Transcript 1-Introduction 2009

Natural Products and Evidence
based Herbal medicines I
Department of Natural Products
and Alternative Medicine
Introduction
 Plants have universal role in the treatment of
diseases in the major systems of medicine.
 As examples: Western medicine:
 In Mesopotamia and Egypt, Unani-Islamic,
and Ayruvedic (Hindu) systems centered in
Western Asia and the Indian and those of the
Orient (China, Japan, Tibet,…etc).
 Medical information transferred by:
ORAL from generation to generation (In tropical Africa,
North & South America and Pacific countries)
Or by WRITING (e.g. the Egyptian Papyrus Ebers c. 1600
BC)
Found in Egypt in the 1870s,
the Ebers Papyrus contains
prescriptions written in
hieroglyphics for over seven
hundred remedies. This
prescription for an asthma
remedy is to be prepared as
a mixture of herbs heated on
a brick so that the sufferer
could inhale their fumes.
Georg Ebers (18371898), Papyros Ebers (Ebers Papyrus),
Leipzig, 1875
What is Pharmacognosy?
Medicinal plants involves a number of
disciplines including: commerce, botany,
horticulture, chemistry, enzymology, genetics,
quality control and pharmacology.
But Pharmacognosy is not any one of these, It
is unified of whole of them.
 Recently, monographs on crude drugs in a
modern pharmacopoeia illustrate this
multidisciplinary approach.
Accordingly, no one person can now expect to
be an expert in all of these areas.
What is Pharmacognosy?
The word "Pharmacognosy" derived
from the Greek word
"Pharmakon“ means a drug, or medicine.
"gignosco“ means to acquire knowledge of
Pharmacognosy is “an applied science that
deals with the biological, biochemical and
economic features of natural crude drugs
and their active constituents”.
What is Pharmacognosy?
Pharmacognosy is closely related to botany and
plant chemistry (originate scientific studies on medicinal plants)
From botanical side, it concerned with the
description & identification of drugs, both in whole
state & in powder & with their history, commerce,
collection, preparation and storage, which are of
fundamental importance particularly for
pharmacopoeial identification and quality control
purposes.
What is Pharmacognosy?
◘ Pharmacognosy does not include the study of
synthetic drugs.
◘ Pharmacognosy is NOT identical to Medicinal
Chemistry and/or Pharmacology but utilizes
their methods.
◘ Pharmacognosy is a study of drugs from plant
and animal kingdoms and their natural derivs.
Pharmacognosy
An applied science that deals with the biological,
biochemical and economic features of natural
crude drugs and their constituents
It is a study of drugs from plant and animal
kingdoms and their natural derivs.
E.g.: Digitalis leaf & its glycosides (digitoxin)
Rauwolfia root & its alklaoids (reserpine)
Thyroid gland & its extracted hormone
(thyroxin)
What is Pharmacognosy?
Pharmacognosy is not confined to plants BUT
also investigates biodynamic compounds in
animals, marine organisms, fungi, and microorganisms
NOTE: Natural drug constituents which
have been prepared synthetically (e.g. ephedrine,
vanillin, caffeine, codeine, menthol, penicillin) BOTH
natural and synthetic substances are considered
a definite part of pharmacognosy.
What is Pharmacognosy?
• Many species of plants containing substances of
medicinal value which have yet to be
discovered.
• Now, large numbers of plants are constantly
being screened for their possible
pharmacological values e.g. hypoglycemic, …
• Pharmacognosist with a multidisciplinary
background are able to make valuable
contributions to these rapidly developing fields
of study.
Monographs on a large number of crude
drugs, giving written descriptions, tests of
identity, purity and assays of active constituents:
British Herbal Pharmacopoeia
American Herbal Pharmacopoeia.
Chinese Herbal Pharmacopoeia (Materia medica)
WHAT DO PHARMACOGNOSISTS “DO”?
•Isolation & characterization of “active
constituents”
•Characterization of the pharmacology of crude
extracts & active constituents
•Evaluation of quality of natural medicines
•Interdisciplinary relationship with ethnobotany
& ethnopharmacology
Ethnobotany is the study of the relationship between people and plants, field includes
studying plants as medicines, alternative methods for healing, as wild foods, as
agricultural crops; modes of transportation; as clothing and in the religious ceremonies.
Ethnopharmacology is the scientific study correlating ethnic groups, their health, and how
it relates to their physical habits and methodology in creating and using medicines.
Crude Drugs
• They are vegetable or animal drugs that consist
of natural substances that have undergone only
the processes of collection and drying.
• The term natural substances refers to those
substances found in nature, SUCH AS
• Whole plants or organs of plants, e.g. leaves,
flowers, seeds, and barks,
• OR vegetable saps, extracts and secretions
• Whole animals; glands or other animal organs,
extracts, secretions; that have not had changes
made in their molecular structure (as found in nature)
Crude Drugs
Also, means any product that has not
been advanced in value or improved in
condition by grinding, chipping, crushing,
distilling, evaporating, extracting, artificial
mixing with other substance OR by any
other process or treatment beyond what is
essential to its proper packing and the
prevention of decay or deterioration
pending manufacture.
Crude drugs are used infrequently as therapeutic agents;
more often their chief principles (derivatives or extractives
which contains active constituents) are separated by various
means.
Sources of Crude Drugs:
•Plant sources, e.g. Senna, Digitalis, Datura, Cascara,
Cinchona, Clove, Opium, etc.
•Animal sources, e.g. cochineal, cantharidin, honey, cod liver
oil, musk, thyroxin, etc.
•Marine sources, e.g. sponges, red algae, agar, etc.
•Mineral sources, e.g. talc, kaolin, kieselguhr, etc.
What is a Natural Product?
A natural product is a substance obtained from
a natural source.
1. A crude drug , e.g. Senna, Cascara,
Cinchona, etc..
2. A galenical preparation of a crude drug,
e.g. extracts and tinctures, etc..
3. A pure compound, e.g. morphine,
atropine, digoxin, etc..
4. A semithynthetic product, e.g. etoposide,
teniposide, hyoscine butyl bromide etc..
Uses of Natural products:
1.As drugs for the treatment of a wide range
of diseases, e.g. morphine, atropine,
digoxin, hormones, antibiotics, etc..
2.As pharm. aids in pharm. industry, e.g.
suspending & emulsifying agents,
suppository bases, binders, excipients,
sweetening & colouring agents, etc..
Uses of Natural products:
3. In cosmetics as flavouring & colouring
4.
5.
agents, etc.
In culture media for the propagation of
M.O. in microbiology laboratories &
biotechnology.
General uses e.g. in food industries: as
dusting powders, as indicators and in
perfumery.
Classification of Medicinal Plants:
A- Alphabetical:
Either Latin or Vernacular ‫عامي‬names
may be used.
Although they are simple and suitable
for quick references, It gives no
indication of interrelationships
between drugs e.g. Pharmacopoeias.
Classification of Medicinal Plants: (cont..)
B- Taxonomic:
Based on botanical classification, drugs
are arranged according to the plants
from which they are obtained, into:
Classes, orders, families, genera
and species.
Classification of Medicinal Plants:
C- Morphological:
1. Drugs are divided into groups such as :
leaves, flowers, fruits, seeds, herbs and
entire organisms, wood, barks, rhizomes &
roots (known as organized drugs).
2. Dried lattices, extracts, gums, resins, oils,
fats and waxes (known as unorganized
drugs).
Classification of Medicinal Plants:
D- Pharmacological or therapeutic:
This involves the grouping of drugs
according to the pharmacological
action of their most important
constituents or their therapeutic uses,
e.g cardiotonic drugs.
Classification of Medicinal Plants: (cont..)
E- Chemical or Biogenetic:
Acc. To the important constituents e.g.
alkaloids, glycosides, volatile oils, etc..,
OR based on their biosynthetic pathways,.
This is a popular approach when the
teaching of pharmacognosy is
phytochemically biased.
References Containing Monographs
on Medicinal Plants:
Government is aiming to standardized of:
Quality, Efficacy and Safety of drugs in order
that the many traditional herbs meet legal
requirements of diff countries.
Pharmacopoeia is a book recognized by the government
as legal authority for standardization of drugs, e.g.
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British Herbal Pharmacopoeia, 1996.
The British Herbal Compendium Vol. 1& 2, 1993.
The United States Herbal Pharmacopoeia.
German Commission Monographs.
The Chinese Herbal Pharmacopoeia.
Monograph
• The descriptive material pertaining to any of the
drugs in the Pharmacopoeia is known as the
monograph.
• In the monograph of a crude drug, the following
information are generally covered:
English, Arabic, Latin, French names, definition,
description, special condition for collection or
prepn for the market, identity tests, tests for
adulterants, method of assay, special storage
requirements, dose , natural or biological origin.
Official and Unofficial Drugs:
 OFFICIAL DRUG is one that is listed
and described as being a definite
therapeutic agent in the pharmacopoeia.
 UNOFFICIAL DRUG is that one that
are not recognized in the pharmacopoeia
and is used as therapeutic agent.
Origin of Crude Drugs:
• The natural or biological origin:
Botanical origin is used for a plant and
Zoological origin is used for of animal.
Benefit of Botanical Origin of the
Crude Drugs
• Knowledge of the biological origin
enables one to indicate the proper
right material and precise the source .
• E.g. one year the drug is active, even
poisonous and in other cases it is
inactive, e.g. Strophanthus seeds
Benefit of Botanical Origin of the
Crude Drugs
• This is due to the fact that the drug is
gathered from any species which collectors
may find.
• If the drug is obtained from one and the
same species, the supply of the drug will be
always of the same potency, this required
authentic sample or genuine sample to
comparison.
• Nomenclature: The binomial system was
founded by the Swedish biologist Linnaeus.
• In this system,
The first name: Start with a capital letter
denotes the genus,
-Second name
denotes the species.
Carolus Linnaeus (1707- 1778)
Swedish botanist and explorer. He studied
botany at Uppsala university and explored
Swedish Lapland. He is the first to develop
principles for defining genera and species
of organisms and to create a uniform
system for naming them, binomial
nomenclature.
-Genus and species name is followed by
author’s name who first described the
species or variety.
e.g Artemisia cina Berg., Caryophyllos
aromaticus L
• Sometimes, species name is derived from
author’s name, e.g. the species of Cinchona
named after Charles Ledger, who brought its
seeds from Brazil in 1865, is known as
Cinchona Ledergiana.
•The species name is usually chosen to
indicate certain characteristics of the plant:
A. Striking characteristic of the plant:
– Cassia acutifolia (sharp pointed leaflets)
– Conium maculatum (maculate = spotted)
– Cassia angustifolia (narrow leaflets)
– Glycyrrhiza glabra (glabrous = smooth)
– Atropa belladonna (bella= beautiful, donna=lady)
– Hyoscyamus muticus (muticus = short)
– Brosma serratifolia (serrat = margin)
B. Characteristic colour:
- Piper nigrum (black)
- Digitalis purpurea (purple)
- Digitalis lutea (yellow)
- Brassica nigra (black)
- Brassica alba ( white)
C. An aromatic plant (certain aroma)
- Myristica fragrans (nice aroma)
- Caryophyllus aromaticus (refers to aroma)
D-Geographical source:
- Cinnamoum zeylanicum ( growing in Ceylon)
- Hydrastis Canadensis (growing in Canada)
- Tamarindus indica (growing in India)
- Uriginia maritima (near the coast)
E. Pharmacological activity:
- Papaver sominferum (inducing sleep)
- Lytta vesicatoriam (causing blistering)
- Strychnos nux-vomica (causing vomiting)
- Ipomoea purge (purgative action)
F. General meaning:
- Allium sativum (cultivated)
- Riticum vulgare (wild).
- Linum usitatissimum (most useful).
• The generic name may indicate certain
characters of the plant:
e.g. Atropa means fate who cuts the thread of life
Glycyrrhiza means gluco = sweet, riza = root,
Linum, Linea = thread)
Production of Crude drugs
Collection, drying and storage of drugs:
The preparation of each drug for the market depends on
its morphological nature, constituents, geographical
source and other factors.
A. Collection of Crude Drugs:
1. Effect of Time of the Year (Seasonal var.):
It has been found that active constituents in
plants vary in amount and nature throughout the
year.
- Rhubarb is collected in summer (anthranol in
wintrer→anthraquinones in summer).
- Colchicum corm: collected in spring (alkaloids).
- Hyoscyamous muticus collected in summer (alkaloids).
2. Time of the Day
- Digitalis is collected in the afternoon.
- Solanaceous leaves collected in the morning.
- Salix collected at night.
3. Stage of maturity and age:
- Clove: collected in bud form.
- Santonica fl & tea leaves: in as unexpanded flower
buds.
- Solanaceous leaves: at flowering stage.
- Pyrethrum flower: in fully expanded.
4. General factors:
- Flowers are collected in dry weather.
- Leaves are collected when plant is flowering.
- Fruits and seeds when fully mature but unripe.
- Underground organs when aerial parts die down.
- Barks in spring (when they are easily separated).
- Unorganized drugs in dry weather (not rainy).
B. Drying of Crude Drugs
Reasons of Drying:
- To decrease size and weight (facilitate packing, transport and
storage).
- Facilitate powdering.
- Prevent enzyme action, microbial growth and
degradation of active constituents.
Enzyme action
Desirable: e.g. Vanilla pods, required slow drying.
Undesirable: e.g. Digitalis leaves, required fast drying.
•Methods of drying:
1. Drying in open air:
in sun and under cover sheds
at night or during wet weather, e.g. clove, cinnamon,...
2. Artificial oven drying (Oven-drying is more rapid
than air- drying, controlled temp. and more suitable for
use in the wet weather countries. Leaves, herbs & flowers:
20-40oC, barks & roots: 40-65oC.
3. Vacuum drying: in oven, rapid and at low temp.
4. Lyophilization used for biological fluids, enzymes,
proteins and royal jelly.
C. Storage of Crude Drugs:
During storage, Drugs are affected by light,
moisture, temp., air oxygen
(physicochemical) and by fungi, bacteria,
worms, insects and mites (biological)
• Long storage is not recommended, due
to deterioration.
• Therefore, drugs should be stored in
sealed containers in cool dark places.
Evaluation of Crude Drugs
Means to identify and to determine quality,
safety and purity.
1. It has to be certain of identity of the
collected plant from proper source by
matching to authentic plant sample
2. Preparation by proper cleaning, drying and
garbling.
3. Proper preservation of cleaned, dried, pure
drug against contamination.
Evaluation of drugs involves
the following methods:
1. Organoleptic
2. Microscopic
3. Chemical
4. Physical
I- ORGANOLEPTIC EVALUATION
Organoleptic refers to evaluation by means of the organs
of sense which includes:
- The macroscopic appearance of the drug,
- Its odour and taste and the feel of the drug to the touch.
Description of the macroscopic characteristics of
a drug include:
1.
2.
3.
4.
Shape and size.
Colour and external markings
Fracture and internal colour.
Odour and taste.
II-MICROSCOPIC EVALUATION:
 The microscope is essential in the identification of
powdered drug and in the detection of the
adulterants in powdered plant OR animal drugs.
 Microscopical description of the drug in sectional
view and powdered form is listed in official
monograph .
■ Histology
refers to the character &
arrangement of the tissues in a drug.
■ Some drugs have no cellular structure (gums,
resin).
■ Some are composed of microscopic units,
such as diatoms (kieselguhr) or hairs (Lupulin,
kamala).
■ Histological studies on very thin transverse
(TS) or longitudinal (LS) sections properly
mounted in suitable stains, reagents or
mounting media.
 In the powdered drugs the cells are mostly
broken, except those with lignified walls, but the
cell contents (starch, calcium oxalate, aleurone
grains …etc) are scattered in the powder and
become very evident in the mounted specimen.
 Microscope can be used for a quantitative
microanalysis of admixed or adulterated powders.
 This study is done by counting a specific
histological feature (stomatal index, palisade ratio)
in a measured quantity of the unknown powder and
comparing the count with that obtained for the
same feature in a known standard sample.
III-CHEMICAL EVALUATION:
 Chemical tests are employed to identify crude
plant drugs.
E.g. characteristic red colour developed in
Cascara on addition of NH3 test solution.
 To ascertain the purity of certain drugs
E.g. to detect the presence of inorg. iodine in
thyroid tablets by adding a starch test solution.
III-CHEMICAL EVALUATION:
 Chemical assays are dependent on the
pharm. extractive processes with
subsequent purification of the main
constituent.
 In many drugs the chemical assays
represents the only method of
determining the official potency.
IV-PHYSICAL EVALUATION
 Typical physical constants is very rare.
 The specific gravity is used with nutgalls,
where the galls that will not sink in H2O are
considered to be of inferior quality,
 In jalap and clove, the specific gravity should
be higher than that of water.
 The elasticity of certain fibers, such as
cotton, is a physical constant of importance.
IV-PHYSICAL EVALUATION
Alkaloids aconitine (light blue), berberine
(yellow), emetine (orange).
Alkaloid quinine has blue fluroscence in
acid solution in UV or even in daylight.
The use of physical constants on active
constituents.:
Solubility, specific gravity, optical
rotation, melting point… etc
IV-PHYSICAL EVALUATION
 The response of some drugs in powdered
form or in their smooth section surface to
the UV , e.g. in detecting of adulteration of
genuine of rhubarb from rhapontic
rhubarb (blue fluroscence)

The morphological and anatomical
evaluation are not sufficient but nature or the
amount of the active substances are the most
important
 Chromatography (TLC, PC and GC) is really a
finger print technique, where the individual
substances to which the activity is due, can be
tested rapidly.