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49. Siddha system of medicine is based on principles
of:
A. Biguna B. Rigveda
C. Triguna D. Atharveda
50. Unanisystemofmedicineisbasedonprinciples
of:
A. 4 humours B. 5 humours
C. 4 Gunas D. 5 Gunas
51. The traditional Chinese system of medicine is
based on the Chinese cosmology of:
A. Yin and Yang B. Kin and Kang
C. bin and bang D. Yin and Zing
52. Tridosha occurs in:
A. Chinese system of medicine
B. Ayurveda
C. Unani system of medicine
D. Siddha system of medicine
53. Homeopathic system of medicine is based on
doctrine of:
A. Similia similibus curantur
B. Disimilia similibus curantur
C. Dismilia ismilibus curantur
D. None of the above
54. Hypothesis of ayurveda:
A. Composed of 5 basic elements
B. Composed of 3 basic elements
C. Composed of 7 basic elements
D. Composed of 6 basic elements
55. Tridoshas are:
A. Vata, pitta, kapha B. Vata, rasa, rakta
C. Pitta, meda, majja D. Mamsa, rasa, rakta
56. Ayurveda is an:
A. Chinese system of medicine
B. Siddha system of medicine
C. Unani system of medicine
D. Indian system of medicine
57. Hippocratic theory is composed of:
A. 4 humours B. 3 humours
C. 5 humours D. 6 humours
58. Unanisystemofmedicineisbasedon:
A. Hippocratic theory
B. Three basic elemental theory
C. Yin and Yang theory
D. Five basic elemental theory
59. Yin and Yang means:
A. Day & night B. Pitta & Kapha
C. Rasa & Rakta D. Vata & pitta
60. Pythagoriantheoryiscomposedof:
A. 5 proximate qualities
B. 4 proximate qualities
C. 3 proximate qualities
D. 2 proximate qualities
61. Homeopathic system of medicine was developed
by:
A. Aristotle
B. Galen
C. Samuel Hahnemann
D. Hippocrates
62. The Organon of medicine book is used in:
A. Unani system of medicine
B. Siddha system of medicine
C. Homeopathy system of medicine
D. Chinese system of medicine
63. This system of medicine was identified with
Dravidian culture:
A. Siddha system of medicine
B. Unani system of medicine
C. Homeopathy system of medicine
D. Indian system of medicine
64. The literature of Siddha system is in:
A. Telugu B. Tulu
C. Tamil D. Sanskrit
ANSWER KEY
1. A 2. 3. A 4. D 5. B 6. A 7. B 8. D 9. C 10. 11. A 12. D 13. A 14. A
15. B 16. C 17. D 18. 19. C 20. B 21. D 22. C 23. C 24. D 25. B 26. 27. A 28. A
29. B 30. B 31. B 32. A 33. A 34. 35. A 36. A III B I C II 37. B 38. A III B I C II D IV
39. A IV B I C II D III 40. A I B II C III 41. B 42. B 43. C 44. A 45. A 46. A 47. B 48. D
49. C 50. A 51. A 52. B 53. A 54. A 55. A 56. D 57. A 58. A 59. A 60. A 61. A 62. C
63. A 64. C
Section 2 Pharmacognosy
159
4. Techniques in Microscopy
Reagents with properties and Uses
S. No. Reagents Properties Uses
1 Chloral hydrate TS Refractive index (nD 20) of 1.44–1.48. It is the best reagent for rendering
calcium oxalate clearly evident and is
particularly useful for small crystals.
2 Lactochloral TS Lactochloral TS has a similar use to
chloral hydrate TS,
It is usually applied to sections that are
difficult to clarify. It may be used cold.
3 Lactophenol TS Lactophenol TS may be used cold or
with heating. It has a refractive index
(nD 20) of 1.44
4 Sodium hypochlorite TS The bleached sections give a negative
reaction to lignin.
5 Xylene R and light
petroleum R
Solvents for fats and oils It is used to remove fats and oils from
It is useful for the preparation of fungi,
pollen grains, most non-oily powders, and
parasites such as mites and nematode
worms.
Sodium hypochlorite TS is used for
bleaching deeply coloured sections.
oily powders or sections.
Techniques of Histochemical Detection
S.No. Particulars Method
1 Cellulose cell walls Add 1–2 drops of iodinated zinc chloride TS and allow to stand for a few minutes;
alternatively, add 1 drop of iodine (0.1 mol/l) VS, allow to stand for 1 minute, remove
excess reagent with a strip of filter-paper and add 1 drop of sulfuric acid (~1160 g/l)
TS; cellulose cell walls are stained blue to blue-violet. On the addition of 1–2 drops
of cuoxam TS, the cellulose cell walls will swell and gradually dissolve.
2 Lignified cell walls Moisten the powder or section on a slide with a small volume of phloroglucinol TS
and allow to stand for about 2 minutes or until almost dry. Add 1 drop of hydrochloric
acid (~420 g/l) TS and apply a cover-glass; lignified cell walls are stained pink to
cherry red.
3 Suberized or cuticular
cell walls
4 Aleurone grains Add a few drops of iodine/ethanol TS; the aleurone grains will turn yellowish brown
5 Calcium carbonate Crystals or deposits of calcium carbonate dissolve slowly with effervescence when
6 Calcium oxalate Crystals of calcium oxalate are insoluble in acetic acid (~ 60g/l) TS but dissolve
7 Fats, fatty oils, volatile
oils and resins
8 Hydroxyanthraquinones Add 1 drop of potassium hydroxide (~55 g/l) TS; cells containing
Section 2 Pharmacognosy
9 Inulin Add 1 drop each of 1-naphthol TS and sulfuric acid (~1760 g/l) TS; spherical
160
Add 1–2 drops of sudan red TS and allow to stand for a few minutes or warm gently;
suberized or cuticular cell walls are stained orange-red or red.
to brown. Then add a few drops of ethanolic trinitrophenol TS; the grains will turn
yellow. Add about 1 ml of mercuric nitrate TS and allow to dissolve; the colour of
the solution turns brick red. If the specimen is oily, render it fat-free by immersing
and washing it in an appropriate solvent before carrying out the test.
acetic acid (~60 g/l) TS or hydrochloric acid (~70 g/l) TS is added.
in hydrochloric acid (~70 g/l) TS without effervescence (if applied by irrigation the
acid should be more concentrated); they also dissolve in sulfuric acid (~350 g/l) TS,
but needle-shaped crystals of calcium sulphate separate on standing after about
10 minutes. In polarized light, calcium oxalate crystals are birefringent. Calcium
oxalate is best viewed after the sample has been clarified (e.g. with chloral
hydrate TS).
Add 1–2 drops of sudan red TS and allow to stand for a few minutes or heat
gently, if necessary. The fatty substances are stained orange-red to red. Irrigate
the preparation with ethanol (~750 g/l) TS and heat gently; the volatile oils and
resins dissolve in the solvent, while fats and fatty oils (except castor oil and croton
oil) remain intact.
1,8-dihydroxyanthraquinones are stained red.
aggregations of crystals of inulin turn brownish red and dissolve.
Contd...
S.No. Particulars Method
10 Mucilage Add 1 drop of Chinese ink TS to the dry sample; the mucilage shows up as
transparent, spherically dilated fragments on a black background. Alternatively,
add 1 drop of thionine TS to the dry sample, allow to stand for about 15 minutes,
then wash with ethanol (~188 g/l) TS; the mucilage turns violet-red (cellulose and
lignified cell walls are stained blue and bluish violet respectively).
11 Starch Add a small volume of iodine (0.02 mol/l) VS; a blue or reddish blue colour is
produced. Alternatively, add a small volume of glycerol/ethanol TS and examine
under a microscope with polarized light; birefringence is observed giving a maltese
cross effect with the arms of the cross intersecting at the hilum.
12 Tannin Add 1 drop of ferric chloride (50 g/l) TS; it turns bluish black or greenish black.
5. Introduction of Phytoconstituents
CARBOHYDRATES
Carbohydratesarethemostabundantclassoforganic
compoundsfoundinlivingorganisms.
Theyoriginate as products of photosynthesis, an
endothermicreductive condensation of carbon
dioxide requiring light energy and the pigment
chlorophyll.
Carbohydratesare dened as Polyhydroxyaldehyde
orPolyhydroxyketone, orsubstance that gives these
compounds on hydrolysis.
Classification of Carbohydrates
Category Example Site Structures
Monosaccharides
(made of 1 sugar
molecule)
Glucose,
Galactose,
fructose
Fruit
Fruit, nectar
Milk
Disaccharide
(made up of 2
monosaccharides
joined together)
Maltose=
α-glucose +
α-glucose
Sucrose= glucose
+ fructose
Lactose= glucose
+ Galactose
Germinating
seeds
Pholem tissue,
fruit
Milk
Contd...
Section 2 Pharmacognosy
161
Category Example Site Structures
Polysaccharide
(made up
of many
monosaccharides
joined together)
Starch= polymer
of glucose
Glycogen=
Polymer of
α-glucose
Cellulose=
Polymer of
β-glucose
Chitin = Polymer
of glucosamine
Chloroplast
stroma
Muscle cells
Plant cell wall
Exoskeleton of
arthropods
CHEMICAL TEST OF CARBOHYDRATES
Test for starch:Tothesolutionofcarbohydratesadd2–3
dropsofiodine,Blue/blackprecipitate(ppt)forms.
Test of reducing sugar:Tothesolutionofcarbohydrates
addequalquantityofBenedict’sreagentMix.Heatto70°C
(do not boil because this would split a disaccharide, e.g.
sucroseintoreducingsugars (glucose andfructose)and
giveafalsepositivetest).Solutionturnsfrombluetopale
greentoyellowtoorangetobrickred ppt of copper (I)
oxide,e.g.glucose,fructoseandmaltose.
Test of non-reducing sugar: To 2 cm
3
1 cm
dilute HCl Boil. Cool and neutralise with excess
NaOH.Repeattestforreducingsugar.
3
test solution add
Functions of carbohydrates
1. Immediate respiratory substrates, e.g. glucose
2. Energy stores, e.g. glycogen in mammals starch in plants
3. Structural components, e.g. cellulose in plant cell walls
chitin in arthropod exoskeleton
4. Pentose sugars—ribose and deoxyribose are components
ofRNAandDNArespectively.
5. Metabolites, i.e. intermediates in biochemical
pathways
6. Cell-to-cell attachment molecules, e.g. combined
withproteinstoformglycoproteinsorlipidstoform
glycolipids on plasma membrane
7. Transport, e.g. sucrose in plant phloem tissue
Section 2 Pharmacognosy
162
Mild laxative,
tonic and
digestive
effects.
cure
3
Blue or green
fluorescence
gives deep
in UV light.
5% FeCl
dysentery,
diarrhoea,
hepatitis,
tuberculosis,
blue black
colour
Lead acetate
solution it
dyspepsia
and good for
heart and
brain.
gives white
ppt
Nutritive, as
a demulcents
in cough,
cold and
Reduction
of Fehling’s
solution
Test for
constipation,
also as a
laxative,
antiseptic
and vehicle
artificial invert
sugar: honey
adulterated
with artificial
invert sugar
for ayurvedic
preparations.
due to
presence of
furfural give
cherry red
colour
Contd...
Alkaloids, coumarin and steroid
Gray-green,
Aromatic.
Mucilaginous,
Consist of
Epicarp,
Mesocarp
and
bark, leaves
Habitat Part Used Characters Chemical Constituents Chemical Test Uses
Native to India Fruit root-
Source
Aegle
marmelos
Rutaceae
Endocarp
Glucose (30-40%) and fructose (40-50%).
sucrose, dextrin, formic acid, volatile
oil and pollen grains in small amount
together with vitamins, proteins and
amino acids
brown liquid
Weight per
ml is 1.35 to
1.36.
Soluble
in water,
insoluble in
alcohol and
other organic
solvents.
Optically
active with
Honeycomb Yellowish-
West indies,
California,
Africa
Apis mellifera
and Apis
dorsata
Apidae
rotation
between +0.6
and 0.3
Name Synonyms Biological
Bael Wood apple,
Bengal
Quince
Mel, purified
honey
Honey Madhu,
Section 2 Pharmacognosy
163
Gum is
used in
confectionery
emulsifier for
10% tannic
acid it
gives white
precipitate.
oil and water
emulsions,
used as a
waterproofing
agent in liquid
With water
it forms
colourless
mucilage of
much greater
explosive,
and to
stabilize
paraffin wax
emulsions.
viscosity than
that made
with same
proportion
acacia
Widely
used as a
treatment for
constipation.
Iodine
solution gives
crimson to
brown colour.
It is mainly
used for
preparation
of nutrient
with
Ruthenium
red gives
pink colour.
media in
bacteriological
preparations.
with Fehling’s
soltion (het)
give red
preipitate.
used
medicinally
as demulcent
With lead
acetate it
produces no
and as a
means of
suspending
precipitate.
Acacia gum
is insoluble
oils, resin,
etc, in
aqueous
fluids.
in alcohol,
saturated
solution of
borax forms
Contd...
with a strong
solution of
gum a clear,
translucent jelly
polysaccharide, galactomannan
calcium and magnesium salt of a
complex polysaccharide which contain
L-arabinose, D-galactose, D-mannose,
D xylose and D- glucuronic acid. It also
contains oxidase.
inferior gum
is yellow to
brown in
colour
Gum exudate Colourless
Indigenous
to India and
Habitat Part Used Characters Chemical Constituents Chemical Test Uses
Ceylon
Wallich family
latifolia
Combretaceae
Anogeissus
Source
Agarose and Agaropectin
Characteristic
Gum exudate White,
large scale in
Japan, Korea,
South Africa,
USA, Spain,
Mexico and
Gelidium
amansii,
family
Gelidaceae
New Zealand.
Gum Arabic
is unique
among the
natural
Gummy
exudates
from stem
and branches
Nigeria and
Senegambia
Acacia
senegal,
family
Leguminosae
hydrocolloids
because of
its extremely
high solubility
in water.
Ghati gum
Section 2 Pharmacognosy
164
Name Synonyms Biological
GHATUGUM
Bakla
Vegetable
Gelatin,
Japanese
Agar Agar-agar,
or Chinese
Gelatin
Gum acacia,
Gum arabic
Acacia
Demulcent,
in making
emulsions
10% aqueous
ferric chloride
solution
deep yellow
precipitate is
obtained.
5% caustic
potash gives
Portion soluble in water Polyarabinan-
trigalaetangeddic acid. insoluble part is
called bassorin
Good
intestinal
cleanser and
stool softner,
canary yellow
colour
Seeds on
slide with
water show
the zone of
30% mucilage, xylose, arabinose,
galaecturonic acid, Rhanose, galactose,
albumin, tannin and acetylcholine. The
seed pulp contains 14.7% lilonic acid and
Popular
fibers and
used to treat
constipation.
mucilage.
when treated
with water
forms jelly
like mass on
5% stable oil.
keeping.
Mucilage
gives pink
colour with
ruthenium
red under
microscope.
Thickener,
water binder,
emulsion
stabilizer and
gelling agent.
Internally it
is used as
astringent,
nutritive,
demulcent,
protective
and
absorbent
Add Iodine-KI
reagent to a
solution.
A blue-black
colour results
if starch is
present
Starch consists of two types of
molecules, amylose (normally 20-30%)
and amylopectin (normally 70-80%). Both
consist of polymers of α-D-glucose units
Habitat Part Used Characters Chemical Constituents Chemical Test Uses
Source
White or pale
yellowish
white flakes
Gummy
exudation
Asia Minor,
Persia and
Kurdistan
Astragalus
gummifer,
Family
Leguminosae
Gum
Tragacanth
convex and
concave
surface,
convex
Seeds, Husk Seeds have
Mediterranean
region and
commercially
grown in north
western India
forsk,
Plantago
ovata
Family
Plantaginaceae
Isapgul
Indian
psyllium
surface have
central glossy
reddish
brown
elongated
spots
whereas
concave
surface
is deeply
groved with
hilum
becomes
soluble in
USA, India,
China and
tuberosum
water when
heated
Japan
(Solanaceae),
Oryza sativa
(Gramineae),
Zea mays
(Gramineae),
Triticum
astivum
(Gramineae)
Name Synonyms Biological
Tragacanth Gum Dragon
Isapgol
Starch Amylum Solanum
Section 2 Pharmacognosy
165
MULTIPLE CHOICE QUESTIONS
1. Select the composition of Molisch’s reagent:
A. Alpha napthol + sulphuric acid
B. Beta napthol + sulphuric acid
C. Naphthylamine + sulphuric acid
D. Phenol + sulphuric acid
2. Selectthechemicaltestusedforidenticationof
carbohydrates:
A. Ninhydrin B. Molisch
C. Borntrager D. Baljet
3. Select the Main chemical constituent of Algin:
A. Tragacanthin B. Bassorin
C. Alginic acid D. Alginic ester
4. Select the Main chemical constituent honey:
A. Glucose B. Fructose
C. Maltose D. Invert sugar
5. Useofpectininthepharmaceuticalindustries
A. Adsorbent B. Demulcent
C. Emulsifying agent D. Suspending agent
6. Select the method to obtain liquid glucose:
A. Partial hydrolysis of glucose
B. Partial hydrolysis of starch
C. Complete hydrolysis of starch
D. Complete hydrolysis of glucose
7. Choose biological source for Indian gum:
A. Cyamopsis tetragonoglobules
B. Astragalus gammifer
C. Acacia Arabica
D. Acacia Senegal
8. When Indian gum is treated with ruthenium red’
it shows:
A. Pink colour B. Red colour
C. Blue D. No colour change
9. When Indian gum is treated with hydrogen
peroxide and benzidine in alcohol; is shows blue
colour due to:
A. Hydrolyase enzyme B. Oxidase enzyme
C. Reductase enzyme D. Invertase enzyme
10. Select the common adulterant for Indian gum
A. Acacia Senegal gum
B. Gum from Astragalus gummifer
C. Gum ghatti from anogeissus latifolia
D. Guar gum
11. Select the synonym for Guar gum:
A. Jaguar gum B. Acacia
C. Gum acacia D. Gum Arabica
12. When guar gum is treated with about 2% solution
of lead acetate; it shows:
Section 2 Pharmacognosy
166
A. Pink colour B. Blue colour
C. Yellow colour D. No colour change
13. Articialinvertsugarisanadulterantforhoney
and it is detected by the test:
A. Tollen’s B. Ninhydrine
C. Baljet test D. Fiehe’s test
14. The water soluble portion of tragacanth is known
as:
A. Tragacanthin B. Bassorin
C. Galctouronic acid D. D-galctopyranose
15. Pectinisusedinthetreatmentof:
A. Ulcer B. Hypertension
C. Angina D. Diarrhoea
16. Biological source for Isapgol:
A. Plantago ovata B. Aegle marmelos
C. Giladinium amansii D. Condrus cripsus
17. Which test is used for the purity of Isapgol?
A. Barfoed test B. Millon’s test
C. Molisch test D. Swelling factor
18. When Isapgol is treated with rhuthenium red, it
shows colour:
A. Blue B. Yellow
C. Pink C. Green
19. Isapgol seeds are adulterated with:
A. Plantago purshii B. Plantago lanciolata
C. Plantago aristala D. Plantago pysllium
20. Agar is used as:
A. Binder B. Disintigrant
C. Emulsifying agent D. Preservative
21. Amylum is the synonym for:
A. Tragacanth B. Starch
C. Inulin D. Locust bean
22. Rice starch is of size:
A. 2–12 micron B. 14–17 micron
C. 17–20 micron D. 20–25 micron
23. Wheat starch is of size:
A. 0.1 to 1 micron B. 2 to 3 micron
C. 3 to 5 micron D. 5 to 50 micron
24. The size of potato starch varies from:
A. 30 to 100 micron B. 100 to 130 micron
C. 130 to 10 micron D. 160 to 180 micron
25. Starch contains amylase and amylopectin in the
proportion:
A. 1:2 B. 1:1
C. 1:3 D. 2:1
26. Thetest,whichis not usedforidenticationof
carbohydrates:
A. Molisch test
B. Osazone formation test
C. Ninhydrin test
D. Resorcinol test
27. Kellerkilianitestisusedforidenticationof:
A. Fructose B. Maltose
C. Deoxy sugar D. Glucose
28. The synonym of lactose is:
A. Milk sugar B. Butter sugar
C. Crystalline sugar D. Pure sugar
C. Psyllium iii) Plantago ovata
D. Isapgol iv) Plantago psyllium
31 Name Biological source
A. Honey i) Oryza sativa
B. Starch ii) Citrus limonis
C. Pectin iii) Apis species
D. Gum karaya iv) Sterculia urens
CHOOSE THE CORRECT PAIRS
29. Name Biological source
A. Carageennan i) Acacia arabica
B. Acacia ii) Chondrus crispus
C. Agar iii) Gelidium amansii
D. Gum ghatti iv) Anogeissus latifolia
30. Carbohydrates Biological source
A. Tragacanth i) Cyamopsis
tetragonolobus
B. Guar gum ii) Astragulus gummifer
32. Starch Size
A. Rice i) 2 to 110 um
B. Potato ii) 2 to 45 um
C. Wheat iii) 2 to 10 um
D. Maize iv) 10 to 30 um
33. Starch Source
A. Wheat i) Zea mays
B. Maize ii) Oryza sativum
C. Rice iii) Triticum sativum
D. Potato iv) Solanum tuberosu
ANSWER KEY
1. A 2. B 3. C 4. D 5. A 6. B 7. C 8. D 9. B 10. C 11. A 12. D 13. D 14. A
15. D 16. A 17. D 18. C 19. B 20. C 21. A 22. A 23. D 24. A 25. A 26. C 27. C 28. A
29. a) ii b) i c) iii d) iv
30. a) ii b) i. c) iv d) iii
31. a) iii b) i. c) ii d) iv
32. a) iii b) i. c) ii d) iv
33. a) iii b) i. c) ii d) iv
6. Glycosides
Glycosidesare the natural organic compounds, from
plants or animal sources which on enzymatic or acid
hydrolysisgiveoneormoresugarmoietiesalongwith
non sugar moieties along with non sugar moieties joined
by a special linkage called glycosidal linkage.
Chemically the glycosides are considered as acetals in
whichthe hydroxyl group of the sugar iscondensed
withahydroxylgroupofthesugariscondensedwith
ahydroxylgroupofthenonsugarcomponentandthe
secondary hydroxyl is condensing with in the sugar
moleculeitselftoformanoxideringsoglycosidesare
also called sugar ether.
Glycosides can be hydrolyzed by enzyme, acid, alkali or
sometimes only with moisture. The enzymes hydrolysed
α-glycosidesareinvertaseandmaltasewhilemyrosin,
linarase, amygdalase, cellobiase and gentianase
hydrolysed β glycosides. Stereochemically, α and β
stereoisomerareassigned.Insimpleform,theglycosides
withthesetwoisoerscanbesynthesizedfromunionof
methyl alcohol and glucose.
Properties
Glycosides are colourless, crystalline or amorphous solid
substances.Flavonesglycosidesareyellowcolouredand
anthracene glycosides are red or orange coloured.
They are soluble in water and alcohol but insoluble in
etherandchloroform.Glycosidesareopticallyactiveand
usuallytheyarelaevorotatorymeansl-form.
Glycosidesare substances of profound physiological
action or animal tissue and are many a times poisnous
forhumanbeings.
Theyare generally the products of special metabolic
processandtheirconcentrationinvariousmorphological
partsalso varies considerablyaccording to ageand
ecologicalfactors of the plant. Thosewhich are most
signicanttherapeuticactionarecardiacglycosides.
Section 2 Pharmacognosy
167
Classification of Glycosides with Examples
Glycosides Drugs
Cardiac or sterol Digitoxin, gitoxin, digoxin from digitalis
Anthraquinone or anthracene Sennosides from senna, cascarosides from cascara, barbolin from aloe.
Saponin glycosides Glycyrrhizin in glycyrrhiza, diosgenin from discorea.
Cyanogenetic or cyanophoric glycosides Amydalin—bitter almond
Prussian—wild cherry bark
Isothiocyanate glycosides Sinigrin—black mustard
Sinalbin—white mustard
Flavanol glycosides Rutin—Ruta, Hesperidin-orange, kaempferol-senna
Alcohol glycosides Salicin—salix
Aldehyde glycosides Salinigrin—salix
Lactone or coumarin Skimmin—staranise, aersculin-harsechest nut bean
Miscellanous Quassium—quassia, picrotoxin-anamista
Stas-otto Method:
1)Thefreshdrymaterialiscoarselypowderedandthen
enzymesareactivated.
2)The extraction is carried out by percolation with mixture
ofmethanolandwaterduetoitssolubilitypattern.
3)The percolate is again treated with lead acetate to
precipitate chlorophyll and tannins and marc is
discarded.
4)Again ltrate andresidue is obtained by ltration of
samplethisltrateistreatedwithH2Sgasto remove
excessofleadacetatesasleadsulphide.
5)Finallyltratethesolutionandevaporateltratetoget
glycosidal residue.
Isolation method for glycosidal drug:
Therearemainlythreetypesofmethodsareusedforit:
1)Bydifferentsolubilitymethod
2)Fractional crystallization
3)By chromatography
By different solubility method:
In this method glycosidal extract is treated with many
solventlike mixture of water and methanol and thus
glycosides are separate out.
Fractional crystallization:-Inthismethodcrystalofdrug
ispreparedbyisolationmethodandbycrystalformation
is separated out.
By chromatography: - In chromatography preparative
typeofTLCisformedinwhichthedifferentcolourwriting
studyisperformed.
Identification Test for Glycosidal Drugs
For normal glycosides
a. Xanthohydroltest:Thedrugis0.125%ofxanthohydrol
in glacial acetic acid and 1% HCl and heated red colour
isobserved.
b. Antimony trichloride test: Cardinolides are treated with
antimony trichloride and trichloroacetic acid blue to
violetcolourisobtained.
c. Libermantest for steroidalglycosides: Steroidal
Section 2 Pharmacognosy
glycosides is treated with CCl4, acetic anhydride and
168
conc. H2SO4violetbluecolourisobtained.
d. Tollens test: Glycosides solution in pyridine is treated
withsilverpaperthesolutionliberatessilver.Thesilver
causesmirroronwalloftesttube.
e. Legal test: Glycosides are treatedwith pyridine (for
dissolution),1dropof2%sodiumnitroprussideand1
dropof20%NaOHdeepredcolourisobserved.
Appilications
1)Cardiacstimulants(Digitalis)
2)Purgative-laxative(Aloe,rhubarb,seena,cascara)
3)Bitter tonics (Picrorrhiza)
4)Expectorants (Wild Cheery)
5)Steriodal drug synthesis (dioscorea)
Cardiac glycosides
Manyoftheplantsknowntocontaincardiacorcardiotonic
glycosideshave long been used as arrow poisons (e.g.
Strophanthus) or as heart drugs (e.g. Digitalis). They are
used to strengthen a weakened heart and allow it to
functionmore efciently, though the dosage must be
controlledvery carefully since the therapeutic dose is
so close to the toxic dose. In plants, cardiac glycosides
areconnedtotheAngiosperms,butarefoundinboth
monocotyledons and dicotyledons.
Thetherapeuticactionofcardioactiveglycosidesdepends
onthe structure of the aglycone,and on thetype and
numberof sugar units attached.Twotypes of aglycone
arerecognized, cardenolides, e.g. digitoxigenin from
Digitalis purpurea and bufadienolides, e.g. hellebrigenin
fromHelleborus niger.
The cardenolides are more common, and the plant
familiesthe Apocynaceae (e.g. Strophanthus), Liliaceae
(e.g. Convallaria), and Scrophulariaceae (e.g. Digitalis)
yieldmedicinal agents. The rarer bufadienolidesare
foundinsomemembersoftheLiliaceae(e.g.Urginea) and
Ranunculaceae (e.g. Helleborus).
Biosynthesis: Formed through mevalonate and
deoxyxylulose pathway
i) For cardiac glycosides
a. Raymand’sTest:Inthistestsmallamountofglycosides
isdissolve in 1 ml of 50% ethanol then0.1 ml of1%
solutionofdinitrobenzeneinethanolisaddedwith2–3