ROLE OF PHARMACOGNOSY IN ALLOPATHY

Allopathy medicine is a part of the Western medical system. In this system, drugs are manufactured using synthetic chemicals or chemicals derived from natural products like plants, animals, or mineral sources. Various drugs like tablets, capsules, injections, tonics, etc., are used. It also utilizes modern equipment for diagnosis, analysis, and surgery.

Doctors treat disease based on symptoms, not primarily on causes. This system is also known as evidence-based or modern medicine. A main drawback is that most drugs have side effects.

The role of Pharmacognosy in Allopathy is significant as Natural products isolated from plants, animals, marine sources, or minerals act as a major source for Modern Medicine. Examples include: Taxol from Taxus, Digoxin from Digitalis, Morphine and Codeine from Opium, and Vincristine from Vinca.

Pharmacognosy plays a diverse role in the discovery, characterization, production, and standardization of these drugs. It is used by pharmaceutical companies to screen, characterize, and produce new drugs for the treatment of multiple human diseases. Thus, natural compounds provide excellent models to discover novel drugs. Digitalis, a most important medicinal plant, is directly used in Allopathy medicine for its cardioprotective action.

ROLE OF PHARMACOGNOSY IN TRADITIONAL SYSTEM OF MEDICINE

Role of Pharmacognosy in Ayurveda

• Ayurveda is an Upaveda of Atharvaveda.
• It is the dominant herbal tradition in India and the oldest system of healing in the world.

Principle of Ayurveda

The principle of Ayurveda is based on the concept of five basic elements and Tridoshas. According to Ayurveda, the whole universe is made up of five basic elements (Panchamahabuthas):

• Akasha (Ether)
• Vayu (Air)
• Agni (Fire)
• Jala (Water)
• Prithvi (Earth)

Vata, Pitta, and Kapha together are called Tridosha (three pillars of life).

Tridosha and Panchamahabuthas

• Vata: (Air + Space)
• Pitta: (Fire + Water)
• Kapha: (Water + Earth)

These three doshas influence the Saptadhatu (Seven Forms in Human Body):

• Rasa (Lymph / Plasma)
• Rakta (Blood)
• Mamsa (Flesh / Muscle)
• Meda (Adipose tissue / Fat)
• Asthi (Bones)
• Majja (Nervine tissue / Marrow)
• Shukra (Reproductive tissue / Sperm/Ovum)

When tridosha, saptadhatu, and mala are in balance, it is called a healthy condition; imbalance causes a pathological condition.

It is hypothesized that the five characters of medicinal herbs, namely Rasa, Guna, Virya, Vipak, and Prabhava, can be applied to treat various pathological conditions. Health or sickness depends on the presence or absence of a balanced state of the total body matrix.

Properties, Location, and Manifestations of Elements

• Ether: Non-resistance; located in body cavities (mouth, thorax, abdomen, lung cavity, digestive tract).
• Air: Related to movements, vibrations, oscillations; manifests muscle movement, heart pulsation, lung expansion/contraction, digestive/nervous system functioning.
• Fire: Concerned with radiation; manifests digestion, metabolism, temperature, vision, intelligence.
• Water: Related to force and cohesion; located in cytoplasm, blood, salivary glands, gastric juice.
• Earth: Concerned with resistance and solidarity; manifests skin, nails, hairs, and bones.

These elements manifest in the functioning of our senses.

TRIDOSHAS - Basic Forces and Pillars of Life

• Vata (Air principle): elements Ether and Air.
• Pitta (Fire principle): elements Fire and Water.
• Kapha (Water principle): elements Earth and Water.

According to Ayurveda, sickness is due to the imbalance of any one or more of the three doshas. E.g., aggravation of Pitta leads to indigestion, skin diseases, and liver problems.

Factors Responsible for Imbalance of Doshas

• Physical, mental, spiritual, and environmental factors may contribute.

Diagnosis in Ayurveda

Diagnosis is carried out to find out which dosha is aggravated. For this purpose, various indicators are examined:

• Nadi (Pulse)
• Jivha (Tongue)
• Akrit (Skin)
• Sabda (Voice)
• Mala (Stool)
• Mutra (Urine)
• Netra (Eye)
• Sparsha (Physical Features)

Treatment in Ayurveda

The importance of treatment is to restore the balance and harmony of doshas with proper diet and drugs.

Selection of Drugs - Based upon:

1. Rasa (Taste)
2. Virya (Potency)
3. Vipaka (Taste after digestion)

RASA (Taste)

Rasa indicates the composition, properties, and probable action of the drugs. Each taste has one or more mahabuthas (elements) and its own influence on doshas. There are six tastes:

VIRYA (Potency)

On the basis of Virya, drugs are classified into hot and cold drugs:

• Hot (Ushna) drugs: Aggravates Pitta and pacifies Vata and Kapha (e.g., garlic, drumstick).
• Cold (Sita) drugs: Aggravates Kapha and Vata and pacifies Pitta (e.g., Jeera, amla).

VIPAKA (Taste after Digestion)

Food and medicine undergo various changes during digestion (metabolism). The taste after digestion is known as Vipaka. The three tastes described under Vipaka are sweet, sour, and pungent:

• Sweet: Aggravates Kapha and alleviates Pitta and Vata.
• Sour: Aggravates Pitta and alleviates Kapha and Vata.
• Pungent: Aggravates Vata and alleviates Kapha.

Role of Pharmacognosy in Unani

• Father of Unani medicine: Hippocrates.
• Introduced in India by the Arabs and Persians.
• Today, India is a leading country in Unani medicine practice.
• Also known as Tibb-e-Unani, Islamic, Oriental, and Arab medicine.

Origin & Development of Unani System

• Hakim Ajmal Khan, a Unani physician and freedom fighter, established an Ayurvedic and Unani Tibbia College and Hindustani Dawakhana.

Principles & Concepts of Unani

Based on two theories:

1. The Hippocratic theory of four humours: blood, phlegm, yellow bile, and black bile.
2. The Pythagorian theory of four proximate qualities: hot, cold, moist, and dry (represented as earth, water, fire, and air).

The humours are also assigned temperaments:

Humour	Temperament
Blood	Hot & Wet
Phlegm	Cold & Wet
Yellow Bile	Hot & Dry
Black Bile	Cold & Dry

Phlegm: Thick, sticky, stringy mucus secreted by the mucous membrane of the respiratory tract.

Yellow bile: A yellow or greenish, viscid fluid, usually alkaline in reaction, secreted by the liver; aids in digestion.

Black bile: A humor once believed to be secreted by the kidneys or spleen and to cause sadness.

The human body is considered to be made up of the following seven components in an interconnected flow:

Arkan (Elements) → Mizaj (Temperament) → Akhlat (Humors) → Aaza (Organs) → Arwah (Spirits) → Quwa (Faculties) → Afaal (Functions)

Elements (Arkan)

The human body contains four elements (earth, air, water, fire). Each has its own temperament:

• Air: Hot and Moist
• Earth: Cold and Dry
• Fire: Hot and Dry
• Water: Cold and Moist

Temperament (Mizaj)

The individual's temperament is believed to be the result of the interaction of these four elements.

Humors (Akhlat)

Humours are moist and fluid parts of the body produced after transformation and metabolism of aliments; they function in nutrition, growth, repair, and energy production.

Organs (Aaza)

These are the various organs of the human body. The health or disease of each individual organ affects the state of health of the whole body.

Spirits (Arwah)

Ruh (Spirit) is a gaseous substance, obtained from inspired air, which aids in all metabolic activities and is the source of vitality for all organs.

Faculties (Quwa)

These are of three kinds:

• Natural power (Quwa Tabiyah): Power of metabolism and reproduction.
• Psychic power: Refers to nervous and psychic power, located in the brain, responsible for perceptive and motive power.
• Vital power (Quwa Haywaniyah): Responsible for maintaining life and enabling organs to accept the effect of psychic power.

Afaal (Functions)

This component refers to the movements and functions of all the organs of the body. In a healthy body, organs are in proper shape and perform their respective functions.

Diagnosis in Unani

Dependent on observation and physical examination, investigating disease causes. Physicians mainly rely on pulse reading and examination of urine and stool.

Physical Examination:

Carried out by diagnosing urinogenital disorders, pathogenesis of blood and other humors, metabolic disorders, and liver diseases. The following observations of urine are made:

• Colour
• Consistency
• Odour
• Foam or froth
• Precipitates

In this system, disease is treated as follows:

Treatment Type	Description
Hajbil Tadbeer (Regimental therapy)	Includes venesection, diaphoresis, diuresis, Turkish bath, massage, cauterization, purging, emesis, and exercise.
Hajbil Ghiza (Diettotherapy)	Deals with treating ailments by administering specific diets or regulating the quantity and quality of food.
Hajbil Dava (Pharmacotherapy)	Deals with the use of naturally occurring drugs, mostly herbal drugs.

Siddha System of Medicine

• It is believed that Lord Shiva unfolded medical knowledge to his wife Parvati, which was then passed to the Siddhars.
• System of pre-Vedic period identified with Dravidian culture, largely therapeutic in nature.
• Also based on three humors (Vata, Pitta, Kapha) and believes everything in the universe is made up of 5 basic elements (earth, water, sky, fire, and air).
• Imbalanced ratio of panchamahabhutas may cause disease.

Predominance of Triguna According to Time in a Day

Time	Guna Predominance
6:00 am to 10:00 am	Vata
10:00 am to 2:00 pm	Pitta
2:00 pm to 6:00 pm	Kapha

Vata Guna

• Characteristics: Stout, black, cold, & inactive personality.
• Increased Vata develops: flatulence, acidity, dysentery, obesity, etc.
• Individuals show: arrogant behavior, partial paralysis, heart attack, neck & chest pain, etc.

Pitta Guna

• Characteristics: Lean, wheatish complexion, hot personality.
• Increased Pitta results in: early greying of hairs, reddish eyes, & more sexual desire.
• Individuals suffer from: anemia, burning chest, mental derangement, etc.

Kapha Guna

• Characteristics: Well-built, good complexion, good-behaved personality.
• More affinity towards sweet food & sex.
• Increased Kapha develops diseases like: jaundice, heart attack, fever, anemia, etc.

Diagnosis in Siddha System

Physicians generally identify causative factors through examination of:

• Nadi (Pulse): Propagation to left side denotes loss of self-control, while propagation to right side shows sign of death.
• Dhwani (Speech/Voice): High sound shows Pitta, low sound denotes low B.P.
• Twaka (Tongue): Boils show imbalance of Vata, bitterness denotes Pitta, white slimy tongue shows low B.P.
• Deiham (Body)
• Malam (Feaces and the status of digestive system): Darker color indicates Vata. Greenish/reddish color indicates Pitta. Whitish color shows Kapha.
• Mutram (Urine): Darker color indicates Vata. Greenish/reddish color indicates Pitta. Whitish color shows Kapha.
• Vizhi (Eyes color): Darker color indicates Vata. Greenish/reddish color indicates Pitta. Whitish color shows Kapha.

Treatment in Siddha System

Treatment takes into account environment, age, sex, race, habits, mental status, habitat, diet, appetite, physical condition, physiological constitution, etc. Vaidya (Physician) has knowledge of herbs & their effectiveness in specific diseases.

Types of Formulations in Siddha System:

Groups	Example
Kashayam	For infants, Jaundice, piles
Churnam	Panchammruta, Kadukai, Ashwagandha
Lehyam	Amla lehya, Ginger lehya, Coconut lehya
Tailam	Bhringamla, Amlahat, Nutmeg, Neem etc.
Bhasmam	Tortoise shell, Egg shell, Snake, Shrunga Bhasma
Chenduram	Rasa chendrum, Chendurams of Copper
Mezhugu	Kasturi wax, Saffron wax, Turmeric wax
Ghrtam	Adhatoda Ghrta, Brahmi Ghrta
Tablets	Kasturi tablet, Saffron tablet

Role of Pharmacognosy in Homeopathy

Etymology: The word "Homeopathy" is derived from two Greek words: Homois (meaning similar) and pathos (meaning suffering).

History of Homeopathy

• The concept of "Like cures like" was first made by Hippocrates about 400 B.C.
• During the 15th to 16th centuries, Dr. Theophastus Von Bombast rejected the principle of opposite acting remedies and stated that same must be cured by same.
• In the 17th century, Dr. George Stahl gave the first precise enunciation of the fundamental homeopathic principle: "I am convinced that disease will disease yield to and be cured by remedies that produce similar affections."
• 1835: First homeopathy medical college was opened in Allentown, Pennsylvania.

Discovery of Modern System of Homeopathy

• Dr. Samuel Hahnemann, Founder of modern Homeopathic treatment, born on April 10, 1755, in Meissen, Saxony (eastern Germany).
• Obtained Doctor of Medicine degree in 1779.
• Stated that there exists a law in medicine which he called the "Law of Similar" and introduced a new principle called similia similibus curantur meaning "like disease are cured by like medicine - like be treated by likes."
• He coined the name Homeopathy, which first appeared in print in 1807.
• The "Discovery of Like treats like" occurred in 1790 while Dr. Hahnemann was translating a book by Dr. William Cullen, "A treatise on Materia Medica," which discussed Cinchona or Peruvian bark for malaria treatment.

Homeopathy simply means treating diseases with remedies, prescribed in minute doses, which are capable of producing symptoms similar to the disease when taken by healthy people.

Fundamental Principles of Homoeopathy

S.NO.	PRINCIPAL	DESCRIPTION
1.	Concept of Individualization	No two individuals are alike, and the disease affecting them cannot be similar. Although individuals may possess common symptoms, the individual response to the same disease would be different; thus, medicines used to cure the same disease in different individuals are different.
2.	Principle of Similar / Law of Similar	Treatment of a disease by a medicine which produces similar symptoms in a healthy individual.
3.	Principle of Simplex	States the use of only a single, simple medicine at one time.
4.	Principle of Minimum Dose	States that the lower the dose of the medication, the greater is its effectiveness. Substances are diluted in a step-wise fashion and shaken vigorously after each dilution (known as Potentisation).
5.	Law of Proving	The method used for determining which remedies were suitable for specific diseases was called proving.
6.	Law of Dynamization and Dilution	Dr. Hahnemann recognized the use of substances that cause symptoms similar to an existing disease. Liquids are diluted with alcohol (ethanol), water, or alcohol/water mixtures, whereas insoluble powders are diluted with lactose (milk sugar).
7.	Law of Vital Force	States that "Life" depends on an important and undetectable "Vital Force" which runs through the body, known as Vitalism, which if disturbed will lead to illness or disease. Homeopathy medicine restores the vital energy balance and stimulates the body's own healing response.

Diagnosis in Homeopathy

Homeopathy usually involves collecting an extremely detailed case history. Patients are asked to describe their medical history and current symptoms.

Treatment in Homeopathy

The treatment is based on the concept of proving and prover:

• Prover: The healthy person.
• Proving: The symptoms (physical, mental, emotional changes) that are caused by the various potencies of medicines in the prover.

For treatment, the symptoms of the drug are compared with the symptoms of the patient. In other words, the selection of the drug depends upon the symptoms of the drug and the patient's condition.

Chinese System of Medicine

• Ancient system, dated back to Yellow Emperor's Classic of Internal Medicine (Huang Di Nei Jing) - 200 BC & 100 AD.
• Based on the idea "all life is subject to natural laws."
• The hypothesis includes two theories: "Yin and Yang" theory and "Five Elements" theory.
• They differ in diagnosis and treatment.

Principles and Theory

Yin-Yang and Qi

• Traditional medicine revolves around the principles of Yin and Yang, which are the opposites found in everything, such as day (Yang) or night (Yin).
• Practitioners believe that every person has a life force known as "Qi."
• The purpose of medicine is to establish a balance of the body's Qi.

Five Elements Theory

• The five vital 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.

Doctrine of Yin and Yang

Yang (Light) Characteristics

• Excess (shi)
• Heat
• Day
• Light
• Warm
• Positive
• Active
• Male
• Hollow Organs: Gall Bladder, Small Intestine, Stomach, Large Intestine, Urinary Bladder

Yin (Dark) Characteristics

• Deficiency (xu)
• Cold
• Night
• Dark
• Cold
• Negative
• Passive
• Female
• Solid Organs: Liver, Heart, Spleen, Lungs, Kidney

"Yin" and "Yáng" originally referred to topographical inclines: "Yin" was the north face of a mountain, and "Yáng" was the south face of a mountain. Yin and Yang are applied to medicine in numerous ways; for example, the upper part of the body is Yang, while the lower body is Yin. When a person is healthy, these Yin and Yang aspects of the body are in harmony (synchronization). E.g., shivering occurs due to excess of Yin, while excess of Yang causes a fever.

Treatments in Chinese System

• Herbalism: Chinese herbal medicine has been used for over 4,000 years, consisting mainly of natural medicinal materials such as plants, animal parts, and minerals.
• Acupuncture: Involves the stimulation of anatomical points on the body with thin needles.
• Moxibustion: A technique involving the burning of mugwort (a small, spongy herb) to facilitate healing.
• Cupping Therapy: Cups are placed on the skin to create suction. Cups can be made of glass, bamboo, or earthenware.
• Massage Therapy (Tui Na): Uses wave-like motions to loosen joints and nourish muscles.

The treatment is done with polyherbs. Examples include Ephedra sinica, Rheum palmatum, Carthamus tinctorius, Clerodendron trichotomum, Panax ginseng etc.

INTRODUCTION TO SECONDARY METABOLITE

Alkaloids

• Alkaloids are colorless, crystalline, nonvolatile, solid, and bitter in taste (exceptions: Betanidine (Red), Sanguinarine (Copper Red), Berberine, Tylophorine (Yellow)).
• Generally optically active, with levo isomers being more active.
• Optically inactive alkaloids include Papaverine, Atropine.
• Liquid alkaloids include Sparteine, Conine, and Nicotine.

Classification of Alkaloids

1. Biosynthetic Classification
2. Pharmacological Classification
3. Taxonomic Classification
4. Chemical Classification

Biosynthetic Classification

Given to the precursor from which alkaloids are produced in plants biosynthetically. Alkaloids derived from the same precursor can be grouped together, regardless of taxonomic distribution or pharmacological activity.

• E.g., Piperidine alkaloids derived from Lysine.
• Pyrrolidine alkaloids derived from Ornithine.
• Indole alkaloids derived from Tryptophan.

Pharmacological Classification

Classification depends upon pharmacological action (e.g., CNS stimulant or depressant, anti-malarial).

• In Cinchona, Quinine is an anti-malarial, whereas Quinidine is a cardiac depressant.
• In Opium, Morphine is a narcotic analgesic, whereas Codeine is an antitussive.

Taxonomic Classification

Classification deals with the 'Taxon' like genus, subgenus, species, and subspecies. A large number of alkaloids are classified based on their families (e.g., Rubiaceous alkaloids and Solanaceous alkaloids).

Chemical Classification

Test for Identification of Alkaloids

Common Tests for Alkaloids

Specific Identification Tests

Glycosides

• Aglycone: Responsible for chemical and therapeutic property.
• Glycone: Determines water and lipid solubility (potency); facilitates absorption of glycoside and helps in transportation of aglycon portion at the site of action.

Hydrolysis of Glycosides: Glycosides — (Enzymatic or Acid Hydrolysis) —> Glycone (sugar/ose) + Aglycone (non-sugar/genin)

Properties of Glycosides

• Colourless, but some are colored (e.g., flavonoids are yellow and anthracene glycosides are red).
• Crystalline or amorphous solid compounds.
• Optically active; normally levo form is more active.
• Soluble in water and alcohol, but insoluble in chloroform and ether.
• Can be hydrolyzed by mineral acid, water, and enzymes.

Classification of Glycosides

1. On the Basis of Pharmacological Action

   TYPE	EXAMPLE
   LAXATIVE AND PURGATIVE	Aloe, Senna, Cascara
   CARDIAC GLYCOSIDE	Digitalis, Strophanthus, Thevetia, Squill
   IMMUNOMODULATOR	Ginseng, Picrorhiza
   EXPECTORANT	Liquorice, Wild cherry bark
   BITTER GLYCOSIDE AND EMETIC	Gentian, Picrorhiza, Chirata, Quassia, Black mustard
   ANTIDIABETIC	Gymnema
   LEUCODERMA	Psoralea, Ammi

2. On the Basis of Linkage of Glycone to Aglycone

   TYPE	DESCRIPTION	EXAMPLE
   C-glycosides	Sugar is connected to a carbon atom (aglycone-C-C₆H₁₁O₅)	Cascara, Aloe, Cochineal (carminic acid)
   O-glycosides	Sugar is connected to O or phenol group (aglycone-O-C₆H₁₁O₅)	Senna, Rhubarb
   S-glycosides	Sulphur of SH group is attached to the sugar (aglycone-S-C₆H₁₁O₅)	Sinigrin (from black mustard)
   N-glycosides	N of NH (amino group) is attached to the sugar (aglycone-N-C₆H₁₁O₅)	Nucleosides

3. On the Basis of Chemical Nature

   TYPE OF GLYCOSIDE	EXAMPLES
   ANTHRAQUINONE GLYCOSIDES	Senna, Aloe, Cascara, Rhubarb, Hypericum
   CARDIAC GLYCOSIDES	Digitalis, Strophanthus, Ouabain, Thevetia, Squill
   SAPONIN GLYCOSIDES - TETRACYCLIC TRITERPENOIDS	Dioscorea, Shatavari
   SAPONIN GLYCOSIDES - PENTACYCLIC TRITERPENOIDS	Ginseng, Liquorice, Senega, Sarsaparilla, Quillaia bark, Jalbrahmi, Safed musali, Momordica, Gokhru
   CYANOGENETIC GLYCOSIDES	Bitter almond, Wild cherry bark
   ISOTHIOCYANATE GLYCOSIDES	Black mustard, Sinigrin
   FLAVANOL GLYCOSIDES	Buckwheat, Gingko, Silymarin
   COUMARIN GLYCOSIDES	Ammi, Visnaga, Psoralea, Tonka bean, Mylabris
   ALDEHYDE GLYCOSIDES	Vanilla
   PHENOL GLYCOSIDES	Bear berry
   STEROIDAL GLYCOALKALOIDS	Solanum
   BITTER GLYCOSIDES	Gentian, Picrorhiza, Chirata

Test for Identification of Glycosides

Anthraquinone Glycosides

ALOES

1. General Tests: 1g of aloe powder is boiled with 10 ml water and filtered with kieselguhr.
   1. Bromine test: Freshly prepared bromine solution added to filtrate gives a pale yellow precipitate of tetrabromalin.
   2. Schoenteten's reaction (Borax test): Filtrate treated with borax, shaken till dissolved. Few drops added to water give a green fluorescence.
2. Special Tests:
   1. Nitrous acid test: Sodium nitrite crystals + acetic acid added to aqueous aloe solution.
      • Curacao aloes: Sharp pink to carmine colour.
      • Cape aloes: Faint pink colour.
      • Socotrine and Zanzibar aloes: Very less change in colour. (This test is due to isobarbaloin)
   2. Nitric acid test: Nitric acid directly applied to drug or its aqueous solution.
      • Curacao aloes: Deep brownish-red colour.
      • Cape aloes: Brownish colour changes to green.
      • Socotrine aloes: Pale brownish to yellow colour.
      • Zanzibar aloe: Yellowish brown colour.
   3. Cupraloin test (Klunge's isobarbaloin test): To very dilute aqueous aloe solution, add copper sulphate solution, sodium chloride, and excess 90% alcohol.
      • Curacao aloes: Wine red colour persisting for four hours.
      • Cape aloes: Faint colouration rapidly changing to yellow.
      • Socotrine aloes: No colour.
      • Zanzibar aloes: No colour.
   4. Modified anthraquinone test: (Indicates presence of C-glycosides). Aqueous aloe solution treated with ferric chloride and dilute hydrochloric acid for oxidative hydrolysis of aloe-emodin. Free anthraquinones collected in organic solvent (carbon tetrachloride/ether). Organic layer separated, shaken with dilute ammonia. Ammoniacal layer shows rose-pink to cherry red colour (indicating aloe emodin).

CASCARA

Contains C-glycosides, gives positive result for modified Borntrager's test.

RHUBARB

1. Gives positive result for modified Borntrager's test.
2. Shows red colour with addition of alkalies due to presence of anthraquinone glycosides.

SENNA

Borntrager's test employed for presence of anthraquinone in senna leaves.

Cardiac Glycosides

DIGITALIS

• Keller Kiliani test (to detect digitoxose sugar): 1gm Drug + 10 ml 70% Alcohol (2-3 min) → Extract + Lead acetate + FeCl₃ → Glacial acetic acid. Transferred to tube with 2 ml conc. H₂SO₄ gives Reddish green colour.
• Legal test: Solution of glycoside + pyridine + sod. Nitroprusside solution + NaOH solution forms red pink colour.
• Baljet test: Section of digitalis + Solution of Sodium Picrate gives Yellow or Orange colour.
• Raymond's test: Section of digitalis and 50% C₂H₅OH + 0.1 ml of m-nitrobenzene add 20% NaOH gives Violet colour.
• Kedde test: Section of digitalis + Kedde's reagent gives Blue or violet.
• Antimony trichloride test: Section of digitalis + Antimony trichloride and trichloroacetic acid forms Blue colour.

INDIAN SQUILL

1. Mesophyll stains red colour with alkaline colarin sol.
2. Reddish purple colour with 0.1 M iodine sol.

STROPHANTHUS

The glycosides show emerald green colour on addition of 80% sulphuric acid.

Saponin Glycosides

Common Test for Saponin Glycosides

• Foam test: Shake extract vigorously with water, produces foam.
• Haemolytic test: Extract + drop of blood placed on glass slide, Haemolytic zone appears.
• Liebermann test (Test for triterpenoid saponins): Extract + acetic anhydride + heat → Pink colour appears.

LIQUORICE

Section of drug + 80% H₂SO₄ gives deep Yellow Colour.

Cyanogenetic Glycoside

WILD CHERRY BARK

1. Sodium picrate test: Small pieces of bark in flask with water. Filter paper soaked in sodium picrate suspended at neck. Paper turns yellow to brick red due to liberated hydrocyanic acid (forms sodium isopurpurate).
2. The liberated hydrocyanic acid on hydrolysis reduces mercurous nitrate to metallic mercury.
3. Paper dipped in guaiacum resin, moistened with dilute copper sulphate. Exposed to freshly cut drug surface, produces blue stain.

Isothiocyanate Glycoside

MUSTARD SEED

When treated with alkali shows bright yellow colour.

Flavonoid Glycoside

Shinoda test: Drug + 5ml 95% ethanol + conc. HCl + 0.5 gm of magnesium gives Pink colour.

Coumarin Glycoside

PSORALEA

Hydro-alcoholic sol. of psoralen + propylene glycol + acetic acid gives blue fluorescence.

Bitter Glycosides

GENTIAN

Under UV radiation, gentian extract shows light blue fluorescence.

GUDMAR

1. Dilute solution anaesthetises sweet taste buds.
2. Gives copious foam after shaking with water, and on addition of dil. hydrochloric acid, voluminous precipitate.

Tannins

Properties of Tannins

• Soluble in water, alcohol, dil. alkalies, glycerine, and acetone but insoluble in organic solvents such as benzene, ether, and chloroform.
• Possess tanning properties.
• With ferric salt, they give blue, violet, or green colour.
• Precipitate with alkaloids and heavy metals; therefore, used as antidotes in alkaloidal and heavy metal poisoning.
• In aqueous solution, tannins produce acidic reaction and have an astringent taste.

Classification of Tannins Based on Chemical Nature

1. Hydrolysable tannins
2. Condensed tannins
3. Pseudotannins

1. Hydrolysable Tannins:

• Hydrolysed by acids or enzymes to produce gallic acid or ellagic acid.
• Chemically, they are esters of sugar (usually glucose) with one or more trihydroxybenzene carboxylic acid.
• With ferric chloride, they produce a blue colour, used in ink manufacturing.
• Examples: Gallotannin from rhubarb, chestnut, nutgall, clove; Ellagitannin from myrobalam of oak.

2. Condensed Tannins:

• Also called phlobatannins or proanthocyanidins. Related to flavonoids pigments, with polymeric formula flavone-3-ol.
• On treatment with acids or enzymes, decomposed into red insoluble compounds called phlobaphens.
• On heating, they produce catechol, thus also called catechol tannins.
• Drugs containing: cinchona bark, cinnamon bark, pale and black catechu, cocoa, kola seeds, etc.

3. Pseudotannins:

• Low molecular weight compounds.
• Do not respond to Goldbeater's skin test.
• Examples: Catechins from cocoa, chlorogenic acid from nuxvomica and coffee.

Test for Identification of Tannin

1. Goldbeater's skin test: Goldbeater's skin (ox intestine membrane) soaked with HCl, rinsed, added to tannin solution for 5 min, washed, then transferred to 1% ferrous sulphate solution. A brown black colour on the skin confirms tannins.
2. Phenazone test: 10 ml aqueous tannin extract + 1gm sodium acid phosphate. Warm, cool, filter. To filtrate add 2% phenazone solution. All tannins present are precipitated.
3. Gelatin test: To tannin solution add 1% gelatin solution containing 10% sodium chloride. A precipitate confirms tannins.
4. Test with ferric chloride solution: To tannin solution add ferric chloride solution. A blue, black, violet, or green precipitate or colour confirms tannins.
5. Match-Stick test: Dip match stick in plant extract, dry, moisten with conc. HCl, warm near flame. Wood turns pink or red (tannins + conc. HCl produce phloroglucinol, which reacts with lignin).

Volatile Oil

Properties of Volatile Oil

• Characteristic odors
• High refractive index
• Optically active
• Immiscible with water
• Soluble in ethers, alcohol, and most organic solvents.

Classification (Types of Volatile Oil)

Test for Identification of Volatile Oil

1. Salkowski test: Drug (mg) + CHCl₃ + H₂SO₄ gives Yellow colour which changes to red.
2. Noller test: 20 mg drug + ½ ml of (SnCl₂ in SOCl₂) → Red colour.
3. Antimony Trichloride test: Antimony trichloride in CHCl₃; dip filter paper soaked in this solution, in drug solution → spray with H₂SO₄ and acetic anhydride. Orange red colour is produced.

Resin

• Resins are formed in schizogenous or schizolysigenous ducts or cavities of the plant.
• Normal or physiological resin: Produced as a normal product of metabolism without plant injury.
• Abnormal or pathological resin: Produced by injury or wound to the plant (e.g., benzoin and tolu balsam).
• Resins are present in different parts of the plant (roots, rhizomes, fruits, seeds, trunk, flowers, fruiting tops, etc.).
• Normally used as antiseptics, carminative, purgative, expectorant, and analgesic.
• Resins are also obtained from animals (e.g., shellac).

Properties of Resins

1. All resins are heavier than water; they are usually amorphous, hard, and brittle solids.
2. They are insoluble in water and usually insoluble in petroleum ether.
3. Chemically, resins are complex mixtures of resin acids, resin alcohols (resinols), resin phenols (resinotannols), esters.
4. Chemically inert compounds known as resenes.
5. Many resins, when boiled with alkalies, yield soaps.
6. By the action of heat, they soften, yielding clear, adhesive fluids. Resins burn with a characteristic, smoky flame.

Classification of Resins

Resins are also further classified into:

• Resins: colophony, cannabis.
• Oleoresins: copaiba, ginger.
• Oleo-gum-resins: asafoetida, myrrh.
• Balsams: balsam of Tolu, balsam of Peru.
• Glycoresins: jalap.
• Resenes: Asafoetida, colophony.

Test for Identification of Resins

Resources & Downloads

Embedded PDF Preview