Unit 1. C. Quality Control of Drugs of Natural Origin | Adulteration & Evaluation of Crude Drugs | Pharmacognosy and Phytochemistry Unit 1 | B.Pharm Semester IV

Pharmacognosy and Phytochemistry-I
Unit 1.C : Quality Control of Drugs of Natural Origin
Class : IV Semester B. Pharm
Presented by:
Ms. Asha Golasangimath
Assistant Professor
Department of Pharmacognosy
Alva’s College of Pharmacy, Moodubidire
Affiliated to RGUHS, Karnataka
Academic Year: 2025–2026

Alva's College of Pharmacy, Moodubidire 2

Alva's College of Pharmacy, Moodubidire
3
*Adulteration
Adulteration is practice of substituting
original crude drug partially or wholly
with other spurious substances which
reduces their chemical and therapeutic
properties.
Admixture or substitution of original or
genuine drug with inferior, substandard,
useless or harmful substances.
An adulterated drug is a substance that
does not have the quality, strength, or
purity that it is supposed to have. It
may contain harmful substances or be
contaminated with other substances that
can cause harm to the person taking it.

Causes of adulteration
a. Confusion in vernacular names
b. Lack of knowledge about
authentic source
c. Similarity in morphology
d. Lack of authentic plant
e. To get profit
f. To get more quantity
g. Due to the high price of crude
drug
h. To fulfill the public demands
i. Improper storage
DISADVANTAGES OF
ADULTERATION
- It leads to damage of
dosage forms
- leads to deterioration
of product
- may cause a death of
patient
- lead to the altering the
drug nature
- may cause a unwanted
side effects in patient

Factors / conditions that create Adulteration
 Inferiority: it is a natural substandard condition, which can be avoided by more careful
selection of the plant material.(lesser active constituents than required)
Ex : The seeds of Strychnos nux-vomica containing less than 1.5% of Strychnine would be
considered as inferior or substandard drug.
 Spoilage : it is substandard condition produced by a microbial or other pest infection,
which makes a product unfit for consumption, which can be avoided by careful attention to
the drying, and storage conditions.
 Deterioration : it is an impairment of the quality due to aging and removal of active
constituents from drugs.
Ex : Portion of volatile oil is removed from clove which decrease the quality of clove.
 Admixture : it is the addition/ or mixing of unwanted materials with the genuine drug
accidentally or intentionally.
Ex: Clove Is Added Along with clove stalks.
Adding of Soil and Stone Pieces to The Roots and Rhizomes Unintentionally.
 Substitution :It occurs when totally different substance is used or sold in place of
original drug. All types of substitution are considered legally as adulteration.
Ex: cotton seed oil sold as olive oil .

Adulteration may take place by two ways
1. Indirect or unintentional Adulteration
2. Direct or intentional Adulteration

TYPES OF ADULTERATION
1. Substitution with sub-standard commercial varieties
2. Substitution with superficially similar inferior drugs
3. Substitution with artificially manufactured substance
4. Substitution with exhausted drugs
5. Use of synthetic chemicals
6. Presence of vegetative matter from the same plant
7. Harmful adulterants
8. Adulteration of powders

1. Substitution with sub-standard commercial
varieties:
- The original drugs are substituted using inferior quality drugs that may
be similar in morphological characters, chemical constituents or
therapeutic activity.
- Most common practice of adulteration
- Eg. -Hog gum or hog tragacanth for tragacanth gum,
- Indian senna substituted with Arabian senna
- capsicum minimum replaced by capsicum annuum

2. Substitution with superficially similar inferior
drugs
- These inferior drugs used may or may not be having any chemical or
therapeutic value as that of original natural drug.
- Have morphological resemblance to authentic drug.
- Eg
- Mother clove and clove stalk are mixed with cloves
- Bees wax is substituted by japan wax

3. Substitution with artificially manufactured
substance
- Substance prepared to resemble original drug are used as substitutes.
- This practice is done for costlier drugs.
- Eg. - paraffin wax made yellow colored and substituted for
beeswax.
- compressed chicory in place of coffee.
coffee chicory
coffee

4. Substitution with exhausted drugs
- The same drug is admixed but is devoid of any medicinally active constituents
as they are already extracted out.
- Common in case of volatile oil containing drugs like fennel, clove, coriander,
etc..
- some natural characters like color and taste are manipulated by adding other
additives and then substituted.
- Eg.- Artificial coloring (maize/corn silk) of saffron.

* 6. Use of synthetic chemicals
5. Use of synthetic chemicals
Synthetic Substances Are Used in Place of Original Crude Drugs -
They Are Prepared Based on Their Therapeutics Properties.
- E.g.- Citral In Place of Lemon Oil and adulterated olive oil
- adding chemicals to get faster yield.

6. Presence of vegetative matter from same plant
- Other plants growing with medicinal plants having same appearance.
- odour and same chemical constituents are used as adulterants.
- Eg. The Stem Portions of a Certain Leaf Drugs Are Mixed Together.
- Lower plants like moss, liver worts are growing on bark portion are
mixed with cinchona.

7. Harmful adulterants
- waste from market are collected
and mixed with authentic drugs.
- particularly noticed for liquid
or unorganized drugs.
- Eg. Hard Woods Are Used as
Adulterants for Liquorice Root
- opium with lead shots
- cocoa butter mixed with
paraffin

8.Adulteration of powders
- Powdered forms are frequently adulterated.
- Eg. – Turmeric powder with colour or starch.
- Powdered liquorice mixed with powdered olive stones.

*
*Evaluation of crude drugs is the process of determining the identity, purity, quality, and
strength of a drug
*Evaluation is the systematic study of crude drugs to detect adulteration and ensure
quality and therapeutic efficacy.
WHY EVALUATION OF CRUDE DRUG IS NECESSARY?
*Authentication and Identification of crude drugs
*Detection of adulteration
*Assurance of purity and quality
*Determination of potency
*Standardization of drugs
*Ensures safety and therapeutic efficacy
*To check biochemical variation in the drug.
*Deterioration due to treatment in storage.

Evaluation of crude drugs by different methods
Organoleptic Microscopic Physical Chemical Biological

*Evaluation of the drugs by using sense organs(eye, tongue, nose, ear,
skin).
*Morphological evaluation of crude drugs include the parameters like
colour, odour, taste, size, shape, texture, fracture.
*Examples:
*Clove → Aromatic odor
*liquorice → Sweet taste
*Cinnamon → Characteristic odour

*Identification of drugs by studying cellular structures under microscope.
*They can be identified microscopically by cutting a thin TS(transverse section) or
LS(longitudinal section) and staining them with proper staining agent (starch is
identified by blue colour with iodine solution).lignified tissues give pink stain
with phloroglucinol and HCl .
*Microscopy also include the quantitative aspects like stomatal number and index,
palisade ratio, vein-islet number, size of starch grains, length of fibres etc.
*This method is used for Detecting adulteration, Identifying powdered drugs,
Studying tissues
The parameters observed in microscopic evaluation are:
*Starch grains
*Calcium oxalate crystals
*Trichomes
*Fibers
*Xylem vessels
*Stomata

*The physical evaluation is the Determination of physical constants of crude
drugs include parameters like :
* Moisture content
* Viscosity
* Melting point
* Solubility
* Swelling index
* Foaming index
* Refractive index
* Optical rotation
* Ash Values (Total ash, Acid insoluble ash, Water soluble ash, Sulphated ash)
* Extractive Values (Alcohol soluble extractive, Water soluble extractive)
* Volatile oil content
*Purpose:
Determines amount of active constituents extracted by solvents.

Parameter Definition Standard Value / Range Example
Moisture Content
Amount of water present in crude
drug.
Usually 5–14% (depends on drug)
Digitalis not more thn
5.3%
Viscosity Resistance of liquid to flow. Varies with drug and temperature
Acacia mucilage< 64
centistokes
Melting Point
Temperature at which solid
changes to liquid.
Specific for each substance
Cocoa butter: 30–
35°C
Solubility
Ability of substance to dissolve in
solvent.
Expressed as soluble/slightly
soluble/insoluble
Gum acacia in water
Swelling Index
Volume increase after absorbing
water.
Minimum value specified in
pharmacopoeia
Isabgol: ≥10 mL/g
Foaming Index
Ability to produce foam due to
saponins.
Usually <100, 100–1000, or >1000 Liquorice
Refractive Index
Measure of bending of light
through substance.
Fixed value for oils/liquids Clove oil: 1.53–1.54
Optical Rotation Rotation of plane polarized light. Specific positive or negative range
Peppermint oil: −10°
to −30°
Total Ash
Total inorganic residue after
incineration.
Usually <5–10% Ginger 6%
Alcohol/ water
Soluble Extractive
Constituents soluble in
alcohol/water.
Specific % value for each drug Ginger: ≥3–5%
Volatile Oil Content Amount of volatile oil present. Specific % depending on drug Clove: ≥15% oil

*Chemical Evaluation is based on chemical constituents present in drugs.
*Qualitative methods are used to determine identity n purity of crude drugs.
*The isolation, identification and purification of active constituents is based
on chemical method of evaluation.
*Chemical Methods
• Color reactions
• Chemical tests
• Chromatography (TLC, HPTLC, HPLC) (Separation of different components)
• Spectroscopy (Identification of compounds) (UV-vis, NMR, IR)

*
Chemical Constituent Test Positive Observation
Alkaloids
Dragendorff’s Test Orange-red precipitate
Mayer’s Test Cream precipitate
Wagner’s Test Reddish-brown precipitate
Glycosides
Keller–Killiani Test Brown ring formation
Legal’s Test Pink to red color
Borntrager’s Test Pink/red color
Tannins
Ferric Chloride Test Blue-black/green color
Gelatin Test White precipitate
Flavonoids
Shinoda Test Pink/red color
Alkaline Reagent Test Yellow color
Saponins
Foam Test Persistent froth
Hemolysis Test Hemolysis of RBCs
Carbohydrates
Molisch’s Test Violet ring
Fehling’s Test Brick red precipitate
Proteins
Biuret Test Violet color
Xanthoproteic Test Yellow color
Steroids/Terpenoids Salkowski Test Reddish-brown color
Liebermann–Burchard Test Green/blue color

*Biological Evaluation: drugs have biological or pharmacological activities
due to the chemical constituents present in it. For evaluation experiments
are carried out on animals or by bioassays.
*Biological evaluation is the method of determining the activity, potency and
toxicity of crude drugs using living organisms, tissues or microorganisms.
Biological evaluation is important:
*When the chemical nature of the drug is not known,
*If the quantity of the drug is very less and cannot be evaluated chemically and,
*Some of the drugs have same chemical constituents but different biological
activities.
*Compare standard and sample

Crude Drug
↓
Biological Testing
↓
Animals / Microorganisms / Tissues
↓
Observation of Response
↓
Determination of Potency & Safety
Importance of Evaluation
*Determines potency
*Evaluates safety
*Confirms biological activity
*Detects toxicity
*Supports standardization

References
1. Text book of pharmacognosy by c. k. kokate, Purohit, Gokhale,
4th edtion, Nirali Prakasshan, 1996.
2. Pharmacognosy – G.E. Trease and W.C. Evans.
3. Pharmacognosy – Brady Tyler, Robbers
4. Adulteration — vikaspedia
5. Detection of food spoilage and adulteration by novel
nanomaterial-based sensors - pubmed (nih.Gov)
6. Foster s. A brief history of adulteration of herbs, spices, and
botanical drugs.Herbalgram, 2011; 92: 42-57.
7. Textbook of pharmacognosy & phytochemistry by biren shah,
a.K. Seth, page 107- 109

Unit 1. C. Quality Control of Drugs of Natural Origin | Adulteration & Evaluation of Crude Drugs | Pharmacognosy and Phytochemistry Unit 1 | B.Pharm Semester IV

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