Introduction To Pharmacognosy

Prepared By
Ms. Smita V. Nhawkar
Assistant Professor
Ashokrao Mane College of Pharmacy, Peth Vadgaon
Department-Pharmacognosy

• Pharmacognosy is derived from two Greek words, Pharmakon & Gnosis
• Pharmakon – means ‘drug’
• Gnosis – means ‘knowledge’
• In brief, Pharmacognosy means ‘knowledge of drugs’.
• It is a study of drugs that originate in the plant & animal kingdoms.
• Pharmacognosy is a branch of pharmacy which deals with the basic sources
of medicines from nature (plant & animal) and their uses as medicaments
from ancient time to present day. OR
• Pharmacognosy may be defined as an important branch of Pharmacy which
deals with the study of structural, physical, chemical, biochemical and
sensory characters of natural drugs of plant and animal origin.
• Pharmacognosy is a subject in which plants parts are identified or
authenticated using macroscopical, anatomical, phytochemical characters.
Therefore Pharmacognosy may be defined as an important branch of
Pharmacy which deals with the study of structural, physical, chemical,
biochemical and sensory characters of natural drugs of plant and animal
origin. It also includes a study of their history, distribution, cultivation,
collection, identification, preparation, evaluation, preservation, use and
commerce.

History of Pharmacognosy
• The medicines were originated in Egypt and India.
• Medicines were recorded both in papyrus of Egypt around 1,500 BC and
later in Ayurveda of India.
• Hippocrates (460-370 BC) is viewed as the 'Father of medication' for his
commitment to human life structures and physiology.
• He gathered, recognized and utilized countless medicinal plants.
• Aristotle (384-322 BC), who was an understudy of incredible scholar Plato,
recorded more than 500 plants of restorative significance with their
description and uses.
• Theophrastus (370-287 BC) gathered, recognized an expansive number of
therapeutic plants and recorded their restorative properties.

• Dioscorides (first Century AD), a Greek Physician, distributed five
volumes of a book, entitled 'De Materia Medica' in 78 AD, which portrayed
more than 600 therapeutic plants with their collection, storage and uses.
• Pliny de Elder (23-70 AD), a Greek botanist, gathered and portrayed a
substantial number of restorative plants with their uses.
• Galen (131-200 AD), a Greek pharmacist physician, portrayed strategies for
planning pharmaceutical details containing plant and animal drugs.
• These techniques and his different perceptions on restorative plants have been
recorded in upwards of 20 volumes of books.
• The present day Galenica is one preparation or Galenicals are set up as per these
methods.
• Galen described the extraction method of chemical constituent from the plants.
• He created different techniques for extraction hence the branch of pharmacy
which manages extraction of chemical constituent from plants and animals is
called as Galenical Pharmacy.

• Around then, information about medicines came basically from senses
and practical experiences, and the real substance for
any restorative book were for the most part about therapeutic viability
and incompletely about its name, origin, morphology, and identifying
sensory characteristics.
• Because underdeveloped science, individuals could barely know all
the details about restorat plants.

Pharmacognosy in Early Modern Times(1815-1930)
• In 1815, C.A. Seydler, a German scientist who utilized "pharmakognosie"
in his book named Analecta Pharmacognostica, was referred to as the
father of pharmacognosy.
• In 1825, Martius, a German researcher, set up "pharmakognosie" as a
subject to study in college, and afterwards another discipline named
pharmakognosie developed in natural science.
• As indicated by Martius, pharmacognosy, as a part of merchandizing, was
a review to research drug base taken from nature to test its virtue and to
check debasements or adulterants.

• From that point on, German researchers distributed works, named
pharmakognosie, on plant and animal drugs progressively.
• In 1880, Gendo Di, Japanese researcher, translated pharmakognosie as
pharmacognosy.
• In 1806, Serturner, a German scientist, described the cell to be the
fundamental unit of plant structure, and after that microscopes were
utilized to research about the inner structure of crude drugs.
• In 1857, Schleiden distributed a book named Grundriss der
Pharmakognosie des Pflanzenreiches (establishment of
pharmacognosy of plants), in which he gave a detailed depiction of
microstructure of a considerable number of medicinal plants.

• Afterwards, Berg in 1865 and Vogl in 1887 distributed anatomical map of
crude drugs progressively, which assisted the advancement of
distinguishing crude drugs by the utilization of microscope, and afterwards
this strategy turned into the most critical one to recognize crude drugs

Modern Time Pharmacognosy (1930 to the Late 1990s)
• The development of modern Pharmacognosy began during the period of 1930-1960 by
the application of a broad spectrum of biological and scientific subjects, including
botany, ethno botany, medical anthropology, marine biology, microbiology, herbal
medicine chemistry, biotechnology, Phytochemistry, pharmacology, pharmaceutics,
clinical pharmacy and pharmacy practice along with modern analytical techniques like
paper and thin layer chromatography (TLC),
gas chromatography (GC),
High performance liquid chromatography (HPLC),
Extreme and ultra-pressure liquid chromatography (XLC, UPLC),
high pressure thin layer chromatography (HPTLC),
Mass spectroscopy,
Liquid chromatography combined with mass spectroscopy (LC/ MS),
High Resolution Mass Spectroscopy (HRMS)

During this period isolation, structure elucidation and various pharmacological activity
of different Phytoconstituents were studied examples like isolation of penicillin in 1928
by Alexander Fleming from microorganisms and later on commercial production of the
same in 1941 by Florey and Chain.
Gradually, other antibiotics were isolated and their chemistry was studied and among
them streptomycin, chloramphenicol, tetracycline are most important.
Some of the important isolated constituents are-
Reserpine from Rauwolfia root (responsible for anti-hypertension action)
Vincristine and vinblastine from vinca plant (responsible for treatment of leukemia)
Digitoxin from digitalis plant (only one potent cardiac drug which is used directly as
an allopathic medicine)

Morphine (a potent analgesic) and codeine (a potent antitussive)
isolated from dried latex of Opium poppy plant
Ergotamine from ergot (have potent oxytocic activity) etc.
Several steroidal hormones were also isolated from plants. e.g.
progesterone from diosgenin (from dioscorea plants)

• Gradually biosynthetic pathways were also identified for synthesis of
primary and secondary metabolites.
• Some of the important pathways are
Calvin's cycle for photosynthesis (biosynthesis of carbohydrate, a
primary metabolite),
Shikimic acid pathway for synthesis of aromatic compounds,
Acetate pathway for anthracene glycoside synthesis,
Isoprenoid pathway for synthesis of terpenes and steroids etc.
• Development of structure activity relationship(SAR) of the
phytoconstituents helped in the identification of the structure of the
constituents, as well as effects of addition or deletion of the organic or
inorganic groups in the mother structure.

• For example, hypotensive and tranquillizing actions of reserpine are
attributed to the trimethoxy benzoic acid moiety, which is essential;
• presence of lactone Ring more essential for the action of cardiac
glycosides;
• oxytocic activity of methyl ergometrine in ergometrine in Ergot
• 9:10 position hydrogenation in ergotamine suppressed oxytocic activity
that of increases spasmolytic activity.
• Similarly, etoposide, a semi synthetic derivative of podophyllotoxin
(isolated from podophyllum plant), has more potent anticancer activity.

Applications of Pharmacognosy
1. Plant Bioactive extraction and isolation:
• The extraction of plant material and isolation of plant constituents typically
require tedious protocols that are essential for isolating biologically active
compounds and understanding their role in disease prevention and
treatment.
• Bioactives isolated from leaf, stem, root, bark, flower, fruit, seed or other
plant materials are often identified using a Bioassay process.
• This type of approach is useful for the investigation of alkaloids,
antioxidants, bioflavonoids, terpenoids.

2. Development of plant biomarkers:
• DNA fingerprinting is the technique based on the use of polymerase chain reaction
(PCR), to reveal the specific DNA profile of a particular organism which is as
unique as a fingerprint.
• DNA fingerprinting can distinguish plants from different families, genera, species,
cultivars and even sibling plants.
• Chromatographic techniques such as High Performance Thin-Layer
Chromatography and High Performance Liquid Chromatography find various
secondary metabolites of a plant.
• Combining use of DNA fingerprinting and chemical fingerprinting will be an
effective tool in authentication and quality control of herbs.
• Some examples of biomarkers are: (a) Curcumin isolated from Curcuma longa
rhizome which is recently under clinical trial for curing head and neck squamous
cell carcinoma. (b) Withanolide-D isolated from Withania somnifera roots, the
recent clinical trial projected that it induces apoptosis in leukemia. (c) Kutkoside
isolated from Picrorhiza kurroa, the recent clinical trial established as a serum
biomarkers for liver cirrhosis.

3. Development of nano fertilizers and nano medicines:
• Nanotechnology in drug delivery is exemplified by nanocrystals,
liposomes, nanoparticle-protein conjugates, magnetic nanoparticles,
nanogels and biodegradable nanoparticles.
• Fertilizer particles can be coated with nano membranes that facilitate
slow and steady release of nutrients thereby reducing loss of nutrients
and enhancing its use efficiency of medicinal plants.
• Recent study revealed the use of nanotechnology in in-vitro and in
vivo drug and gene delivery. With the incorporation of this innovative
technology, the safety, quality, and freshness of food can be assured,
which will lead the nanotechnology being the key technology for
developing health food.

• In herbals, there are already preliminary results obtained from trials
with turmeric, black pepper, berberine, triphala using nano
formulations and more that give strong evidence to prove the concept
of improved efficacy in reduction in these herbal preparations.
• Recently, Stevioside nano-bioconjugated on PEG-PLA nanoparticles
of size 150-170 nm showed the initial burst phase followed by the
slow controlled release of 2 hours and 21 days respectively which
helped in the development of antidiabetic nanomedicine.
• The coating induces the plants to swallow the particles, effectively
inserted genes inside the plant cell walls.
• The coating induces the plants to swallow the particles, effectively
inserted genes inside the plant cell walls. The biologists have
succeeded in using this technology to introduce DNA into tobacco and
corn plant, among others.

4. Nutraceuticals towards biochemical mechanisms of healthy
aging:
• Neutraceutical are a group of natural substances that include
certain herbs and products cholesterol-lowering margarines,
psyllium-fortified products as dietary supplements.
• Some herbs like ginseng, ginkgo, nuts, grains, tomato, soy
phytoestrogens, curcumin, .melatonine, vitamins, etc. can prevent
diseases.
• Phytosterols herbal antioxidant and natural sweeteners are the
substances that successfully act as functional foods.
• Stevia leaves, brazzein , curculin etc. are the recent focus for
sugar supplement and use as natural non caloric sweetners.

• Cassia twigs, liquorice root, sealwort are used in nanotechnology to
reduce their active ingredients to smaller sizes, thus enabling them to
enter cancerous cells without damaging healthy cells.

Scope of Pharmacognosy
• 1. ISOLATION OF PHYTOCHEMICALS
• Glycosides from digitalis leaves
• Alkaloids from the plants of Belladonna, Hyocyamus, Rauwlofia
• Morphine and other alkaloids from the plant opium
2. STRUCTURE ACTIVITY RELATIONSHIP
• Tubocurarine and Toxiferine from curare plant have muscle relaxant
properties because of quaternary ammonium groups.
• The hypotensive and tranquillizing actions of reserpine are due to the
trimethoxy benzoic acid.

3. DRUGS OBTAINED BY PARTIAL SYNTHESIS OF NATURAL PRODUCTS
Preparation of Steroid hormones from diosgenin by acetolysis and oxidation and
further preparation of cortisone by microbial reactions.
4. NATURAL PRODUCTS AS MODELS FOR SYNTHESIS OF NEW DRUGS
Morphine is the model of a large group of potent drugs
• Cocaine for local anaesthetics
• Atropine for certain spasmolytic.
5. DRUGS OF DIRECT THERAPEUTIC USES
• antibiotics, steroids, ergot alkaloids, vincristine, etc
6. BIOSYNTHETIC PATHWAYS INVESTIGATION
• Biosynthetic pathways of primary and secondary metabolites
7.CULTIVATION AND COLLECTION OF MEDICINAL PLANTS
clove, cinchona , cinnamon, senna, opium, etc

 Sources of Drugs
Drugs are obtained from six major sources:
•Plant sources
•Animal sources
• Marine sources
•Mineral/ Earth sources
•Microbiological sources
•Semi synthetic sources/ Synthetic sources
•Recombinant DNA technology

1.Plant Sources:
• Plant source is the oldest source of drugs.
• Most of the drugs in ancient times were derived from plants.
• Almost all parts of the plants are used i.e. leaves, stem, bark, fruits and
roots.
1. Leaves:
a. The leaves of Digitalis Purpurea are the source of Digitoxin and
Digoxin, which are cardiac glycosides.
b. Leaves of Eucalyptus give oil of Eucalyptus, which is important
component of cold & cough syrup.
c. Tobacco leaves give nicotine.
d. Atropa belladonna gives atropine.

2. Flowers:
•Poppy papaver somniferum gives morphine (opoid)
•Vinca rosea gives vincristine and vinblastine
•Rose gives rose water used as tonic.
3. Fruits:
• Senna pod gives anthracine, which is a purgative.
• Calabar beans Give physostigmine, which is cholinomimetic agent.
4. Seeds:
• Seeds of Nux Vomica give strychnine, which is a CNS stimulant.
• Castor seeds give castor oil.
• Calabar beans give Physostigmine, which is a cholinomimetic drug

5.Roots:
• Ipecacuanha root gives Emetine, used to induce vomiting as in
accidental poisoning. It also has amoebicidal properties.
•Rauwolfia serpentina gives reserpine, a hypotensive agent.
•Reserpine was used for hypertension treatment.
6.Bark:
•Cinchona bark gives quinine and quinidine, which are antimalarial
drugs. Quinidine also has antiarrythmic properties.
• Atropa belladonna gives atropine, which is anticholinergic.
• Hyoscyamus Niger gives Hyosine, which is also anticholinergic.
7.Stem:
• Chondrodendron tomentosum gives tuboqurarine, which is skeletal
muscle relaxant used in general anesthesia.

2.Animal sources
• Pancreas is a source of Insulin, used in treatment of Diabetes.
• Urine of pregnant women gives human chorionic gonadotropin (HCG) used
for the treatment of infertility.
• Sheep thyroid is a source of thyroxin, used in hypertension.
•Cod liver is used as a source of vitamin A and D.
• Anterior pituitary is a source of pituitary gonadotropins, used in treatment
of infertility.
• Blood of animals is used in preparation of vaccines.
• Stomach tissue contains pepsin and trypsin, which are digestive juices used
in treatment of peptic diseases in the past. Nowadays better drugs have
replaced them.

3.Marine sources
• There are more than 5 lakhs species of marine organisms available in
seas and ocean.
• They are used for many important therapeutic activities.
• The enormous ecological resources of the sea and ocean have been
exploited since ancient times and the use of marine animals used as the
sources of medicine.
• Oceans contain more than 80 per of diverse plant and animal species.
• Such organisms like sponges, tunicates, fishes, soft corals are sources
of bioactive.

The drug that are produced from the marine sources are listed in table
Organism Compound
Ascidian Aplidine
Bryozoan(moss animal) Bryostatin-I
Mollusk Kahalalide F
Sea Hare Aplyronine
Yellow sponge Agosterol A
Tube worm Cephalostatin

4.Mineral Sources
Metallic and Non metallic sources:
• Iron is used in treatment of iron deficiency anemia.
• Mercurial salts are used in Syphilis(bacterial inf.).
• Zinc is used as zinc supplement.
• Zinc oxide paste is used in wounds and in eczema.
• Iodine is antiseptic.
• Iodine supplements are also used.
• Gold salts are used in the treatment of rheumatoid arthritis.

Miscellaneous Sources:
•Fluorine has antiseptic properties.
•Borax has antiseptic properties as well.
•Selenium as selenium sulphide is used in anti dandruff shampoos.
•Petroleum is used in preparation of liquid paraffin.

5.Synthetic/Semisynthetic sources
Synthetic Sources:
• When the nucleus of the drug from natural source as well as its
chemical structure is altered, we call it synthetic.
• Examples include Emetine Bismuth Iodide
Semi Synthetic Source:
• When the nucleus of drug obtained from natural source is retained but
the chemical structure is altered, we call it semi-synthetic.
• Examples include Apomorphine, Diacetyl morphine, Ethinyl
Estradiol, Homatropine, Ampicillin and Methyl testosterone.
• Most of the drugs used nowadays (such as antianxiety drugs, anti
convulsants) are semisynthetic forms

6. Microbiological Sources:
• Penicillium Notatum is a fungus which gives penicillin.
• Actinobacteria give Streptomycin.
• Aminoglycosides such as gentamicin and tobramycin are obtained
from Streptomyces and micro-monosporas

7. Recombinant DNA technology:
• Recombinant DNA technology involves cleavage of DNA by enzyme
restriction endonucleases.
• The desired gene is coupled to rapidly replicating DNA (viral,
bacterial or plasmid).
• The new genetic combination is inserted into the bacterial
cultures which allow production of vast amount of genetic material.
Advantages:
• Huge amounts of drugs can be produced.
• Drug can be obtained in pure form.
• It is less antigenic. (induce immune system)

Disadvantages:
• Well equipped lab is required.
• Highly trained staff is required.
• It is a complex and complicated technique

7.Plant Tissue Culture
• It is an in-vitro cultivation of plant cells, tissues and organs in liquid or
semi-solid nutrient media under aseptic and controlled environment.
• In this method primary and secondary plant metabolites are regenerates.
• The basic criteria for plant tissue culture are totipotency and plasticity.
• Totipotency is defined as regeneration capacity of the selected plant parts
whereas plasticity is the withstand capacity of plants in any stressful
condition.
• The plant tissue culture technique is important because isolation of
bioactive compounds from the medium is very easy, rare and endangered
plant species are micropropagated and cultivated in mass scale, production
of immobilized plant cell for future use and even biochemical conversion
is easy etc.

Applications:
• Mass scale production of plants.
• Conservation of endangered plant species.
• Cultivation of disease resistance plants.
• Production of micropropagated plants.

Advantages:
• Some plants, which do not multiply by seeds, can be propagated
through plant tissue culture technique.
• More amounts of secondary metabolites are produced.
• Large number of plants can be produced in a short time.
• Chemicals which are used in the tissue culture increase the capacity of
produced plants to resist with biocidal chemicals, environment stress
and competitive to survive over weed.
• Isolation of constituents from plant is easy.
• Mass propagation of plants is easy

Organized Drugs and Unorganized Drugs
Crude drugs are broadly divided into the two main groups on the basis
of their apparent morphological forms of cellular and structural
organization.
1. Organized crude drugs
2. Unorganized crude drugs
1. Organized crude drugs- If the drugs are procured from cellular parts
of plants in raw form is know as organized crude drugs.
2. Unorganized crude drugs- If the drugs that are procured from non-
cellular parts of plants are known as unorganized crude drugs.

Classification of crude drugs
• Crude drug i. e Simple drug
• Crude drugs are plant, animal or their parts which after collection are
subjected only to drying or making them into transverse/ longitudinal
slices pieces or peeling them in some cases.
• They exist in natural form.
• Crude drugs may be derived from various natural sources like plants,
animals, minerals and microorganisms etc.

• Because of their wide distribution the arrangement of classification in
a definite sequence is necessary to understand easily.
• Although each system of classification has its own merits and
demerits, but for the purpose of study the drugs are classified in the
following different ways:
1. Alphabetical classification
2. Morphological classification
3. Taxonomical classification
4. Pharmacological classification
5. Chemical classification
6. Chemo-taxonomical classification

1. Alphabetical classification
• The crude drugs are arranged according to the alphabetical order/form
of their Latin and English names.
• Some of the Pharmacopoeias and reference books which classify crude
drugs according to this system are as follows.
1) Indian Pharmacopoeia (IP) 1955 (Latin)
2) Indian Pharmacopoeia (IP) 1966 (English)
3) British Pharmacopoeia (BP) (English)
4) British Pharmacopoeia Codex (BPC) (English)
5) United States of Pharmacopoeia (USP) (English)
6) European Pharmacopoeia (Latin)

• In Indian Pharmacopoeia 1966 names changed to English like
Amylum changed to starch
Acacia changed to Indian gum
Advantages:
1. It is simple method, in this system location, tracing and addition of
the drug is easy.
2. No technical person is required for handling the system.
Disadvantages:
1. Scientific nature of the drug cannot be identified by this method,
whether they are organised or unorganised drug.
2. This system does not help in distinguishing the drugs of plant,
animal and mineral source. (Original source is not clear)

Examples:
Acacia, Agar, Benzoin, Beeswax, Cinchona, Cinnamon, Digitalis,
Datura, Ephedra, Fennel, Ginger, Isapagol, Jalap, Kino, Linseed,
Mustard, Nutmeg, etc.

2. Morphological classification:
• The crude drugs are arranged (Grouped) according to the part of the
plant or animal represented into organised (Cellular) drugs and
unorganised ( Acellular ) drugs.
Organized (Cellular):
• Drugs are the direct parts of the plant and are divided into leaves,
barks, wood, root, rhizome, seed, fruit, flower, stem, hair and fibers.
Unorganized ( Acellular):
• Drugs are the products of plant, animal and mineral source and they
are divided into
Dried latex,
Dried juice,
Dried extracts,

Gums,
Resins,
Fixed oils and fats,
Waxes,
Volatile oil,
Animal products,
Minerals (Solids, liquids, semi solids etc).

Plant parts Drugs
Roots Rauwolfia, Liquorice, Ipecac
Rhizomes Ginger, Podophyllum, Turmeric
Flowers Clove, Saffron, Pyrethrum
Seeds Nux vomica, Linseed, Isapgol
Fruits Fennel, Coriander, Dill
Stems Ephedra
Hair and Fibres Cotton, Hemp, Jute
Organised drugs (Plant) (Cellular drugs)

Plant, animal, Mineral Drugs
Dried latex Opium, Papain
Dried Juice Aloe, Kino
Dried extracts Agar, Catechu, Pectin
Gums Acacia, Tragacanth, Stericulia
Resins Benzoin, Colophony, Asafoetida
Fixed oils and fats Castor , Chaulmoogra, Cotton seed
Waxes Beeswax, Spermaceti
Volatile oils Coriander, Cinnamon, Clove

Plant, animal, Mineral Drugs
Animal products Bees wax, Shark liver oil,
Gelatin
Minerals Bentonite, Kaolin, Talc
Unorganised drugs (Acellular drugs)

Advantages
1. This system of classification is more convenient for practical study
especially when the chemical nature of the drug is not clearly understood.
2. This type of classification is very useful in identifying the adulterants
used.
Disadvantages:
1. It does not give an idea about biological source, chemical constituents and
uses.
2. When different parts of the plant contain different chemical constituents, it
is difficult to classify them.

3. Chemical classifications of crude drugs
The crude drugs are divided into different groups according to the chemical
nature of their most important constituent present in the drug to which the
pharmacological/therapeutic activity of drug is attributed.
Chemical constituents Drugs
Alkaloid Datura, Vasaka, Vinca, Lobelia
Glycoside Cascara, Senna, Digitalis
Tannins Catechu, Myrobalan, Ashoka
Volatile oil Clove, Eucalyptus, Cinnamon
Lipids Castor oil, Beeswax, Arachis oil
Carbohydrates and derived
products
Acacia, Agar, Honey, linseed
Resin Colophony, Benzoin
Vitamins & hormones Yeast, Shark liver oil, Insulin

Advantages :
1. Chemical constituents are known,
2. Medicinal uses are known
Disadvantages :
1. Drugs of different origin are grouped under similar chemical titles.
2. This type of classification makes no proper placement of drugs
containing two different types of chemicals.
3. Eg: Certain drugs are found to contain alkaloids and glycosides
(Cinchona),
Fixed oil and volatile oil (Nutmeg) of equal importance together and
hence it is difficult to categorize them properly

• In this system the drug are arranged according to taxonomical studies.
• The drugs are arranged according to their phylum, order, family,
genus and species.
• It is purely a type of botanical classification or biological classification
and restricted mainly to crude drugs from plant source.
Advantages:
• Easy for the classification of crude drugs
Disadvantages:
• The system is criticized for its failure to recognize the organised /
unorganized nature of crude drugs in their morphological studies.
4. Taxonomical classification of crude drugs

• The drugs obtained from plants having alternate leaves, flowers, seeds,
capsules (Hyocyamus, Datura, Bellodonna, Stromonium) are
considered with other members of solanaceae.
• The system fails to face into an account chemical nature of active
constituent and therapeutic significance of crude drugs.

5. Pharmacological classification of crude drugs:
• Here, the crude drugs are grouped according to pharmacological action
(Therapeutic action) of their chief active constituent (most important) or
therapeutic uses.
• In this system, all the cathartic drugs are brought together regardless of their
morphology, taxonomy or chemical relationship. Thus, Podophyllum (a
rhizome), Jalap (a tuberous root), Cascara (a bark) and Castor oil (oil) are
considered at the same time when this system is used.
Drugs acting on GIT:
Type of Action Example of Drugs
Bitters Gentian, Quassia, Cinchona
Carminatives Dill, Mentha, Cardamom
Emetics Ipecacuanha
Anti-amoebiasis Kurchi, Ipecauanha

Bulk laxatives Agar, Isapghula, Banana
Purgatives Senna, Castor oil
Peptic ulcer Derivatives of Glycyrrhitinic acid
treatment
(Liqourice and Raw banana)
Drugs acting on respiratory system:
Expectorant -Liqourice, Ipecacuanha, Vasaka
Anti-tussives - (Codeine, Noscapine)
Bronchodilators -Ephedra, Tea (Theophylline)
Drugs acting on CVS:
Cardiotonics -Digitalis, Squill, Strophanthus
Cardiac depressants - Cinchona (quinidine), Veratrum
Vaso-constrictors - Ergot (ergotamine), Ephedra

• Anti-spasmodics:
Smooth Muscle Relaxants - Opium, Datura, Hyoscyamus
Skeletal Muscle Relaxants – Curare
Anti-cancer: Vinca, Podophyllum, Taxus, Camptotheca
Anti-rheumatics: Aconite, Colchicum, Guggul
Astringents: Myrobalan, Black Catechu

Advantages
• The special advantage is that if even chemical constituents of the crude drugs
are not known they can be classified properly on the basis of therapeutic or
pharmacological uses.
Disadvantages
• Regardless of morphology, taxonomical status or chemical nature, the drugs
are grouped together, provided they exhibit similar pharmacological uses.
Eg: Senna, Castor oil, Jalap, are grouped together as purgatives/laxatives
because of their common pharmacological action.

6. Chemo- taxonomical classification of crude
drugs
• In this system of classification, the equal importance is given for taxonomical
status and chemical constituents.
• There are certain types of chemical constituents which are characteristics of
certain classes of plants.
• Eg: Tropane alkaloids generally occur in most of the members of Solanaceae
• Eg: Volatile oils occur in the members of Umbelliferae and Rutaceae.

Quality control of drugs of Natural Origin
• QUALITY CONTROL (QC) - Quality control (QC) is a procedure or set of
procedures intended to ensure that a manufactured product or performed
service adheres to a defined set of quality criteria
• QA is defined as a procedure or set of procedures intended to ensure that a
product or service under development (before work is complete, as opposed to
afterwards) meets specified requirements.
• QA is sometimes expressed together with QC as a single expression, quality
assurance and control (QA/QC).

• Quality control for efficacy and safety of herbal products is of importance.
• Quality can be defined as the status of a drug that is determined by identity,
purity, content, and other chemical, physical, or biological properties, or by the
manufacturing processes.
• Quality control is a term that refers to processes involved in maintaining the
quality and validity of a manufactured product.
• The term “herbal drugs” denotes plants or plant parts that have been converted
into phytopharmaceuticals by means of simple processes involving harvesting,
drying, and storage.
• In general, quality control is based on three important pharmacopoeial
definitions:

1. Identity: Is the herb the one it should be?
2. Purity: Are there contaminants, e.g., in the form of other herbs which
should not be there?
3. Content or assay: Is the content of active constituents within the defined
limits?

Identity- Identity can be achieved by macro- and microscopical
examinations. Voucher specimens are reliable reference
sources. Outbreaks of diseases among plants may result in
changes to the physical appearance of the plant and lead to
incorrect identification. At times an incorrect botanical quality
with respect to the labeling can be a problem. For example, in
the 1990s, a South American product labeled as “Paraguay
Tea” was associated with an outbreak of anticholinergic
poisoning in New York. Subsequent chemical analysis revealed
the presence of a class of constituents that was different from
the metabolites normally found in the plant from which
Paraguay tea is made.

• Purity- Purity is closely linked with the safe use of drugs and deals
with factors such ash values, contaminants (e.g. foreign matter in the
form of other herbs), and heavy metals. However, due to the
application of improved analytical methods, modern purity evaluation
also includes microbial contamination, toxins, radioactivity, and
pesticide residues. Analytical methods such as photometric analysis,
thin layer chromatography (TLC), high performance liquid
chromatography (HPLC), and gas chromatography (GC) can be
employed in order to establish the constant composition of herbal
preparations.

• Content or assay- Content or assay is the most difficult area
of quality control to perform, since in most herbal drugs the
active constituents are not known. Sometimes markers can be
used. In all other cases, where no active constituent or marker
can be defined for the herbal drug, the percentage extractable
matter with a solvent may be used as a form of assay, an
approach often seen in pharmacopeias. The choice of the
extracting solvent depends on the nature of the compounds
involved, and might be deduced from the traditional uses

• QUALITY CONTROL METHODS FOR HERBAL DRUGS or
DRUG EVALUATION
Drug evaluation means confirmation of its identity, determination of its purity
& quality and detection of nature of adulteration.
The evaluation of crude drugs is essential due to several reasons
(i) there may be substitution or adulteration because of carelessness or
intentional
(ii) biochemical variations in the crude drug
(iii) deterioration due to treatment or storage of crude drugs.

The different methods used in the standardization of crude drugs are
mentioned below/ Herbal drug evaluation methods.
• Morphological or Organoleptic Evaluation
• Microscopic Evaluation
• Chemical Evaluation
• Physical Evaluation
• Biological Evaluation

• MORPHOLOGICAL OR ORGANOLEPTIC EVALUATION
It is a technique of qualitative evaluation in which drugs are evaluated by means
organs of sense.
Organoleptic evaluation refers to the evaluation of drug through gross morphology
and other sensory characters such as color, odour, taste, touch and texture
Study of gross morphology
The drugs are arranged in various morphological groups such as leaves, flowers,
barks, seeds, fruits, woods etc. For every morphological group a systematic
evaluation can be carried out
• Leaves- Leaves are the flattened lateral outgrowth of stem.
• Leaves are of two types viz simple and compound leaves.

• A simple leaf bears bud in its axil and it is generally without incisions except
in the basal regions in some plants whereas
• compound leaf has many leaflets in the axils of which buds do not arise and
the whole leaf is divided by incisions in many segments which arise on a
common rachis.
• Types of Leaves –
Simple leaf
Compound leaf
• There are different shapes and sizes of the leaves. The different shapes of
leaves, their apex, margin, base, and venation are helpful in identification of
drugs.

• flowers- A flower is a modified shoot meant for production of seeds and it is
built up on the enlarged end of stem called as thalamus. It consist of four basic
parts i.e the calyx, corolla, androecium and gynoecium. The bunch of flowers is
called inflorescence.
• Bark- Due to the continuous formation of cork, cork cambium etc. and
production of secondary tissue, the cork cambium layers are pressurized and
move towards outside.
• In such condition these cells do not get nutrients and become dead and the
layers formed by cells is known as bark.
• Barks are collected from branches and trunks of the trees and obtained in the
form of strips.
• The shape of bark varies and it depends upon the type of incision given at the
time of collection

• Fruits- Fruits are defined as the matured ovary with or without associated parts.
• Fruits are classified into three main groups viz (i) Simple fruits
(ii) Aggregate fruits (iii) Multiple or Composite fruits.
• A simple fruit is that which develops from a single ovary of single flower with or
with-out other parts.
• They are categorized into two main groups viz dehiscent and indehiscent.
• Aggregate fruits are developed from polycarpellary apocarpus ovary. Each carpel
forms a single fruitlet.
• All the fruitlets arise from a single flower and are attached on the same axis
therefore termed as aggregate fruits.
• Composite fruits are developed from the inflorescence.
• The peduncle, perianth or calyx and corolla as well as ovular parts after maturity
and ripening forms a fleshy fruit.
• The shape of fruits may be oblong, ellipsoidal and globular.

• The example of fruit drugs are fennel, coriander, cardamom, dill, etc.
Seeds-
• A seed is a fertilized ovule.
• It consist of three parts viz. seed coat, embryo and endosperm.
• Seeds are characterized by the hilum, a point of attachment of seed to stalk, a
minute opening for the absorption of water and the raphe, a longitudinal
marking of adherent stalk.
• The examples of seed drugs are nux vomica, isapghula, castor, mustard,
linseed etc

• Subterranean organs-
These includes underground structures like
(i) root (n) stem modifications such as bulb (garlic, scilla ),
(ii) corm (colchicum)
(iii) tubers (aconite) and rhizomes.
Root grow downward into the soil and they do not have bud and well marked
pith.
Example of root drugs are ipecac, aconite, rauwolfia, jalap, senega etc.
Rhizomes are thick, fleshy and characterized by the presence of buds and
scale leaves. They grow horizontally under the soil.

• Examples of rhizome drugs are ginger, rhubarb, turmeric, podophyllum,
valerian etc
• The underground structures are characterized by the absence of chlorophyll and
where, starch is present it is usually abundant and in the form of large grains of
reserve starch.
• They are often swollen and in the preparation for the market they are dried and
cut into small pieces.

MICROSCOPIC EVALUATION
• This method gives a detail microscopic examination of organized crude drug in
their entire and powdered forms.
• A very thin section of the drugs are prepared and histological studies are
performed.
• The various characteristics of cell walls, cell contents, starch grains, lignin,
calcium oxalate crystals, fibres, vessels and trichomes can be studied.
• The various stains and reagents are used to study the different cellular structure.
• This method is also helpful in studying the constituents by application of
chemical methods to histological sections of drugs or to the drugs in powdered
form.
• For example, mucilage is stained to pink with ruthenium red and starch and
hemicellulose is stained blue with N 50 iodine solution.

Trichomes-
• Trichomes are the tubular or glandular out-growth of the epidermal cell and are
known as plant hairs.
• They are present on the aerial parts of the plant but are absent on the roots.
• Trichomes are present in various parts of plant such as leaves(Datura, fruits(
Ladies finger), seeds( Strophanthus) etc.
• Trichomes performs various functions.
• They excrete water in some plants like Mentha piperita
• they excrete volatile oil.
• The hairs of tobacco and plumbago plants produce a kind of gummy material.
Therefore trichomes are important diagnostic characters for the identification of
drugs

• Trichomes are classified below on the basis of structure and number of cells present
in them:-
1. Non Glandular Or Clothing Trichomes
2. Glandular Trichomes
A.Non Glandular Or Clothing Trichomes-
Clothing trichomes are of two types
1- Unicellular Trichomes :- These trichomes vary from small papillose outgrowth to
large robust structure.
Linear, thick walled and warty trichomes – Damiana
Linear, strongly waved, thick walled trichomes- Yerba santa
Large, conical, longitudinally striated trichomes - Lobelia
Long, tubular, flattened, and twisted trichomes - Cotton
Lignified trichomes – Nux vomica, Strophanthus
Short, conical trichomes - Tea
Short, conical, warty trichomes - Senna
Short, sharp, pointed, curved, conical trichomes - Cannabis

2- Multicellular trichomes :-
These trichomes are of two types :-
(A)Multicellular unbranched trichomes :-
Uniserate
(i) Bi-cellular, conical - Datura
(ii) Three celled long - Stramonium
(iii)Three to four celled long - Digitalis
(iv) Four to five celled long - Belladonna
Biserate - These type of trichomes are found in Calendula officinalis.
Multiserate - Multiserate trichomes are found in Ettphorbia pilulifera and male
fern.

(B) Multicellular branched trichomes :- It is of four types
Stellate :- These are found in hamamelis and altheae leaves.
Peltate (Shield like structure) :- These are found on leaves of Eleagnus and on the
leaves and young twigs of Croton eleuteria.
Candelabra ( Uniserate branched axis) :- These can be found in Verbascum
thapsus and

Glandular trichomes
These trichomes have glandular cell at the apex.
They are classified as
1- Unicellular glandular trichomes :- They do not posses stalk for eg. Piper
betel and vasaka.
2- Multicellular glandular trichomes :- Most of the glandular trichomes are
multicellular.
• Uniseriate stalk with single spherical secreting cell at the apex - Digitalis
purpurea.
• Uniseriate multicellular stalk with single spherical cell at the apex - Digitalis
thapsi and belladonna Unicellular stalk and a bicellular head - Digitalis
purpurea
• Uniseriate stalk and multicellular head - Hyoscyamus
• Biseriate stalk and biseriate secreting head - Santonica and plants of
Compositae

• Short Stalk and secreting head formed of a rosette of club -shaped cells -
Mentha species
• Multiseriate cylindrical stalk and a capitate rosette of secreting cells -
Cannabis

Microscopic Evaluation
• This evaluation is also known as anatomical evaluation or histological
evaluation of crude drugs.
• This method can be used to identify the organized drug in powdered
form by their histological characters or anatomical cell or tissue
arrangements.
• Various reagents (like chloral hydrate, conc. HCl, glycerin) and stains
(phuloroglucinol for identification of lignified cells and tissues like
xylem, phloem etc., Iodine for detection of starch grains etc.) can be
used to differentiate cellular structure.
• This evaluation also covers study of the constituents by application of
chemical method to small quantities of powdered drug. This is known
as chemomicroscopy.

• The elements such as stomata, trichomes, vessels, fibres, stone cells, starch
grains, medullary rays, oil cells, calcium oxalate crystals are present in
powdered condition and are used in microscopic identification of crude drugs.
• For example, leaves contain epidermis cells included trichome, stomata,
calcium oxalate crystals (if present); bark contains phloem elements
(cinchona), stone cells (Kurchi) or sometimes both (cascara); trichome
(nuxvomica); fruits contain oil cells, endosperm, pericarp, epicarp, mesocarp
etc.
• This evaluation method is also useful in identification of closely related drugs
or species. Hence microscopy is two types viz.
• Qualitative
• Quantitative.

• Qualitative microscopy is only detection and identification of cellular
structures of drugs whereas
• Quantitative microscopy is to determine particular cellular substances like
linear measurement as diameter of
• starch grains,
• length of fibres, vessels,
• quantitative microscopic constant as stomatal index,
• vein islet number,
• palisade ratio,
• Lycopodium spore method etc. using camera lucida method using two types
of micrometers viz. Stage and eye piece micrometers

Stage micrometer-
• Each big division of stage micrometer is total 1.0 mm in length.
• It has 100 divisions. Each division is 1/100 = 0.01 mm.
Eyepiece micrometer-
• It is a circle of glass with a scale etched on the surface.
• It is a scale of 1 mm length with 100 divisions.
Calibration:
• Both the eyepiece and stage micrometers are kept in their respective position
and coincided with any line of eyepiece and any line of stage micrometer.
• Thereafter the number of lines counted which are coincide further.
• Then the divisions of eyepiece and those of stage micrometer present
between the two coincided lines are counted.

Calculation:
• Now, if 7 division of eyepiece coincided with 4 division of stage micrometer,
• Then the value of one division of eyepiece micrometer is calculated as: 1
division of stage micrometer = 0.01 mm = 10 µ
• Therefore, 4 division of stage = 10 × 4 = 40 µ Now,
• 7 division of eyepiece = 4 division of stage = 40 µ Hence,
• 1 division of eyepiece = 40/7 = 5.71 µ
• This is known as calibration factor.

Introduction To Pharmacognosy

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