Glycosides
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Content
Glycosides
✓ Source, diagnostic characters, constituents, uses, adulterants and
substitutes of Digitalis
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Objectives
• At the end of this lecture, student will be able to
– Discuss the source, diagnostic characters, constituents,
uses, adulterants and substitutes of Digitalis
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Digitalis
Synonym
Digitalis leaf, foxglove leaf
Source
Dried leaves of Digitalis purpurea, dried at temp below 60oC,
immediately after collection, should not contain more than 5 %
moisture
Family
Scrophulariaceae
Geographical source
England, Europe, US, India
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Digitalis
Macroscopy
Colour – Dark greyish green
Odour – Slight
Tatse – Bitter
Size – 10-40 cm in length, 4-20 cm wide
Shape- ovate- Lanceolate to broadly ovate
Margin – Irregularly crenate or serrate or occasionally dentate margin
Venation – Pinnate
Texture – Pubescent
Veinlets prominent in the lower surface
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Digitalis
Microscopy
✓ Dorsiventral
✓ Stomata – Anamocytic
✓ Trichomes
❖ Covering – uniseriate, multicellular (3-5 cells), blunt apex,
(collapsed cell covering trichomes)
❖ Glandular – Unicellular stalk, uni or bicellular head, seen in
veins
✓ Free from calcium oxalate and scelerenchyma
✓ Collenchyma – upper epidermis, lower epidermis, pericycle
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Digitalis
Microscopy
Digitalis
Powder characters
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Digitalis
Constituents
✓ Cardiac glycosides – cardenolides
✓ Pupurea glycosides A & B, Glucogitaloxin – primary glycosides
✓ Purpurea glycoside A – Digitoxin + glucose – digitoxigenin + 3 –
digitoxose
✓ Purpurea glycoside B – Gitoxin + glucose – Gitoxigenin + 3 –
digitoxose
Other glycosides
✓ Odoroside H, Gitaloxin, verodoxin, glucoveradoxin
✓ Saponin glycosides
✓ Digitonin, gitonin
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Digitalis
Tests
Keller KIliani test (For digitoxose)
1 gm Drug + 10 ml 70% alcohol, Boil
Filter, to the filtrate add 5 ml water, 0.5 ml strong lead acetate solution
Shake and separate the filtrate
Clear filtrate treated with chloroform and evaporated to dryness
Extract dissolved in glacial acetic acid
Cooled, 2 drops of ferric chloride solution is added
Content transferred to test tube with 2 ml conc, sulphuric acid
Reddish brown layer acquiring bluish green colour after standing – Digitoxose
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Digitalis
Tests
Legal test
Extract dissolved I pyridine, sodium nitro prussiade solution is added,
made alkaline – pink or red colour
Baljet test
Section of digitalis- sodium picrate – yellow to orange
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Digitalis
Assay
✓ Bioassay – IP suggests pigeon or guinea pig
Use
✓ CHF – blocks the Na-K ATPase pump, hence intracellular Na level
increase- leads to increase in Ca ions – protein action is enhanced
(actin, myosin) – forceful contraction of myocardium
✓ Slows ventricular rate in atrial fibrillation, atrial flutter,
supraventricular tachycardia and premature extra systoles
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Digitalis
Adulterants
✓ Verbascum Thapsus – Scrophulariaceae – Candelabra trichomes
✓ Primrose leaves – Primula vulgaris – Primulaceae – uniseriate
covering trichomes (8-9 cells)
✓ Comfrey leaves – Symphytum officinale – Boraginaceae –
Multicellular trichome with hook in top
V. thapsus Pw.w vwu.lDgualroiMs i x .c o m S1. 3officinale
Digitalis
Allied drugs
Digitalis lanata – Scrophulariaceae – Wooly fox glove
Constituents
✓ Primary glycosides – Lanotoside A, B, C, D, E (glycone- digitoxose is
acetylated)
Use
✓ Commercial source for digoxin, lanatoside C,
Lanatoside A and mixture of lanatosides
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Digitalis
Allied drugs
Digitalis lutea – Scrophulariaceae – Straw fox glove
✓ Sessile, oblanceolate with serrate or dentate margin
✓ As potent as D. purpurea
✓ Common substitute for official drug
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Digitalis
Allied drugs
Digitalis thapsi –Scrophulariaceae – Spanish fox glove
✓ Small leaves, yellowish green, lanceolate with crenate
✓ Covering trichome absent
✓ Calcium oxalate present
Other species
✓ D. subalpine
✓ D. dubia
✓ D. grandiflora
✓ D. ferruginea
✓ D. mertonensis www.DuloMix.com 16
Summary
➢ Digitalis – Digitalis purpurea, dried at temp below 60oC, immediately
after collection, should not contain more than 5 % moisture –
Cardenolides – Purpurea glycoside A & B – Kellerkiliani test – cardio
tonic
➢ Allied drugs include D. lanata, D. lutea, D. thapsi etc
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Thank You
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