B.Pharmacy final year

1. Surendra Kumar
Assistant Professor
Kamla Nehru Institute of Management and Technology
(Faculty of Pharmacy), Sultanpur
Chemistryguru10@gmail.com

2. CHEMISTRY OF NATURAL PRODUCTS
 Introduction
 Classification of Natural Products
 Primary metabolites
 Secondary metabolites
Main classes of Natural Products
 Terpenoids and steroids
 Fatty acids (polyketide)
 Alkaloids
 Non- ribosomal (polypeptide)
Enzyme cofactor
 Natural Products in medicine
Isolation of Natural Products

3. Introduction
 Natural Products are organic and inorganic compounds that are found in
various natural sources-animal, plant and microbes.
 Natural Products can be entire –organism like as plant, animal or micor-
organism. A part of an organism (leaves or flower of plant, isolated animal
organ. An extract of an organism or an exudates or pure compound (alkaloids,
coumarins, flavonids, steroids and terpenoids) isolated from plant, animal or
micro-organism.
 In Practice, the term Natural Products refers to secondary metabolites small
molecules produced by an organism.
 Alkaloids such as morphine, eicosanoids such as prostaglandin E1, antibiotics
such as erythromycin and penicillin are good example of secondary metabolites.

4. Classification of natural Products
 Classifying natural products- their immense diversity in structure, function and
biosynthesis are too great to allow then to fit neatly into a few simple categories:-
 Primary metabolite (occur in all organisms)- includes Carbohydrate, amino
acids, peptide, proteins, nucleic acid and lipids etc.
 Secondary metabolite (occur only in certain organisms)- includes Steroids,
Terpenes, Alkaloids etc.
Main Classes of Natural Products
1. Terpenoids and steroids
2. Fatty acids (polyketide)
3. Alkaloids
4. Non-ribosomal (polypeptide)
5. Enzyme cofactor

5. 1. TERPENOIDS AND STEROIDS
 The compounds of the essential oil can be regarded as derived from isoprene.
 The odor of a freshly crushed mint leaf, like many plant odors, is due to the
presence in the plant of volatile C10 and C15 compounds, which are called
terpenes.
This include a vast group of substances- more than 35,000 are known derived
biosynthetically from isopentenyl diphosphate.
 Terpenoids have an immense variety of apparently unrelataed structures, while
steroids are modified terpenoids, having a common tetracyclic carbon skeleton.
These are biosynthesized from the triterpene, lanosterol.

6. 2. Alkaloids
Like terpenoids, there are a large and diverse class of compounds with more than
10,000 examples known at present.
 They contain a basic amine group in their structure and derived biosynthetically
from amino acids.
3. Fatty acids
 Fatty acids and polyketides about more than 10,000 are known are biosynthesized
from simply acyl precursors such as acetyl CoA and methyl malonyl CoA.
 Natural Products derived from fatty acid such as eicosanoid prostaglandin E1,
generally have most of the oxygen atom removed, but polyketide, such as the
antibiotic erythromycin A often have many oxygen substitutents remaining.

7. 4. Non-ribosomal polypeptide
 They are peptide like compounds that are biosynthesized from amino acids by a
multifunctional enzyme complex without direct RNA transcription.
The penicillins are good examples, but their chemistry it is bit complicated.
5. Enzyme Cofactor
Enzyme cofactor don’t fit one of the other general categories of naturla
products are usually classed separately.

8. NATURAL PRODUCTS IN MEDICINE
Name Origin (use)
Atropine (alkaloid) Atropa belladonna (opthalmics)
Cocaine (alkaloid) Erythroxylon coca ( Las, stimulant)
Noscapine (alkaloid) Papver somniferum (cough
remedy)
Caffeine Tea coffee (stimulant)
Quinine (alkaloid) Cinchona ledgeriana (antimalarial)
Digoxin (steroidal glycoside) Digitalis purpurea (heart medicne)
Heparin (carbohydrate) Liver/lung tissue of cattle
(anticoagulant)

9. ISOLATION OF NATURAL PRODUCTS

10. Plant material
Successive soxhelt extraction
with solvent A,B and C Large scale
Extract A Extract B Extract C
ACTIVE extract (s)
Bioassay In vitro
ACTIVE fraction (s)
Preliminary fractionlal by flash
chromatography /VLC/CCBioassay (in vitro)
ACTIVCE Compounds
Structure determination
(UV/IR/NMR/MS/X-Rays
Bioassay of active compounds using different
concentrations to determine the potency
In vivo assay and toxicological studies Cliniical trials Patent application
Application for approval Pharmaceutical production and marketing
An example of natural product drug discovery process (bioassay guided approach).