Digitalis – Source, diagnostic characters, constituents, uses, adulterants and substitutes

Digitalis

Source, diagnostic characters, constituents, uses, adulterants ands ubstitutes

Digitalis

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

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

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

Powder characters

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

Tests

Keller KIliani test (For digitoxose)

1gm Drug + 10 ml 70%
alcohol, Boil

â

Filter, to the
filtrate add 5 ml water, 0.5 ml strong lead acetate solution

â

Shake and separate
the filtrate

â

Clear filtrate
treated with chloroform and evaporated to dryness

â

Extract dissolved in
glacial acetic acid

â

Cooled, 2 drops of
ferric chloride solution is added

â

Content transferred
to test tube with 2 ml conc, sulphuric acid

â

Reddish brown layer
acquiring bluish green colour after standing – Digitoxose

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

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

Adulterants

Verbascum Thapsus – Scrophulariaceae – Candelabra
trichomes

Primrose leaves Primula vulgaris – Primulaceae – uniseriate covering trichomes (8-9 cells)

Comfrey leavesSymphytum officinale – Boraginaceae – Multicellular trichome with hook in top

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

Digitalis lutea – Scrophulariaceae – Straw fox glove

• Sessile, oblanceolate with serrate or dentate margin

• As potent as D. purpurea

• Common substitute for official drug

 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

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

Also, Visit:

B. Pharma Notes | B. Pharma Notes | Study material Bachelor of Pharmacy pdf

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B. Pharma PDF Books

B. Pharma Lab Manual

D. Pharma Lab Manual

B. Pharma 8th Semester Previous Year Question Paper

D. Pharma Notes

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