Pharmacognosy -1

Mr Chandresh Maurya (M.Pharm Pharmacognosy)

Unit-4

Unit-4
Pharmacognosy-I

B.Pharma 4 Semester Notes

UNIT-IV
Pharmacognosy in various systems of medicine:
Role of Pharmacognosy in allopathy and traditional systems of medicine namely, Ayurveda,
Unani, Siddha, Homeopathy and Chinese systems of medicine.

Introduction to secondary metabolites:

Definition, classification, properties and test for identification of Alkaloids, Glycosides,
Flavonoids, Tannins, Volatile oil and Resins

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Mr Chandresh Maurya (M.Pharm Pharmacognosy)

Pharmacognosy in various systems of medicine:

Role of Pharmacognosy in Allopathy:
• Pharmacognosy, the study of natural products from plants, animals, and other
organisms, plays a importants role in the development and advancement of allopathic
medicine.
• Allopathy, also known as conventional or Western medicine, relies heavily on
evidence-based practices and pharmaceuticals.
• The Word “Allos means = Opposite” and “Pathos means= Suffering”
• In this system the drugs/medicine (tablets, Capsules, Injections, Tonics, etc.) are
manufactured using synthetic chemicals or chemical derived from natural products
like plants, animals, minerals, etc.
• Role of Pharmacognosy in Allopathy is that Natural products isolated from plants,
Animals, marine, mineral acts as the major source for modern medicine. Ex: Taxol
from taxus, Digoxin from digitalis, etc.

Advantage of Allopathy
• Modern Technology
• Immediate Response
• Various kinds of dosage forms are available
• Efficient management in emergency conditions.

Disadvantage of allopathy:
• High Cost
• Drug-Drug Interaction
• Long term medicine treatment cause side effect

Traditional systems of medicine namely:

• India is known for its traditional medicinal systems—Ayurveda, Siddha, and Unani.
Medical systems are found mentioned even in the ancient Vedas and other scriptures.
The Ayurvedic concept appeared and developed between 2500 and 500 BC in India.

Types:
• Ayurveda
• Unani
• Siddha
• Homeopathy
• Chinese systems of medicine

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Mr Chandresh Maurya (M.Pharm Pharmacognosy)

Ayurveda System:
• Ayurveda, derived from the Sanskrit words "Ayur" (life) and "Veda" (science or
knowledge), translates to "the science of life." It is one of the world's oldest holistic
healing systems, developed more than 3,000 years ago in India.
• Ayurveda is a way of life that prioritizes harmony and balance in the body, mind, and
spirit in addition to being a medical system.
• The ancient Indian writings known as the Vedas, especially the Atharva Veda, are the
source of Ayurveda.
• The Charaka Samhita, Sushruta Samhita, and Ashtanga Hridaya are the three main
canonical books of Ayurveda.
• These books provide a thorough foundation for comprehending the human body and
psyche by outlining several facets of health, illness, and treatment options.
Fundamental Principles:
The Five Elements (Panchamahabhuta)
According to Ayurveda, the universe and everything in it, including the human body, are
composed of five elements:
1. Prithvi (Earth)
2. Jala (Water)
3. Teja (Fire)
4. Vayu (Air)
5. Akasha (Ether)
These elements combine in various ways to form the three doshas (biological energies) that
govern human physiology.
The Three Doshas
The doshas are fundamental principles that determine the physical and mental characteristics
of an individual, as well as their predisposition to certain health conditions. The three doshas
are:
1. Vata (Air and Ether): Governs movement, including the movement of nerve
impulses, blood flow, and elimination. It is associated with qualities such as dryness,
lightness, coldness, and mobility.
2. Pitta (Fire and Water): Responsible for transformation, including digestion,
metabolism, and body temperature regulation. It is characterized by heat, sharpness,
and intensity.
3. Kapha (Earth and Water): Controls structure and lubrication, providing stability,
strength, and immunity. It is associated with heaviness, steadiness, and coolness.

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Health and Disease

In Ayurveda, health is defined as the balance of the three doshas, the seven tissues (dhatus),
the digestive fire (agni), and the proper elimination of wastes (malas). Disease is seen as a
result of imbalances in these elements, often caused by poor diet, improper lifestyle,
environmental factors, and emotional disturbances.

Methods of Treatment
Nutrition and Diet (Ahara)

In Ayurveda, eating is considered the most important factor in preserving health and warding
off illness. Nutritional advice is tailored according to the dosha of the individual, the season,
and their particular health issue. Foods are classified based on their influence on the doshas,
taste (rasa), potency (virya), and post-digestive effect (vipaka).
Medical Herbal (Dravya Guna)
Herbal remedies created from organic materials such as plants, minerals, and animal products
are frequently used in Ayurvedic treatments. Herbs including ashwagandha, turmeric, tulsi
(holy basil), triphala, and neem are frequently utilized. Certain qualities of these plants are
said to balance the doshas and improve health.

Panchakarma

Panchakarma is a detoxification and rejuvenation therapy involving five primary

procedures:
1. Vamana (Emesis Therapy)
2. Virechana (Purgation Therapy)
3. Basti (Enema Therapy)
4. Nasya (Nasal Administration)
5. Raktamokshana (Bloodletting Therapy)
These procedures are designed to eliminate toxins from the body and restore dosha
balance.
Seasonal Regimens (Ritucharya)

• Seasonal changes can affect dosha balance, and Ayurveda prescribes specific
regimens for different seasons to maintain health and prevent disease.
• This includes dietary adjustments, lifestyle modifications, and herbal supplements
appropriate for each season.
Yoga and Meditation

• Yoga and meditation are integral parts of Ayurveda. They help in maintaining
physical health, mental clarity, and emotional stability.

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• Yoga postures (asanas) promote flexibility, strength, and balance, while meditation
practices (dhyana) enhance mental peace and self-awareness.
Diagnostic Methods
Ayurvedic diagnosis involves a holistic assessment of the patient, including:
1. Nadi Pariksha (Pulse Diagnosis): Evaluating the pulse to understand the balance of
doshas.
2. Jihva Pariksha (Tongue Examination): Assessing the tongue for signs of
imbalance.
3. Drik Pariksha (Eye Examination): Observing the eyes for clues about internal
health.
4. Sparsha Pariksha (Touch Examination): Examining the skin, temperature, and
texture.
5. Shabda Pariksha (Sound Examination): Listening to the voice and breathing
patterns.
6. Akruti Pariksha (General Appearance): Observing the body's shape and overall
appearance.

Unani System:
• The Unani medical system is one of the oldest and is based on the teachings of
Hippocrates, the Father of Medicine, who, in 460 BC, freed medicine from the purview
of superstition and magic to become a recognized science.
• It is a holistic approach to medicine that takes care of the body at every stage (well and
ill).
• The system provides integrated healthcare with a focus on preventive, promotive,
curative, and rehabilitative treatment. While UNANI comes from the term IONIAN,
which indicates that it originated in modern-day Greece, TIBB is a name that suggests
medicine (Unan).
• The Unani system originated in Persian and Arab regions. About a millennium ago,
Arabs brought it to the Indian subcontinent.
• This became its permanent home and the pinnacle of its scientific advancement. This
method has been so successfully assimilated into Indian culture over the ages that the
Indian government now recognizes it as one of the Indian medical systems and includes
it as a fundamental component of our country's healthcare delivery system.
Fundamentals of Unani System of Medicine:
In Unani system of medicine, human body is based on seven natural principles, known
as “Umure Mobile”.These are the very factors responsible for the existence of the human
body and are considered responsible for the maintenance of health.
The loss of any one of these components could lead even to death of the individual.
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These are as follows:
1. ELEMENTS {Arkan Or Anasir)
2. TEMPRAMENT {Mizaj)
3. HUMOURS {Akhlat)
4. ORGANS {Aza)
5. PNEUMA OR VITAL SPIRIT {Arwah)
6. FACULTIES OF POWER (Qii»'
7. FUNCTION {Al-Af’al)

Unani system is based on the Hippocratic theory which postulates that a perfect balance of
"Arkan” (elements), "Akhlat” (humors) and "Mizaj" (temperament) keeps the body and
mind healthy.
The theory presupposes the presence of four humours in human body- "Dam"
(blood) "Balgham" (phlegm), "Safra" (Yellow bile) and Sauda (black bile).Every
individual has an inherent power of self-preservation called the "Quwwat-e-Modabbira"
Unani system of medicine aims at restoring the equilibrium of various elements and faculties
of the human body.

Prevention of Diseases & Promotion of Health:

• In Unani medicine much emphasis is on the prevention of the disease and promotion
of health than to cure.
• It also recognizes the influence of surrounding and ecological conditions on the
state of health of human beings. Baqa e-sehath (preservation of health) has been
defined under Asbabe-Sittah Zaruriah.Asbabe-Sittah Zaruriah (six essential factors
of health) influence each and every individual and all mental and physical diseases
are due to their imbalance.
• For the maintenance of good health these essential factors should be balanced in
terms of quality, quantity and sequence in order to sustain good health.
• Balanced relationship between these factors keeps the humours and temperament on
the right track. The best possible way of health promotion in this holistic system of
medicine is improvement of Tabiyat (Medicatrix nature or immunity).

Asbab-e-sittah zaruriyah:
Asbab-e-sittah zaruriyah are six essential factors necessary for healthy life described by
ancient Unani physicians.
Allama Nafees defined the Asba-e-sittah zaruriyah “these are the factors which accompany a
person for whole life”
Unani scholars classified these factors into six therefore these are called Asbab-e-sittah
zaruriyah (six essential factors for healthy life). It includes the following six factors.
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1. HAWA(Environmental Air)
2. MAKOOL WA MASHROOB(Food and Drinks)
3. HARKAT WA SUKOON BADNI(Physical Movement and Repose)
4. HARKAT WA SUKOON NAFSANI (Psychic Movement and Repose)
5. NAUM WA YAQZA(Sleep and Wakefulness)
EHTABAAS WA ISTAFRAAGH (Retention of Nutritive material and Regular Excretion of
waste material)
• Diagnosis In Unani
In unani system of medicine the most important aspect forthe diagnosis of diseases
are three in number,and they are Nabo (pulse), examination
of boiif (urine) and Barak (stool).

• The surroundings and the ecological conditions are very much responsible for
the state of health of a person. Much emphasis is laid on the causes for
the prevention of health as {asbab sittah zaruriyah) are taken into consideration as
well as on the Mizaj (temperament) of the diseased.

Siddha System:
• Siddha medicine is one of the most ancient medical systems of India. Siddha is the
mother medicine of ancient Tamils/Dravidians of peninsular South India.
• The word Siddha means established truth. The persons who were associated with
establishing such a Siddha school of thought were known as Siddhars.
• They recorded their mystic findings in medicine, yoga, and astrology in Tamil.
• According to the Siddha system, there are five elements that exist in nature: earth,
water, fire, air, and ether, all of which form the original basis of all corporeal things.
• It is believed that there is an intimate connection between the macrocosm of the
external world and the microcosm of the corporeal being.
• The Eight Methods of Examination (Envakai Thervukal) is used to determine
diagnosis, etiology, treatment and prognosis.
• Siddha has safe herbal and herbo mineral treatment for psoriasis, eczema, alopecia,
diabetic ulcer, warts, vitiligo, pemphigus, pompholyx, leprosy, and many more very
common and rare diseases. Lifestyle modifications including diet are important.

Homeopathy System of Medicine:

• The Homeopathy word “Homois means like (similar)” and “Pathos means treatment”
• Homeopathy is an alternative medicine based on the theory of treating 'like with like'.
• The substance capable of causing disorder in health subjects are used as medicines in
diluted form to treat similar pattern of disorder.

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• This system of medicine was introduced by Dr. Samuel Hahnemann in 1755 — 1843.
He was a German physician, chemist and a pharmacist based on the natural law of
healing. i.e like with like.

Principle of Homeopathy:
1. Law of Minimum: The dose needs to be as low as possible in order to excite the
human body and cause noticeable change, which varies from person to person. The
"Arndt-Schulz rule," which states that mild stimuli accelerate vital processes,
moderate stimuli enhance them, and strong stimuli repress them, has long been
recognized in the field of pharmacology.
2. The phenomenon known as "Hormesis" has recently attracted attention and, at the
same time, provided homoeopathic microdosages with legitimacy by demonstrating
that the effects of small doses are opposite those of big ones.
3. Law of Simplex: Simple and single drugs should be prescribed at a time.
4. Law of proving: Drugs are administratered in minimum quantity to prevent unwanted
side effects.
5. Drug proving: To apply drugs for therapeutic purpose their curafive power should be
known.
6. Individualization: Medicines can never be prescribed on the basis of name of disease
without individualizing each case of disease.

Treatment:
• Patients will be asked about their medical history, diet, lifestyle, physical and
emotional state.
• Suitable remedy will be prescribed on the basis of patient's individual symptoms.

Chinese systems of medicine:

• It is also ancient dated back to yellow Emperor's classic of Internal medicine (Huang
Di Nei Jing)-200 BC and 100 AD.
• Based on the idea “all life is subject to natural laws”
• The hypothesis includes two two “yin and yang” theory
• Says that everything in the universe consists of a dark (yin) and light side (yang).
• The five elements (water, metal, earth, fire and wood).
• The differ in diagnosis and treatment

Traditional Chinese medicine system consists of 3 parts.

1. Theory:
a. Yin and Yang Theory

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Mr Chandresh Maurya (M.Pharm Pharmacognosy)
b. Five elements Theory
2. Treatment:
a. Herbalism
b. Acupuncture
c. Moxibustion
d. Cupping
e. Massage Therapy
Prevention:
a. Qi gong
b.
c. Meditation

1. Theory:
a. Yin and Yang Theory:
It is a concept of dualism. Yang predominates during the day and turns into
yin after dark.
In human body when the Yin and Yang elements are well balanced the person
is in good health. A person falls sick when the balance is disturbed.

Lifi

Dav
Odd
Sun

Yin and Yang in Body:

Yin Yang
Lower Body Upper Body
Chest and Abdomen Shoulders and Back
Fluid Gas
Interior Exterior
Internal organs Bowels
Nourish Cleanse
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Mr Chandresh Maurya (M.Pharm Pharmacognosy)
b. Five elements Theory :
The five viral organs (the heart, liver, spleen, lungs, and kidneys) are each
seen as corresponding to one of the five elements of earth, wood, metal, fire
and water.
It is believed a pathological change in any of the vital organs will affect the
health of the other organs.

2. Treatment:
a. Herbalism: The practice of using plants for medicinal purposes. It involves
using various parts of plants, like leaves, roots, flowers, and fruits, to create
remedies for a wide range of health conditions. Herbalism has a long history
across many cultures, and it's still practiced today, often alongside
conventional medicine.

b. Acupuncture: A traditional Chinese medicine (TCM) technique that involves

inserting thin needles at specific points on the body. The goal is to stimulate
the flow of qi (vital energy) and restore balance in the body. Acupuncture is
often used for pain relief, but it may also be used for other conditions like
nausea, anxiety, and allergies.

c. Moxibustion: Another TCM technique that uses the burning of the herb
mugwort near specific acupuncture points on the body. The heat is believed to
stimulate the flow of qi and promote healing. Moxibustion is often used in
conjunction with acupuncture for pain relief and other conditions.

d. Cupping: A traditional therapy that involves placing suction cups on the skin.
The suction can help draw blood to the surface, which is thought to promote
healing, reduce pain, and improve circulation. Cupping therapy is sometimes
used for muscle tension, pain, and respiratory problems.

e. Massage Therapy: The practice of manipulating the soft tissues of the body
(muscles, connective tissues, skin) to improve health and well-being. Massage
therapy can help relieve pain, improve circulation, reduce stress, and promote
relaxation. There are many different types of massage therapy, each with its
own techniques and benefits.

3. Prevention:
a. Qi Gong:
It is the Chinese form of exercise. It regulates the mind and breathing to
promote the flow of energy.
b. Tia chi:
It involves gentle dance like- body movements with mental focus, breathing
and relaxation.

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Introduction to secondary metabolites:
• Definition, classification, properties and test for identification of Alkaloids,
Glycosides, Flavonoids, Tannins, Volatile oil and Resins

Introduction to secondary metabolites:

Primary metabolites:
• Primary metabolites are compounds that are commonly produced by all plants and
that are directly used in plant growth and development.
• They do not possess biological or therapeutic activity.
• They are widely distributed in plants in large quantiles.
• These are directly involved in growth and development of plant. Non expensive to
isolate from plant.
Eg: Carbohydrates, Proteins, Lipids

Secondary metabolites:
• These are biosynthesized from the primary metabolites and alkaloids, glycoside,
tannins, flavonoids, volatile oils and resin.
• They are limited in distribution. Restricted to taxonomic group. Not directly involved
in the growth and development.
• They are not present in all plants but are present in specific part of plant and family.
Eg:
• Alkaloids Tannins
• Volatile Oils : Resine
• Glycosides : Flavonoids

Alkaloids:
• Alkaloids Alkaloids are a class of naturally occurring organic nitrogen-containing
bases.
• They are found primarily in plants and are especially common in certain families of
flowering plants.
• In fact, as many as one-quarter of higher plants are estimated to contain alkaloids, of
which several thousand different types have been identified.
• Well-known alkaloids include morphine, strychnine, quinine, ephedrine, and nicotine.
Properties of Alkaloids
• Alkaloids are basic nitrogenous organic compounds found in plants.
• They are usually secondary metabolites, produced as a defense against herbivores.
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• Alkaloids are usually water soluble and basic (pH > 7), which makes them relatively
polar.
• The basic structure of an alkaloid is a nitrogen-containing cyclic system with one or
more rings.
• They almost uniformly evoke a bitter taste.

Identification Tests for Alkaloids:

There are several chemical tests for the identification of alkaloids.
1. DragendorfPs Test:

• Reagent: Dragendorff s reagent (potassium bismuth iodide solution).

• Positive Result: Orange or red precipitate.
2. Mayer's Test:

• Reagent: Mayer's reagent (potassium mercuric iodide solution).

• Positive Result: Cream or white precipitate.
3. llager's Test:

• Reagent: Hager's reagent (saturated solution of picric acid).

• Positive Result: Yellow precipitate.

4. Wagner's Test:
• Reagent: Wagner's reagent (iodine in potassium iodide).
• Positive Result: Reddish-brown precipitate.

Classification of Alkaloids:
They are classified into 3 main classes:
1. True Alkaloids
2. Protoalkaloids
3. Pseudoalkaloids

True alkaloids:
• They derived from amino acids.
• They having nitrogen in heterocyclic ring.
• These alkaloids are highly reactive substances with biological activity even in low
doses.
• True alkaloids may occur in plants
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a) in the free state
b) as salts
c) as N-oxides.
• The primary precursors of true alkaloids are such amino acids as L- ornithine, L-
lysine, L-phenylalanine/L-tyrosine, L-tryptophan and L- histidine.
• Examples of true alkaloids include such biologically active alkaloids as cocaine,
quinine, dopamine and morphine, nicotine, atropine, tubocurarine, strychnine.

Proto alkaloids :
• They derived from amino acids. But they do not have nitrogen in heterocyclic ring.
• Such kinds of alkaloid include compounds derived from L-tyrosine and L-tryptophan.
• Protoalkaloids are those with a closed ring, being perfect but structurally simple
alkaloids.
• They form a minority of all alkaloids.
• Eg: tyramine, histamine, ephedrine, yohimbine ,mescaline, choline.
Pseudo alkaloids :
• Not derived from amino acids.
• They have nitrogen in heterocyclic ring.
• Pseudoalkaloids are compounds, the basic carbon skeletons of which are not derived
from amino acids.
• In reality, pseudoalkaloids are connected with amino acid pathways. They are derived
from the precursors of amino acids.
• They can also result from the amination and trans-amination reactions of the different
pathways connected with precursors of amino acids.
• These alkaloids can also be derived from non-amino acid precursors.
• Eg: coniine, capsaicin, ephedrine, solanidine, caffeine and theobromine.

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Glycosides:
• Glycosides are define as organic compound from plants and animal source, which
upon hydrolysis gives one or more sugar moieties along with a non-sugar moiety.
• Sugar portion is called glycon
• Non-sugar portion is called aglycon or genin.
• Sugar moiety can be glucose, xylose, galactose, mannose, rhamnose, etc.
• While non-sugar moiety or aglycon moiety can be alcohol, phenol, anthraquinone,
sterol, flavanol, etc.
• Linkage between sugar and non-sugar portion is usually called as glycosidic linkage.
Properties of Glycosides
• Glycosides are usually solid and amorphous powder.
• They are mostly water-soluble but insoluble in organic solvents.
• Most glycosides are colorless, but some are colored.
• They are mostly bitter, except for certain types like Glycyrrhizin, Stevioside, Populin.
• They are odourless, except for Saponin glycoside.
• Glycosides are stable under neutral or basic conditions.

Identification Tests for Glycosides

There are several tests that can be used to identify glycosides
1. Legal's Test: This test involves observing the reaction mixture for any color change.
2. Antimony Trichloride Test: This test involves the formation of a pink color upon
heating, indicating the presence of steroids and triterpinoids.
3. Tetranitro Methane Test: The formation of a yellow color indicates the presence of
sterol and triterpenoid.
4. Libermann Burchard Test: The appearance of a violet ring followed by a blue color
indicates the presence of a sterol group in the drug.
5. Salkowaski Test: The appearance of a yellow-colored ring that turns red indicates the
presence of a sterol group in the drug.

Classification of Glycosides:
• The glycosides can be classified by the glycone, by the type of glycosidal linkage, and
by the aglycone.
On the Basis of Glycone
If the glycone group of a glycoside is glucose, then the molecule is a glucoside; if it is
fructose, then the molecule is a fructoside; if it is glucuronic acid, then the molecule is a
glucuronide, etc.
On the Basis of Glycosidic Linkage

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1. O-glycosides: Sugar molecule is combined with phenol or —OH group of aglycon, for
example, Amygd-aline, Indesine, Arbutin, Salicin, cardiac glycosides, anthraxquinone
glycosides like sennosides etc
2. N-glycosides: Sugar molecule is combined with N of the —NH (amino group) of
aglycon, for example, nucleosides
3. S-glycosides: Sugar molecule is combined with the S or SH (thiol group) of aglycon,
for example, Sinigrin.
4. C-glycosides: Sugar molecule is directly attached with C—atom of aglycon, for
example, Anthraquinone glycosides like Aloin, Barbaloin, Cascaroside and Flavan
glycosides, etc.
On the Basis of Aglycone
The various classes according to aglycone moiety are given below:
S.No. Class Examples
1. Anthraquinone glycosides Senna, Aloe, Rhubarb, etc.
2. Sterol or Cardiac glycosides Digitalis, Thevetia, Squill, etc.
3. Saponin glycosides Dioscorea, Liquorice, Ginseng, etc.
4. Cyanogenetic and Cyanophoric Bitter almond, Wild cherry bark,
glycosides etc.
5. Thiocynate and Isothiocynate Black mustard
glycosides
6. Flavone glycosides Ginkgo
7. Aldehyde glycosides Vanilla
8. Phenol glycosides Bearberry
9. Steroidal glycosides Solanum
10. Bitter and Miscellaneous glycosides Gentian, Picrrohiza, Chirata, etc

Flavonoids:
• Flavonoids are a type of phytochemical or plant chemical that are widely distributed
in the plant kingdom.
• They create the vibrant colors of many fruits, vegetables, and flowers, and have been
found to have a variety of health benefits.

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Properties of Flavonoids:

• Soluble in Water and alcohol.

• Insoluble in organic solvents.
• They are optically active.
• Crystalline solid with sharp melting point.
• They lowers the cholesterol level.

Test for Identification

1. Shinoda test: The extract is treated with magnesium turnings and hydrochloric acid. The
development of a pink or red color indicates the presence of flavonoids.
2. Ferric Chloride Test
• Procedure:

1. Add 1-2 mL of the plant extract to a test tube.

2. Add a few drops of 1% ferric chloride (FeCl3) solution.
3. Observe the color change.

• Positive Result: Formation of a dark green, black, or blue-green coloration suggests

the presence of phenolic hydroxyl groups, characteristic of flavonoids.
3. Lead Acetate Test
• Procedure:
1. Add 1-2 mL of the plant extract to a test tube.
2. Add a few drops of 10% lead acetate solution.
3. Observe the formation of a precipitate.
• Positive Result: Formation of a yellow precipitate indicates the presence of
flavonoids.
4. Alkaline Reagent Test
• Procedure:
1. Add 1-2 mL of the plant extract to a test tube.
2. Add a few drops of sodium hydroxide (NaOH) solution.
3. Observe the color change.
4. Acidify the solution with dilute hydrochloric acid (HCI).

• Positive Result: An intense yellow color that fades upon acidification indicates the
presence of flavonoids.
5. Zinc Hydrochloride Reduction Test
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• Procedure:
1. Add 1-2 mL of the plant extract to a test tube.
2. Add a few pieces of zinc dust.
3. Add 1-2 drops of concentrated hydrochloric acid (HCI).
4. Heat the mixture gently.

5. Observe the color change.

• Positive Result: Development of a red color indicates the presence of flavonoids.
6. Sulfuric Acid Test

• Procedure:
1. Add 1-2 mL of the plant extract to a test tube.
2. Add a few drops of concentrated sulfuric acid (H2SO4).
3. Observe the color change.
• Positive Result: Development of a yellow or orange color indicates the presence of
flavonoids.

Classification of Flavonoids:
Flavonoids can be classified in†o several groups based on †heir chemical
s†ruc†ure. Here are †he main classes of flavonoids:

1- An†hocyanidins: These are pigments found in red/blue frui†s and

flowers. Examples include cyanidin, delphinidin, and malvidin.
2. Flavonols: These are a †ype of flavonoid usually found in onions, leeks,
and broccoli. Examples include querce†in and kaempferol.
3. Flavanones: Found mainly in ci†rus frui†s. Examples include hesperidin
and naringenin.
4. FIavan-3-oIs: These are †he mos† common †ype of flavonoid, including
ca†echins which are found in green †ea.
s. Flavanonols: A †ype of flavonoid †ha† includes compounds like †axifoIin.
6. Flavones: These are found in parsley and celery. Examples include
apigenin and Iu†eoIin.
7- Isoflavones: These are mos† commonly associated wi†h soy and soy
products. Examples include genis†ein and daidzein.

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Tannins:
• Tannins are a class of astringent, polyphenolic biomolecules that bind to and
precipitate proteins and various other organic compounds including amino acids and
alkaloids.
• They are widely distributed in many species of plants, where they play a role in
protection from predation (acting as pesticides) and might help in regulating plant
growth.
Properties of Tannins:
1. Tannins are colloidal solutions with water.

2. Non crystalline substance.

3. Soluble in water (exception of some high molecular weight structures), alcohol, dilute
alkali, and glyc-erin.
4. Sparingly soluble in ethyl acetate.
5. Insoluble in organic solvents, except acetone.

Identification test of Tannins:

Several tests can be used to identify the presence of tannins in a sample:
1. Ferric Chloride Test

• Procedure:
1. Add 2-3 mL of the extract to a test tube.
2. Add a few drops of 1% ferric chloride (FeCl3) solution.

3. Observe the color change.

• Positive Result: A blue-black, green, or dark blue color indicates the presence of
hydrolyzable tannins. A brownish-green or black color indicates the presence of
condensed tannins.

2. Gelatin Test
• Procedure:
1. Add 2-3 mL of the extract to a test tube.

2. Add a few drops of 1% gelatin solution containing 10% sodium chloride

(NaCl).
3. Observe the formation of a precipitate.
• Positive Result: The formation of a white or cloudy precipitate indicates the presence
of tannins.

3. Lead Acetate Test

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Mr Chandresh Maurya (M.Pharm Pharmacognosy)
• Procedure:
1. Add 2-3 mL of the extract to a test tube.
2. Add a few drops of 10% lead acetate solution.
3. Observe the formation of a precipitate.
• Positive Result: The formation of a white or yellowish precipitate indicates the
presence of tannins.
4. Bromine Water Test
• Procedure:
1. Add 2-3 mL of the extract to a test tube.

2. Add a few drops of bromine water.

3. Observe the color change.

• Positive Result: Decolorization or a yellow precipitate indicates the presence of

tannins.
5. Goldbeater's Skin Test
• Procedure:
1. Soak a small piece of goldbeater's skin (ox skin) in 2% hydrochloric acid
(HCI) for about 5 minutes, then rinse with distilled water.
2. Soak the treated skin in the plant extract for about 5 minutes.
3. Wash the skin with distilled water.
4. Immerse the skin in a 1% ferric chloride solution for 5 minutes.
5. Observe the color change of the skin.
• Positive Result: The skin turning brown or black indicates the presence of tannins.

6. Vanillin-Hydrochloric Acid Test

• Procedure:
1. Add 1 mL of the extract to a test tube.
2. Add 1 mL of vanillin-hydrochloric acid reagent (prepared by dissolving 1 g of
vanillin in 100 mL of 8% HCl in ethanol).

3. Observe the color change.

• Positive Result: The development of a pink or red color indicates the presence of
condensed tannins.
7. Stiasny's Test

• Procedure:
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 Pharmacognosy -1 Unit-4
Mr Chandresh Maurya (M.Pharm Pharmacognosy)
1. Add 10 mL of the extract to a test tube.
2. Add 5 mL of Stiasny's reagent (a mixture of formaldehyde and concentrated
HCl).
3. Heat the mixture in a water bath at 70-80°C for 30 minutes.
4. Observe the formation of a precipitate.
• Positive Result: The formation of a red-brown precipitate indicates the presence of
condensed tannins.
Classification of Tannins:
(i) Hydrolysable tannins
(ii) Condensed tannins
(iii) Pseudo tannins.
Hydrolysable tannins:
• These tannins are hydrolyzed by acids, or enzyme and produce gallic acid and ellagic
acid. Chemically, these are esters of phenolic acid like gallic acid and ellagic acid.
• The tannins derived from gallic acid are known as gallitannins and from that of ellagic
acid are known as gallitannins.
• The gallic acid is found in rhubarb, clove and ellagic acid is found in eucalyptus leave
and myrobalans and pomegranate bark. These tannins treated with ferric chloride to
produced blue or black colour.
Condensed tannins:
• These tannins are resistant to hydrolysis and they derived from the flavonols,
catechins and flavan-3, 4-diols. On treatment with acids or enzymes they are
decomposed into phlobaphenes.
• On dry distillation condensed tannin produce catechol.
• These tannins are called as catechol tannins.
• These tannins are found in cinchona bark, male fern, areca seeds, tea leaves and wild
cherry bark, bahera fruits, Amla, etc. they produce green colour with ferric chlorides.
Pseudo tannins:
• They are phenolic compounds of lower molecular weight and do not show the
goldbeater's test. They are found in catechu and nux-vomica, etc.

Volatile Oil:
• Volatile oils, also known as essential oils, are mixtures of hydrocarbon terpenes,
sesquiterpenes, and polyterpenes and their oxygenated derivatives obtained from
various parts of plants.
• They are responsible for the essence or odor of the plant. When fresh, volatile oils are
colorless liquids, but a few are crystalline or amorphous solids.

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• On long standing, they become darker in color, especially when exposed to air and
direct sunlight.
Properties
• Volatility: Volatile oils evaporate on exposure to air at ordinary temperature.
• Solubility: They are slightly soluble in water but are readily soluble in ether, alcohol,
and most organic solvents.
• Color: When fresh, volatile oils are colorless liquids. A few are crystalline or
amorphous solid.
• Odor: They emit strong, often pleasant odors.
Identification tests for Volatiles Oils:
Natural drugs containing volatile oils can be tested by following chemical tests:
1. Thin section of drug on treatment with alcoholic solution of Sudan III develops red
colour in the presence of volatile oils.
2. Thin section of drug is treated with tincture of alkana, which produces red colour that
indicates the presence of volatile oils in natural drugs.

Classification of Volatile Oils:

0
Groups Drugs
Hydrocarbons Turpentine oil
Alcohols Peppermint oil, Pudina, Sandalwood oil, etc.
Aldehydes Cymbopogon sp., Lemongrass oil, Cinnamon,
Cassia, and Saffron
Ketones Camphor, Caraway and Dill, Jatamansi, Fennel, etc.
Phenols Clove, Ajowan, Tulsi, etc.
Phenolic ethers Nutmeg, Calamus, etc.
Oxides Eucalyptus, Cardamom, and Chenopodium oil
Esters Valerian, Rosemary oil, Garlic, Gaultheria oil, etc.

Resines:
• Resins are the class of secondary metabolites which are sticky, flammable, organic
compounds insoluble in water and are exuded by some plants and trees.
• Plans secrete resins for their protective benefits in response to injury.
• It protects the plants from insects and pathogens.
Properties:
• They are insoluble in water and usually insoluble in petroleum ether.
• Chemically inert compounds known as resenes.
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Classification:
On the basis of occurance with other secondary metabolites (Resin combination)
i) Oleo resin : Naturally occuring mixture of resin & volatile oil ex: Ginger, capsicum,
copaiba
ii) Gum Resin: Resin associated with gum example: colophony, cannabis
iii) Oleo Gum Resin: Mixture of volatile oil, Gum & resin Ex: Guggul, Asafoetida,
Myrrh

iv) Balsam Resin: Resinous mixture of benzoic acid/ cinnamic acid or esters of tehse
acids in free or combined form Ex: Benzoin, Tolu balsam, peru balsam
v) Glycoresins: occur in combination with sugar by Glycoside linkage Ex: Jalap,
Podophyllum, Ipomoea
Identification Test for Resin:
1. Benzoin: Benzoin + Ether shake Extract +H SO sumatra benzoin deep brown
2 4
color & siam benzoin (deep purple color)
2. Colophony : Drug + acetic anhydride + 1 drop of Conc. H SO
2 4

Purple color that rapidly changes to violet color

3. Myrrh: Triturate with solvent ether Filter—› Evaporate thin film —› violet color on
contact with Br vapor
2

Triturate with water Yellow emulsion

4. Podophyllum: Drug+ alcohol Macerate Filter Filtrate + strong copper acetate
solution Brown ppt
5. Tolu balsam: Acidic to litmus
Drug + FeCl3 Green color (Resinotannol)

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