This document discusses adulteration and quality control of herbal drugs. It defines adulteration as substituting or mixing an herbal drug with inferior substances. There are two main types of adulteration - deliberate and accidental. Common reasons for adulteration include scarcity or high price of drugs. The document then describes various types of adulteration like inferiority, spoilage, deterioration, admixture, and substitution. It also discusses different methods of adulteration and quality evaluation of herbal drugs through morphological, microscopic, physical, chemical and biological methods. Standardization of herbal medicines ensures quality, efficacy, safety and reproducibility.

1. Adulteration and Quality Control of Herbal Drugs
By
Dr. Rakesh Barik

2. Practice of substituting original crude drug partially or whole with
other similar looking substances but the latter is either free from or
inferior in chemical and therapeutic properties.
Debasement of an article.
Admixture or substitution of original or genuine drug with
inferior, defective or otherwise useless or harmful
substances.
Adulteration

3. • Deliberate ( Intentional ) adulteration
• Accidental ( In-deliberate) adulteration
Types of Adulteration
Reasons for Adulteration
• Scarcityof the drug
• Thehigh priceof the drug in the market, eg: Clove,Cinnamon,
Cardamom
• It is very common with the contraband drugs.e.g.Opium

4. Types of Adulteration
Inferiority
Spoilage
Deterioration
Admixture
Sophistication
Substitution

5. Inferiority
Natural substandard condition (e.g. where a crop is taken
whose natural constituent is below the minimum standard for
that particular drug) which can be avoided by more careful
selection of the plant material.
Spoilage
Substandard condition produced by microbial or other pest
infestation which makes a product unfit for consumption,
which can be avoided by careful attention to the drying, and
storage conditions.

6. Deterioration
Impairment of the quality or value of an article due to destruction
of valuable constituents by bad treatment or aging or deliberate
extraction of the constituents and the saleof the residue asthe original
drugs.
Admixture
Addition of one material to another by accident, ignorance or
carelessness. Eg. Mixing soil with any underground powdered drug,
simultaneouscollectionoftwospecies,etc.

7. Sophistication
Deliberate addition of spurious or inferior material with intent
to defraud; such materials are carefully produced and may
appear at first sight to be genuine e.g. powder ginger may be
diluted with starch with addition of little coloring material to
give the correct shade of yellow colour.
Substitution
Addition of an entirely different article in place of that which is
required e.g. supply of cheap cottonseed oil in place of olive
oil.

8. Methods of Adulteration
•Substitution with inferior commercial varieties.
•Adulteration by Artificially Manufactured Substitutes
•Substitution by exhausted drugs
•Substitution by Superficially Similar but Cheaper Natural
Substances
•Adulteration by addition of worthless heavy materials
•Addition of SyntheticPrinciples
•Usageof Vegetative Matter from the Same Plant

9. Substitution with Inferior CommercialVarieties
Due to morphological resemblance to the authentic drugs, different
inferior commercial varieties are used as adulterant which may or
may not have any chemical or therapeutic potential asthat original
naturaldrug.
Eg. Indian Senna (Cassia angustifolia ) and Dog Senna (Cassia
obovata ) have been used to adulterate Senna (Cassia senna),
Japanese ginger ( Zingiber mioga ) to adulterate medicinal ginger
(Zingiber officinale), etc.
Adulteration byArtificially Manufactured Substitutes
To provide the general form and appearance of various drugs, some
materials are artificially manufactured and are used as substitute of
the original one. E.g. artificial invert sugar for honey; paraffin wax
after yellow coloration substituted for bees wax.

10. Substitution by ExhaustedDrugs
The same plant material is mixed which is having no active
medicinal components as they have already been extracted out.
This practice is most common in case of volatile oil containing
materials like clove,fenneletc.
Substitution by Superficially Similar but Cheaper Natural
Substances
The adulterated product has no relation with the genuine article,
may or may not have any therapeutic or chemical component
desired. Exhausted materials resemble the original materials.
Eg. Sometimes when coloring matters have been extracted or
removed during exhaustion, the residue is re-colored with
artificial dyes as is done with saffron and red rose petals.

11. Adulteration byAddition of Worthless Heavy Materials
A large mass of stone mixed with Liquorice root, pieces of limestone
are found in Asafoetida and lead shots in pieces of opium etc.
Addition of Synthetic Principles
Sometimes to fortify inferior natural products, synthetic principles are
added e.g. adding citral to oil of lemon; benzyl benzoate to balsam of
Peru etc.
Usage of Vegetative Matter from the Same Plant
Mixing adventitious matters or naturally occurring substances with the
drug in excessive amount or parts of plant other than that which
constitutes the drugs. Eg, liver worts and epiphytesgrowing in bark
mixed with Cascara or Cinchona; stems of buchu are cut and added to
the drug.

12. 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.
Hence they are capable of variation. This variability is also caused by
differences in growth, geographical location, and time of harvesting.
Standardization of herbal medicines is the process of prescribing a set of
standards or inherent characteristics, constant parameters, definitive
qualitative and quantitative values that carry an assurance of quality,
efficacy, safety and reproducibility.
It is the process of developing and agreeing upon technical standards.
Specific standards are worked out by experimentation and observations,
which would lead to the process of prescribing a set of characteristics
exhibited by the particular herbal medicine.

13. Drug evaluation may be defined as the determination of identity, purity
and quality of a drug.
(1) Identity – identification of biological source of the drug.
(2) Quality – the quantity of the active constituents present.
(3) Purity – the extent of foreign organic material present in a crude drug.
Problems that influence the quality of herbal drugs.
1. Herbal drugs are usually mixtures of many constituents.
2. The active principle(s) is (are), in most cases unknown.
3. Selective analytical methods or reference compounds may not be available
commercially.
4. Plant materials are chemically and naturally variable.
5. Chemo-varieties and chemo cultivars exist.
6. The source and quality of the raw material are variable.

14. The methods of harvesting, drying, storage, transportation,
and processing (for example, mode of extraction and polarity
of the extracting solvent, instability of constituents, etc.) also
affect herbal quality.
According to WHO (1996a and b, 1992), standardization and
quality control of herbals is the process involved in the
physicochemical evaluation of crude drug covering aspects,
such as selection and handling of crude material, safety,
efficacy and stability assessment of finished product,
documentation of safety and risk based on experience,
provision of product information to consumer and product
promotion.

15. Methods of Drug Evaluation:
 The evaluation of a drug is done by studying its
various properties.
 The various types of evaluation are :
(1) Morphological evaluation
(2) Microscopical evaluation
(3) Biological evaluation
(4) Chemical evaluation
(5) Physical evaluation
(6) Toxicological evaluation.

16. 1. MORPHOLOGICAL EVALUATION (Organoleptic):
Drug evaluation by means of our sense organs like
odour, taste, smell.
Study of Gross Morphology:
• It includes the visual examination of drug.
• These drugs are classified into the following groups.
 Underground structures
 Leaves
 Flowers
 Fruits
 Seeds
 Herbs

17. Study of Sensory Characters:
• Colour, Texture, Odour and Taste are useful in the evaluation
of drugs.
 Colour:
• Some drugs are green in colour when dried in shade.
• But they become pale and bleached when dried in
sunlight.
 Odour:
• Mentha, clove are some of the examples for the drugs which
have a distinct odour.
 Taste:
•The drugs may be evaluated by taste
Ex: Ginger, capsicum

18. II. Microscopic or Anatomical Evaluation:
• This method allows a more detailed examination of a drug
and it can be used to identify organised drugs by their
known histological characters.
• Qualitative : Section study: T.S., L.S., W.M. Histochemical
tests. POWDER STUDY.
• Quantitative: Camera Lucida
 Stomatal Number
 Stomatal Index
 Vein-islet Number
 Vein Termination Number
 Palisade Ratio

19.  Stomatal Number:
• The average number of stomata present per square
millimeter of the epidermis is known as stomatal
number.
• Example: Datura – 141 (upper epidermis)
• Stomatal number varies considerably with the age of
the leaf but stomatal index is relatively constant for a
given species.
• Example: Atropa – 20.0-23.0 (lower epidermis)

21. Vein-islet Number:

22. Palisade Ratio

23. Vein Termination Number

25. •25mg of drug powder and 50mg of Lycopodium spore were mixed using a small
flexible spatula with little suspending liquid (i.e. Corn oil).
•This mixture was incorporated with sufficient quantity of corn oil until a smooth
paste was formed.
•The mixture was then transferred to a stopper tube by washing with excess of corn
oil and volume of the stopper tube was fixed (4ml).
•The stopper tube was oscillated gently in order to obtain uniformity.
•One drop of this suspension was placed in microscopic slide, and spread using
glass rod.
•Cover slip was applied and was kept aside in a plane surface for few minutes in
order to settle the fluid.
•The number, area, length and breadth of identifying character were counted in each
of 25 different fields.
• Then 50mg, 75mg and 100mg of drug powder with 50mg of Lycopodium spore
were made into suspension as above and the number, area, length and breadth of
identifying character were counted in each of the 25 different fields.

27. PHYSICIAL EVALUATION:
• All the physical properties are useful in detection of
constituents present in a plant or herbal drug.
• A few of them are:-
 Moisture Content
 Viscosity
 Melting point
 Optical Rotation
 Refractive Index
 Ash Values
 Extractive values
 Volatile oil Content
 Foreign organic matter

28. Loss on drying.
It is the loss of mass expressed as percent w/w.
The test for loss on drying determines both water and volatile
matter in the crude drug.
Moisture is an inevitable component of crude drug, which must
be eliminated as far as possible.
An accurately weighed quantity (1.5 g) of powdered drug was
taken in a tared porcelain dish.
The sample was kept in the oven at a temperature 105°C for 2
hrs.
Then it was cooled in a desiccator to room temperature, the
procedure was repeated till constant weight is observed..
Moisture Content

29.  Viscosity:
• Viscosity of a liquid is constant at a given
temperature and is an index of its
composition.
• Hence, it is used as a means of standardising
liquid drugs.
• Cup and Bob Viscometer, Ostwald Viscometer
• Example:
Liquid paraffin – less than 64 centistokes.

30. Melting Point:
• It is one of the parameters to judge the
purity of crude drugs containing lipids as
constituents.
• They may of animal or plant origin and
contain fixed oils, fats and waxes.
• The purity of the following crude drugs can
be ascertained by determining their
melting points in the range shown against
each of them
• Example: Coca butter (30⁰ - 33⁰C)

31.  Ash Values: Determination of inorganic impurities. Sand,
silicates, etc. Muffle Furnace, crucible – silica.
Total ash value : Total amount of material remaining after
ignition. This includes both “ physiological ash”, which is
derived from the plant tissue itself, and “ non-
physiological” ash, which is the residue of the extraneous
matter (e.g. sand and soil) adhering to the plant surface.
Acid Insoluble Ash value: Residue obtained after boiling
the total ash with dilute HCl, and igniting the remaining
insoluble matter. This measures the amount of silica
present, especially as sand and siliceous earth.
Water soluble ash value: Difference in weight between
the total ash and the residue after treatment of the total
ash with water. Ex : amla –not more than 5% opium – not
more than 6 %

32.  Extractive values:
• Amount of active constituents extractable into
the given amount of solvent.
• Water, alcohol or ether soluble extractive
values are determined for evaluation of such
drugs.
• Cold maceration method or boiling method.

33. Foreign Matter and its Determination:
Medicinal plant materials should be entirely free from visible signs of
contamination by insects and other animal contamination etc. No
abnormal odour, discoloration, slime or signs of deterioration should be
detected. Sample size: Roots, rhizomes and bark – 500g Leaves,
flowers, seeds and fruit – 250g The foreign matter should be detected
by inspection with the unaided eye or by the use of a lens. Separate and
weigh it and calculate the percentage present.
Determination of Moisture content:
An excess of water in medicinal plant materials will encourage
microbial growth, the presence of fungi or insects, and deterioration
following hydrolysis. Limits for water content should therefore be set
for every given plant material. This is especially important for
materials that absorb moisture easily or deteriorate quickly in the
presence of water.

34. Determination of volatile oil in drugs:
Volatile oils are characterized by their odour, oil-like
appearance and ability to volatilize at room temperature.
Chemically, they are usually composed of mixtures of for
example, monoterpenes, sesquiterpenes and their oxygenated
derivatives. Aromatic compounds predominate in certain
volatile oils, because they are considered to be the essence of
the plant material, and are often biologically active, they are
also known as essential oils.
The determination of volatile oil in a drug is made by distilling
the drug with a mixture of water and glycerin, collecting the
distillate in a graduated tube in which the aqueous portion of
the distillate is automatically separated and returned to the
distilling flasks, and measuring the volume of the oil. The
content of the volatile oil is expressed as a percentage v/w.

35. Chemical Evaluation :
chemical tests are carried out using various
chemical reagents to identify the nature and
quality of chemical constituents of crude
drugs.
chemical tests may be qualitative or quantitative .
Various qualitative chemical tests :
i. Carbohydrates – molisch test
ii. Proteins – biuret test
iii. Alkaloids – mayers test
iv. Tannins – gelatin test

36. Instrumental methods:
• They make use of various instruments
for evaluation like colorimetry,
flourimetry spectrophotometry etc.
Chemical constants tests:
• These are like acid value, iodine value
and ester value etc are used for the
identification of fixed oils and fats.

37.  Individual chemical tests:
• These are the tests which are used for
identifying particular drugs.
• Examples: Halpher’s test for cotton seed oil.
 Microchemical tests:
• These are the tests which are carried on
slides.
• Example: Eugenol in clove oil is precipitated as
potassium eugeinate crystals.

38. Biological Evaluation :
It is employed when the drug cannot be evaluated
satisfactorily by chemical and physical methods.
a) Determination of bitterness value
b) Determination of haemolytic activity
c) Determination of swelling index
d) Determination of foaming index

39. Determination of foaming index:
Many Medicinal plant materials contain saponins that can cause a
persistent foam when an aqueous decoction is shaken. The foaming
ability of an aqueous decoction of plant materials and their extracts is
measured in terms of a foaming index.
Determination of Haemolytic Activity:
Many medicinal plant materials, especially those derived from the
families Caryophyllaceae, Araliaceae, Sapinaceae, Primulaceae, and
Dioscoreaceae contain saponins. The haemolytic activity of plant
materials, or a preparation containing saponins, is determined by
comparison with that of a reference material, saponin, which has a
haemolytic activity of 1000 units per gm. A suspension of
erythrocytes is mixed with equal volumes of a serial haemolysis and
is determined after allowing the mixtures to stand for a given period
of time. A similar test is carried out simultaneously with saponin.

40. Determination of Bitterness Value:
Medicinal plant materials that have a strong bitter taste are employed
therapeutically, mostly as appetizing agents. Their bitterness stimulates
secretions in the gastrointestinal tract, especially of gastric juice. Bitter
substances can be determined by taste. However, since they are mostly
composed of two or more constituents with various degrees of bitterness, it
is first necessary to measure total bitterness by taste.
The bitter properties of plant material are determined by comparing the
threshold bitter concentration of an extract of the materials with that of a
dilute solution of quinine hydrochloride.
The bitterness value is expressed in units equivalent to the bitterness of a
solution containing 1 gm of quinine hydrochloride in 2000ml. Safe drinking
water should be used as a vehicle for the extraction of plant materials and for
the mouth wash after each tasting. Taste buds dull quickly if distilled water
is used. The hardness of water rarely has any significant influence on
bitterness.

41. Determination of swelling index:
Drugs containing Mucilage
Take 1g of isapgol seeds in a measuring
cylinder and add 25 ml of water and allow it to
stand for 24 hrs and measure the difference of
intial height and the height after 24hrs . The
difference in the heigt gives the swelling factor
of isapgol seeds .

42. Toxicological evaluation:
a) Determination of arsenic and heavy metals
b) Determination of pesticide residues
c) Determination of micobial contaminants
d)Radioactive contamination
Few examples and limits are
 Arsenic: max 1.0 ppm
 Lead : max 10.0 ppm
 Cadmium : max 0.3 ppm

43. Determination of Pesticide Residues:
Limits for pesticide residues should be established following the
recommendations of the Food and Agriculture Organization of the United
Nations (FAO) and the World Health Organization (WHO) which have
already been established for food and animal feed. These recommendations
include the analytical methodology for the assessment of specific pesticide
residues .
Pesticides residue are any particular substance in food, agriculture
commodities or animal feed resulting from the use of a pesticides. Herbal
drugs are prone to contain pesticide residue, which gather from agricultural
practices, such as Spraying, behaviour of soil during cultivation and addition
of fumigants during storage. The Pesticides contain chlorine in the
molecules, which can be determined by analysis of chlorine, insecticides
containing phosphate can be detected by measuring total organic phosphorus.
The various methods are used to measure pesticides by GC, MS, OR GCMS.
Some simple methods are also published by the WHO and European
pharmacopeia has in general limits for pesticides residue in medicine