The document provides guidelines on standardizing herbal medicines according to WHO parameters. It discusses the need for standardization due to biological and geographical variations in herbal drugs. Various physical, chemical, biological and microscopic parameters are described for evaluating the identity, purity, quality and strength of herbal medicines. Parameters like ash value, extractive value, thin layer chromatography, chemical tests etc. are used to develop a chemical fingerprint of each herbal drug. The guidelines aim to promote the safe and effective use of herbal medicines.

2. W.H.O.GUIDELINES
Herbal medicine is being used by about 80%
of the World population for primary health care.
They have faith, cultural acceptability and
being natural believed to have better
compatibility with the human body.

3. • Major Goals and Objectives of the WHO
Guidelines are
• To promote the appropriate ,safe and effective
use of herbal medicines and to encourage the
integration of herbal medicines into the
mainstream of medical systems

4. • A WHO guideline involves polices on Quality,
Safety and Efficacy assessment of crude plant
materials and stability of finished products.
• It is also giving a lot of emphasis on
documentation of traditional use of its activity
determination ( animal , human) and safety based
on experience or/toxicology studies

5. DEFINATION
Drug evaluation is defined as the determination
of identity, purity and quality of a drug.
Identity means the identification of drugs.
Quality means the quantity of active
constituents.
Purity means the extent of foreign material
present.

6. NEED OF STANDERDIZATION
1. Biochemical and Geographical variation in the drug
2. Deterioration during treatment and storage.
3. Substitution and adulteration
4. Export of quality of natural drugs
5. Popularity of natural drugs for primary care in
developing countries

7. 6. Herbal medicines ,however are not necessary always safe
simply because they are natural. Some have given rise to
serious adverse reactions and some contain chemicals that
may produce long term side effects such as Carcinogenicity
and Hepatotoxicity.
7. Also herbal medicine will only benefit the health of human
beings when they of good quality
8. Furthermore with increased use of both herbal medicine
and modern western pharmaceutical drugs, there is a
need to monitor interactions

8. SIGNIFICANCES OF DRUG EVALUATION
1. It is helpful for the detection of adulterants, if it is
adulterated.
2.It is also helpful to detect the presence of chemical
constituents present in the crude drug.

9. WHO PARAMETERS FOR STANDARDIZATION OF HERBAL
RAW MATERIAL, EXTRACTS AND THEIR PRODUCTS
(METHODS OF DRUG EVALUATION )
1. Preliminary evaluation
2. Morphological evaluation
3. Microscopical evaluation.
4. Physical Qualitative evaluation
5. Physical Quantitative evaluation
6. Chemical evaluation
7.WHO Biological evaluation
8. Toxicogical evaluation
9. Pharmacological evaluation
10. Analytical evaluation

10. Physical Qualitative evaluation
1. Melting point
2.Solubility
3.Optical rotation
4.Viscosity
5. Refractive index
6. Boiling point
7. Chromatographic
8.Spectroscopic evaluation

11. MELTING POINT
• In case of pure chemicals or phytochemicals
melting points are very sharp and constant.
• Since the crude drugs from animal or plant origin
contain the mixed chemicals , so they are
described with certain range of melting points.
• Colophony – 75- 85 , Beeswax - 62 - 65
• Wool fat - 34 - 40

12. SOLUBILITY
• The presence of adulterant in a drug could be
indicated by solubility studies
• Eg ; Castor oil is soluble in 3 volumes of 90%
alcohol , while adulterated form may show good
solubility in alcohol

13. OPTICAL ROTATION
• Certain drugs are found to have the property of rotating
the plane of polarized light in the pure state or in
solution . Thus, they are described to be optically
active and this property is known as optical rotation.
• Dextro - rotatory - towards right ( + ), Leavo- rotatory -
towards left ( - )
• Optical rotation is determined at 25˚C degree using
sodium lamp as the source of light.
• Example -
• Caraway oil - + 70˚ to 80˚
• Honey - +3˚ to 15˚

14. REFRACTIVE INDEX
• When a ray of light passes from one medium to
another of different density , it bent from original
path.
• Depending upon purity , it is constant for a liquid
and can be considered as one of the criteria for its
standardization .
• Examples – Arachis oil – 1.4678- 1.4698
• Caraway oil – 1.4838-1.4858

15. CHROMATOGRAPHY
• THIN LAYER CHROMATOGRAPHY
• Here comparison of retention factor values ( Rf )
with standards ascertain qualitative evaluation of
constituents
Rf values –
Example:
Eugenol- 0.47
Caravone - 0.46
Borneol - 0.24

16. THIN LAYER CHROMATOGRAPHY
• THIN LAYER CHROMATOGRAPHY
• Here comparison of retention factor values (Rf)
with standards ascertain qualitative evaluation of
constituents
Rf values –
Example: Eugenol- 0.47
Caravone - 0.46
Borneol - 0.24

18. SIGNIFICANCE:
1. The method is generally used to test the purity and
to determine concentration of the drug
2. When the quantity of the drug /sample are very
less then the drugs are evaluated by spectroscopic
methods

19. SPECTROSCOPIC EVALUATION
• 1. Colorimetric method
• 2. Fluorimetric method
• 3. Spectrophotometric method
• 4. I.R. Spectrophotometric method
• 5. NMR Spectroscopy
• 6. Mass Spectroscopy

20. PRINCIPLE :
• The capacity of certain molecules of a drug to absorb
vibration at a specific wavelength is the basis for the
drug evaluation

21. • Procedure :
• For the quantitative evaluation of a substance a
standard curve is first prepared by measuring the
O.D of a series of standard solutions of the pure
compound using light of a suitable wavelength ,
usually that at which the compound gives an
maximum absorption.
• The O.D of the solution to be evaluated is then
determined & its composition ascertained from the
standard curve.

22. 1. COLORIMETRIC METHOD
• It also called as Visible spectrophometry
• Visible region is from 380-780nm
• Most of the chemical compounds give characteristic
color with specific reagent
• The intensity of color in many cases are directly
proportional to the amount of concentration present

23. • Such compounds are estimated by colorimetry at a
suitable wavelength
• Eg : Ephedrine treated with Ninhydrine reagent forms
violet color , the intensity is measured at 550 nm.
• Ergot (Total alkaloids) when treated with p-dimethyl
amino benzaldehyde reagent (PABA) forms violet
color , the intensity is measured at 550 nm.

24. 2. FLUORIMETERIC METHOD
• The instrument used is Fluorimeter
• Some compounds produces fluorescence when
treated with specific reagent
• The intensity of the fluorescence is directly
proportional to the concentration of drug present
• The intensity of the fluorescence is measured by
Fluorimeter.
• Eg: Quinine when treated with 0.1 N Sulphuric acid
produces blue fluorescence the intensity is
measured at 450 nm

25. 3.U.V.SPECTROSCOPIC METHOD
• It is also called as U.V. Spectroscopy , U.V.region
from 185-380 nm
• Some compounds having the capacity to absorb
vibrations at specific wavelengths
• The intensity is measured by using
Spectrophotometer
• Eg : Papaverine in 0.1N Hcl ,the concentration of the
drug is measured at 310nm
• Eg : Strychinine in 0.1N Hcl , the concentration of the
drug is measured at 254nm

26. 4. INFRARED SPECTROSCOPY (IR)
• It is also known as I.R.Spectroscopy
• The region from 1430-910 cm- 1 is finger print region
• The constantly vibrating molecules stretch and
bend their bonds with respect to one another , by
absorbing infrared light
• Functional groups can be identified

27. • OH- group absorbs at 3200 - 3600 cm- 1
• C-H- group absorbs at 3100 - 2800 cm- 1
• Carbonyl group at 1700 - 1800 cm- 1 etc

28. 5.NUCLEAR MAGNETIC RESONENCE
• It is also called as NMR
• It is also called as H NMR and C NMR
• By this number of protons and carbons can be predicted
from spectrum

29. 6.MASS SPECTROSCOPY
• It also called as MS
• Here molecules are bombarded with electrons
• Molecules are ionized and broken up into fragments
(m/e)
• By this molecular weight, molecular formula can be
predicted from the spectrum

30. PHYSICAL QUANTITATIVE PARAMETERS
• Ash values
• Extractive values
• Moisture content
• Volatile oil determination

31. ASH VALUES
The residue remaining after incineration is the ash
content of the drug.( inorganic salts of carbonates,
phosphates, silicates of sodium, potassium,
calcium and magnesium) is known as ash content.
Ash value is a criterion to judge the identity OR
purity of the crude drug

32. TYPES OF ASH VALUES
1.Total ash value
2.Acid insoluble ash value
3.Sulphated ash value
4. Water soluble ash value

33. Total ash value:
Useful for detecting low grade products
Useful for detecting exhausted products
Useful for detecting excess of sandy
Useful for detecting earthy matter with drug

34. • Examples
• Aloes – Total ash content 5 %
• Clove - Total ash content 7 %
• Ginger -Total ash content 5 %
• Cardamom - Total ash content 6 %

35. DETERMINATION OF TOTAL ASH VALUE
1. Weigh accurately about 3gms of the powdered drug
in a tared silica crucible
2. Incinerate the powdered drug by gradually increasing
the heat until free from carbon and cool. Keep it in
desiccators
3. Weigh the ash and calculate the % of the total ash
with reference to the air dried sample

36. CHEMICAL EVALUATION
• Qualitative evaluation to detect different classes of
phytochemicals
• Quantitative determination of phytochemicals
• Assay

38. BIOLOGICAL EVALUATION
• Animal activity
• Animal organ
• Tissue activity

39. SIGNIFICANCE:
1.The method is generally used when
standardization is not done satisfactory by
chemical or physical methods
2.When the quantity of the drug /sample are very
less then the drugs are evaluated by biological
methods

40. These methods are performed on living animals,
isolating living organ and tissue, animal preparation,
and micro-organism
( Bioassay)

41. Following method is used as
1.Anti inflammatory activity
2.Analgesic activity
3.Antipyretic activity
4.Anti ulcer activity
5.Antidiabetic activity
6.Anthelmintic activity on earth worms

42. 7. Cardiac activity- on frog and pigeon
8. Microbiological methods- living bacteria, yeast, molds
are used for the assaying vitamins and to determine
the activity of antibiotic drugs

44. MICROSCOPIC EVALUATION
• Qualitative histological evaluation of types and
arrangement of tissues
• Quantitative assessment of stomatal index and
stomatal number , palisade ratio , vein islet ,vein
termination and lycopodium method

45. MICROSCOPIC METHOD
• SIGNIFICANCES
• Used for the evaluation of organized drugs by their
known histological characters
• Helps for the study of constituents by application of
chemical methods to small quantities of drugs in
powdered form or histological sections of the drug
(Microchemistry or Chemo-chemistry)

46. • Methods of microscopic evaluation
• 1.Histology
• 2.Chemomicroscopy
• 3.Powder analysis
• 4.Microscopical linear measurements
• 5.Quantitative microscopy

47. 1.HISTOLOGY
Histological studies are made from very thin sections of
drugs. The characteristics of Cell walls, Cell constituents,
Trichomes, Fibres, Vessels etc., can be studied in details
Eg, Lignified trichomes in Nux vomica
Eg, Warty trichomes in senna

48. Eg, Wavy medullary rays in Cascara
Eg, The powdered clove do not contain sclerides OR
Calcium oxalate crystals , but both of them are
present in powdered clove stalk

49. • 2.Chemomicroscopy OR Microchemistry
• By using some simple tests helps for the detection of
some constituents
• Eg: A drop of phloroglucinol and conc. Hydrochloric acid
give red stain with Lignin
• Mucilage is stained pink with Ruthenium red solution
• Iodine solution stains Starch and Hemicellulose blue
color

50. 3.Powder analysis
It helps in identification and detection of adulterant
Eg. Rhubarb and Ginger are characterized by their non
lignified vessels
Eg. Varieties of Aloes by the presence OR absence of
Crystals of Aloin
Eg. Powder Nux vomica is identified from lignified
trichomes

51. • 4.Microscopic Linear Measurements
• Diameter of starch grains will assist in distingushining
varieties
• Eg. Cassia – 10 microns from Cinnamon- 8 microns
• Eg. Length and width of the phloem fibres
• Eg. Cinchona- 580- 1350 microns lenght

52. • 5.Quantitative microscopy
• It includes
• a) Stomatal Index and Stomatal number
• b) Vein islets number
• c) Palisade ratio

53. • Stomatal Index
• It is the percentage which the number of stomata form to
the total number of epidermal cells is called stomatal
index.
• Stomatal number
• It is average number of stomata per square millimeter of
leaf

54. • B) Vein islets number
• It is defined as number of vein islets present in 1 square
millimeter of leaf surface midway between midrib and
margin
• C) Palisade ratio
• It is average number of palisade cells beneath each
epidermal cell. Palisade ratio can be determined with the
powdered drug.

56. CHEMICAL METHOD
• SIGNIFICANCE:
• 1.Used for the determination of amount of single active
constituent OR the group of related constituents in the
same drug
• 2.The purity of crude drugs is ascertained by quantitative
estimation of active constituents present in them

57. • Types of chemical evaluation
• 1. Gravimetric method
• 2. Volumetric method
• 3. Acid value, Saponification value, Iodine value, Ester
value
• 4. Thin layer chromatography
• 5. Qualitative chemical tests

58. • GRAVIMETRIC METHOD
• Principle:
In this method known amount of the drug is taken , the
active chemical constituents are isolated, dried to a
constant weight and then weight is determined.
Example: Total alkaloid content in solanaceous drugs
Podophyllin in podophyllum root
Balsamic acid in balsam of peru and balsam of tolu

59. • VOLUMETRIC METHOD
• Used for the determination of physico-chemical
characteristics of the fixed oils and fats , includes Acid
value, Saponification value, Iodine value
• Non aqueous titration methods used for the analysis of
organic acids
• Example; Eugenol in clove oil, Carvone in caraway oil and
Dill oil, Ephedrine in Ephedra by non–aqueous titration

60. • THIN LAYER CHROMATOGRAPHY
• Here comparison of retention factor values (Rf)
with standards ascertain qualitative evaluation of
constituents
Rf values –
Example: Eugenol- 0.47
Caravone - 0.46
Borneol - 0.24

61. • QUALITATIVE CHEMICAL ANALYSIS
• By using some simple chemical tests for identifying
specific organic groupings which may be present in
any drug to which its therapeutic activity is
attributed.
• Alkaloids – Dragendroffs Test
• Glycosides/ Sugars – Molischs Test
• Steroids – Lieberman Burchard Test
• Anthraquinones – Borntrager Test

62. • Flavonoids – Shinoda Test
• Tannins – Ferric Chloride Test
• Reducing Sugar – Fehling Solution Test
• Deoxy sugars - Keller- kiliani Test
• Mucilage - Ruthenium red solution
• Proteins and Amino acids - Ninhydrin Test

64. MORPHOLOGICAL EVALUATION
• Qualitative evaluation of colour , odour, and
taste , shape, extra features

65. MORPHOLOGY
SIZE – of plant parts like rhizomes, roots, corms,
bulbs, tubers, fruit, seed, stem etc
SHAPE – of the plant part like napiform,
annulated,
COLOUR – the range of colour like greyish of nux
vomica seeds
EXTERNAL MARKINGS – like furrows, wrinkles,
ridges, annular, outgrowths etc.

66. ODOUR
Aromatic
Balsamic
Camphoraceous
Spicy
Pleasant
Irritating

67. TASTE
Bitter
Sour
Astringent
Pungent
Acid
alkaline

68. SOUND – to see the ripeness of the fruit /
seed etc
FRACTURE
Granular
Splintery
Smooth

69. PLANT PARTS
Bud, Flower, Fruit, Leaf, Root, Seed, Stem
HABIT & HABITAT
Annual, Aquatic, Biennial, Climber, Creeper,
Epiphyte, Habit (Herb, Shrub) Perennial, Tree
etc
PHYLLOTAXY
Alternate, Opposite, Whorled

70. APEX OF LEAF
Acuminate, Acute, Obtuse
MARGIN OF LEAF
Ciliate, Crenate, serrate, entire, undulate
SHAPE OF LEAF
Cordate, Lanceolate, Oblong, Ovate

71. TYPE OF LEAF
Simple, Compound, Pinnate, Palmate
VENATION OF LEAF
Parellel, Reticulate, Unicosate, multicosate
INFLORESCENCE
Cymose, RAcemose
FLOWERS
Epigynous, Hypogynous, Perigynous
FRUITS
Drupe, Berry

72. WHO BIOLOGICAL EVALUATION
• Swelling Index determination
• Foam Index determination
• Haemolytic Index determination

73. SWELLING INDEX DETERMINATION
Definition :
The swelling index is the volume in ml taken up by
the swelling of 1 gm of plant material in water under
specified conditions.
Significances :
Useful in the evaluation of crude drugs with swelling
properties especially gums and mucilage, pectin and
hemicelluloses
Useful for the detection of purity of the crude drug

74. DETERMINATION
1. Transfer 1 gm of the seeds to a 25ml stoppered
cylinder
2. Fill up to the 20ml mark on the cylinder with water.
Agitate gently and occasionally during 24 hours
and allowed to stand
3. Measure the volume occupied by the swollen
seeds .
4. Swelling index – Isapaghula seed should be in
between 10-14

75. FOAM INDEX DETERMINATION
• This test is used to measure the foaming ability of an
aqueous decoction of saponin containing medicinal
plant materials which possesses property to form
persistent foam when an aqueous decoction is shaken

76. DETERMINATION
• Prepare aqueous decoction of about 1gm of coarse
powder material in 100ml of water by boiling for 30
minutes.
• Cool and filter into 100ml volumetric flask and add
sufficient amount of water to make up the volume to
100 ml
• Now prepare 10 stoppered test tubes (height – 16cm
and diameter – 16mm) in series containing 1,2,3 up to
10ml and adjust the volume of the liquid in each test
tube with water to 10 ml

77. DETERMINATION
• Stopper the tubes and shake them in a lengthwise
motion for 15 seconds, 2 frequencies per second.
• Allow to stand for 15 minutes and measure the height
of the foam
• Foaming Index = 1000/ A
• A- Volume of decoction having exact 1cm height.
• Examples – Licorice, Diascorea

78. HAEMOLYTIC INDEX DETERMINATION
• Saponins have ability to cause haemolysis where
haemoglobin diffuses into the surrounding medium
through a change in the erythrocytic membrane and
makes blood a clear solution

79. HAEMOLYTIC INDEX DETERMINATION
• The haemolytic activity of plant materials , or a
preparation containing saponins, is determined by
comparison with that of a reference material.
• A suspension of erythrocytes is mixed with equal
volumes of a serial dilution of the plant material extract.
• The lowest concentration to affect complete
haemolysis is determined after allowing the mixtures to
stand for given period of time.
• A similar test is carried out simultaneously with
saponin.