3. Digitalis is a biennial herb
grows wild in European
countries.
For medicinal purposes, the
plant is cultivated in
Holland, England, France,
Germany & North America.
In India it is cultivated in
Kashmir region.
4. Digitus (Latin)- Finger
Purpurea – refers to the purple
colour of the flowers.
5. Digitalis consists of dried leaves of Digitalis purpurea
containing not less than 0.3% of total cardenolides
calculated as Digitoxin.
After collection, leaves are dried immediately at a
temperature not exceeding 60 degree & stored in a
moisture proof container, the drug is required to contain
not more than 5% of moisture.
6. General apperance: Usually broken
& crumpled
Type: Simple
Colour: Dark Greyish-Green
Size: 10-40cm long & 4-20cm wide
Base: Tapering, decurrent(winged
petiole)
Margin: Crenate or Serrate, also
Dentate
Apex: Obtuse or Rounded
7. Venation:Pinnate venation,
prominent on the lower surface
& close network of veinlets
Upper surface: Dark green &
minutely hairy
Lower surface: Greyish green,
very pubescent
Shape: Ovate-lanceolate to
broadly ovate
Odour: Characteristic
Taste: Bitter
8. Digitalis mainly contain Cardiac glycosides
i.e,Cardenolides (C-23)
Saponin glycosides:Gitonin, Digitonin
Digitalis contains 0.2-0.45% mixture of both primary
& secondary cardiac glycosides
(Enzymatic hydrolysis)
Primary glycoside Secondary glycoside
(Acid Hydrolysis)
Secondary glycoside Aglycone
Digitalis also contains several other glycosides
such as Odoroside H, Glucogitaloxin, Gitaloxin,
Verodoxin and Glucoverodoxin.
9. Primary Glycosides Secondary Glycosides Aglycone
Purpurea Digitoxin Digitoxigenin
glycoside A (EH) +Glucose (AH) +3Digitoxose
Purpurea Gitoxin Gitoxigenin
glycoside B (EH) +Glucose (AH) +3Digitoxose
Glucogitaloxin Gitaloxin Gitaloxigenin
(EH) +Glucose (AH) +3Digitoxose
EH - Enzymatic Hydrolysis Enzyme:Digipuridase
AH - Acid Hydrolysis
The primary glycosides are less absorbed & less stable
than secondary glycosides
10.
11. Digitalis increases excitability of Cardiac
muscles and produces more powerful
contractions.
It is effective in Congestive cardiac failure
to increase cardiac output and to relieve
venous congestion.
Hence it is described as a Cardiotonic.
The improvement of circulation through
kidney results in diuresis and loss of edema.
12. Keller-Kiliani’s Test:
Boil 1gm of drug with 70% of alcohol for 2-3min. Filter, to the filtrate
add 10ml of water+0.5ml of strong lead acetate solution. Shake &
filter. Filtrate is shaken with chloroform & allow to separate.
Chloroform layer is seperated and evaporated gently in porcelin dish.
Dissolve the cooled residue in 3ml of glacial acetic acid containing 2
drops of 5% Fecl3. Carefully transfer this solution to 2ml of Con.H2SO4
A reddish brown layer forms
at the junction of two liquids, & the upper layer slowly becomes bluish
green darkening with standing.
13. Balget Test:
Glycosidal extract+ Sodium picrate
Yellow to orange colour
Legals Test:
The extract is dissolved in pyridine
+sodium nitro prusside soln.
to make alkaline Pink to Red
Keddes Test:
Glycoside extract+2% 3,5 dinitro benzoic acid in
methanol+ KOH soln. Blue or violet
colour that fades out(Cardenolide aglycone
present)
14. Digitalis lanata
The leaves of Digitalis lanata
have 3-4 times greater activity
than Digitalis purpurea.
The leaves of Digitalis lanata
used as commercial source of
the most widely used cardio
active glycoside Digoxin.
15. Wolly fox glove leaf , Austrial Digitalis.
SOURCE
These are the dried leaves of Digitalis
lanata, belonging to family Scrophulariacece,
& contain 1%-1.4%
of a mixture of
cardiac glycosides.
16. Leaves are sessile, linear lanceolate.
Size:
25-30cm long &
4-5cm wide
Margin:
Entire
Apex :
Acuminate
17. Lanatosides A, B, C & E. lanatosides
resembling those of Digitalis purpurea
but are acetylated at the Digitoxose
moiety adjacent to terminal glucose.
The greater activity of Digitalis lanata is
due to Digoxin.
(On hydrolysis)
Digoxin Digoxigenin,
contain a hydroxy (OH) group in the 12th
position.
18.
19. Mullein Leaves
Comfrey Leaves
Primrose Leaves
Other species of Digitalis containing
Cardiac glycosides
Digitalis scubalpina, Digitalis dubina,
Digitalis grandiflora, Digitalis ferruginea,
Digitalis mertonensis,,etc
20. Digitalis purpurea
Epidermis: Wavy anticlinal walls.
Stomata: Ranunculaceous or anomocytic.
CoveringTrichomes: Multicelluar & finely
warty with blunt tips. Certain cells of
covering trichomes are collapsed.
Glandular Trichomes: Rare, unicellular &
multicellular stalk having unicellular or
bicellular head.
Note: Calcium oxalate crystals are absent.
21.
22. Epidermis: Irregular beaded walls
Stomata: Anomocytic or Ranunculaceous.
Trichomes: very rare
Note: Calcium Oxalate crystals are absent. If
covering trichomes are present they are
long(10-14 celled) & glandular trichomes with
unicellular stalk & bicellular head or
multicellular stalk with unicellular head.