological actions on human body known as active
constituents.
• The quantity of active constituents ( secondary metabolites)
determines the intrinsic important role in the process of
biosynthesis.
• Main classes are polyketides, fatty acids, terpenoids, steroids,
alkaloids and specialize amino acids and carbohydrates.

8. • Secondary metabolites are those metabolites which are often
produced in a phase of subsequent to growth, have no
function in growth, are produced by certain restricted
taxonomic groups of microorganisms, have unusual
chemicals structures, and are often formed as mixtures of
closely related members of a chemical family.
• The simplest definition of secondary products is that they are
not generally included in standard metabolic charts.
• Plants produce a large, diverse array of organic compounds
that appear to have no direct function in growth, development,
photosynthesis, respiration, solute transport, translocation,
protein synthesis, nutrient assimilation differentiation, or the
formation of carbohydrates called as secondary metabolites.

9. • Thus small organic molecules produced by an organism that
are not essential for their growth, development and
reproduction are called secondary metabolites.
• They may include pharmaceuticals, flavours, fragrance, food
additives, feedstock etc. Possibly over 250,000 secondary
metabolites in plants.
• Classified based on common biosynthetic pathways where a
chemical is derived.
• Four major classes: Alkaloids, glycosides, phenolics,
terpenoids

10. • Plant secondary metabolites are a diverse group of molecules
that are involved in the adaptation of plants to their
environment but are not part of the primary biochemical
pathways of cell growth and reproduction.
• These compounds play many important rules in plant life
such as involved in defense against herbivores and
pathogens, regulation of symbiosis, control of seed
germination, and chemical inhibition of competing plant
species (allelopathy), and therefore are an integral part of the
interactions of species in plant and animal communities and
the adaptation of plants to their environment.

11. • Higher plants synthesize these wide variety of low molecular
weight compounds called secondary metabolites in addition to
the essential primary metabolites.
• These offer protection against pests, they act as attractants
and as the plant’s own hormones. Chemically meant to
protect plants from the attacks by predators, pathogens, or
competitors.
• Attract pollinators as seed dispersal agent
• Important for abiotic stress
• Medicine
• Industrial additives

12. • In addition, plant secondary metabolites are also
associated with improved nutritive value and may have
beneficial effects on animal health.
• Growing interest in the potential health-promoting
effects of plant secondary metabolites in human foods
has prompted research on their potential to prevent or
treat cancer, circulatory disease, and viral infection and
many more life threatning diseases.

13. • A metabolic intermediate or product, found as a differentiation
product in restricted taxonomic groups, not essential to growth
and the life of the producing organism, and biosynthesis from
one or more general metabolites by a wider variety of
pathways than is available in general metabolism.
• They have a wide range of chemical structures and biological
activities. They are derived by unique biosynthetic pathways
from primary metabolites and intermediates.
• These biochemical pathways are not necessary for growth or
reproduction of an organism, but which can be demonstrated
genetically, physiologically or biochemically.

14. • Plants produce an amazing diversity of low molecular weight
compounds.
• The ability to synthesize secondary metabolites has been
selected through the course of evolution in different plant
lineage when such compounds address specific needs.
• Floral scent volatiles and pigments have evolved to attract
insect pollinators and thus enhance fertilization.
• To synthesize toxic chemical has evolved to ward off
pathogens and herbivores or to suppress the growth of
neighboring plants.

15. • Chemicals found in fruits prevent spoilage and act as signals
(in the form of color, aroma, and flavor) of the presence of
potential rewards (sugars, vitamins and flavor) for animals
that eat the fruit and thereby help to disperse the seeds.
• Other chemicals serve cellular functions that are unique to the
particular plant in which they occur (e.g. resistance to salt or
drought).

16. • Primary metabolism
• The biological reactions are essential to maintain life in living
organisms and are known as primary metabolism.
• Plant convert sunlight energy to chemical energy, such as
ATP, NADPH, by the mediation of chlorophyll in chloroplasts
and synthesize sugars and starch from CO2 by using ATP
and NADPH+.
• These carbohydrates are stored and used for differentiation
and formation of plant tissues.

17. • All organisms need to transform and interconvert a vast
number of organic compounds to enable them to live, grow
and reproduce.
• All organisms need to provide themselves with energy in the
form of ATP, and a supply of building blocks to construct their
own tissues.
• An integrated network of enzyme-mediated and carefully
regulated chemical reactions in used for this purpose,
collectively referred to as intermediary metabolism, and the
pathways involved are termed metabolic pathway.
• These processes demonstrate the fundamental unity of all
living matter, and are collectively described as primary
metabolism, with the compounds involved in pathways being
termed primary metabolites.

18. • The pathways for modifying and synthesizing carbohydrates,
proteins, fats and nucleic acid are found to be same in all
organisms, apart from minor variations.
• These processes demonstrate the fundamental unity of all
living matter and are collectively described as primary
metabolism with the compounds involved in pathways are
termed as primary metabolites.

19. • Secondary metabolism
• The metabolism which are not directly related to maintaining
life, are known as secondary metabolism.
• The products formed by secondary metabolism are called
secondary metabolites.
• Secondary metabolite play a role in reinforcement of tissue
and body (e.g. cellulose, lignin, suberin), protection against
insects, diseases, and plant regulation (plant hormones).

20. • The compounds which synthesized from the secondary
metabolisms are so-called secondary metabolites.
• Secondary metabolites are formed in only specific organisms,
or groups of organisms, and are expression of the individuality
of species.
• Secondary metabolites are not necessarily produced under all
conditions, and in the vast majority of cases the function of
these compounds and their benefit to the organism is not yet
known.
• It is this area of secondary metabolism that provides most of
the pharmacologically active natural products.

21. • They are classified on the basis of:
• 1) chemical structure
• 2) chemical composition
• 3) solubility in various solvents
• 4) pathways by which they are synthesized

22. • A simple classification of secondary metabolites includes
three main groups:
• 1) the terpenes- made from mevalonic acid, composed almost
entirely of carbon and hygrogen
• 2) phenolics – made from simple sugars, containing benzene
rings, hydrogen and oxygen
• 3) nitrogen-containing compounds – extremely diverse, may
also contain sulphur

23. • To make such compounds plants utilize very specific
enzymes each of which catalyzes a specific metabolic
reaction.
These enzymes are proteins called as organic catalyst coded
by specific genes in the plants DNA.
These series of enzymatically catalyzed reactions in a well
defined sequence of step is termed as a metabolic pathway.