4.digitalis

Source • Dried leaves of Digitalis purpurea Scrophulariaceae • Dried at not more than 60°C & moisture content not more than 5% • Externally used by Welsh “Physicians of Myddfai ” but no name was given • Named by Fuchs • Therapeutical properties were investigated by William Withering

Cultivation • Requires light sandy soil free from weeds with certain amount of Manganese as essential element • It was found in semi shady positions in wild state • Raised from seeds • Seeds are mixed with sand & sown in seed beds in autumn • Seedlings are set out in field in the following April in rows 1mt apart

Collection • In 1st yr plants form rosettes of leaves & 1st harvest is done in Aug • Next yr flowering stem occurs which is cut down to encourage foliage & harvested in Mar / Apr & again in later in the year • Plants with removed flowering stems continues to yield leaves for several years instead of dying . If it was not cut the plant dies • Some farmers collect 1st yr crop in Sept & plough up whole field

Drying • Leaves are collected in dry weather & dried as rapidly as possible at about 60°C • Spread on trays with wire netting bottom , stacked on runners in a well closed , dark drying shed by hot air from a furnace at basement & ventilated above / in a tunnel dryer • Drying takes place for about 4 – 10 days 2nd method • Leaves are put on heated shelves of vacuum drying oven & the process completed in few hours • They were stored in drying rooms until needed

Description • Size • Shape • Color • • • • •

Margin Base Apex Texture Taste

Cultivated ones are larger than wild sources Ovate – Lanceolate Petiolate , Winged Upper Deep green & greyish Lower Pale green & more greyish crenate to serrate or dentate & has water pores Decurrent Subacute Pubescent , Hairy & Papery Bitter

• Side veins leave the midrib at an angle of 45°, curving towards apex & anastamose near the margin

Microscopy (dorsiventral leaf) • Epidermis (u)

Single layered Thick cuticle Anomocytic stomata Covering trichomes Numerous Uniseriate 3-4 cell long Glandular trichomes Few & present over veins Unicellular stalk with uni / bi cellular head • Lower Epidermis More number of stomata & trichomes • Mesophyll Palisade single layered Sometimes undifferentiated Calcium oxalate absent

Midrib • • • • •

Strongly convex Both the epidermis present Below epidermis collenchyma on both the sides Remaining made up of parenchyma V.B Arc shaped More towards ventral surface Surrounded by endodermis containing starch With in endodermis collenchymatous pericycle • Xylem towards the ventral surface • Phloem towards the dorsal surface • Each marginal tooth has a water pore

Constituents • Glycosides • 1st yr leaves collected in Jul / Aug have high content of total glycosides . There after a fall during winter months . Another peak occurs , but not as high as 1st yr , at the time of flowering • Series I Purpurea glycosides A , B , glucogitaloxin • Series II( formed by enzymatic degradation on drying with loss of terminal glucose ) Digitoxin , Gitoxin , Gitaloxin

Aglycones Series A

Series B

Purpurea glycoside A

Purpurea Glucogitaloxin glycoside B

Glucose – (Digitoxose)3 –

Digitoxin

Gitoxin

(Digitoxose)3 –

Gluco Digitalinum odoroside H verum

Series E

Gitaloxin

Sugars at C3

Glucoverodoxin Glucose – Digitalose –

Odoroside H Strospeside Verodoxin

Digitalose –

Uses • Cardiotonic in congestive heart failure • Blocks Na – K – ATP ase pump • Shortens systole

Keller – Kiliani Test • 1gm powder + 70% alcohol 10ml boil & filter • Filtrate + 10ml water + 0.5ml lead acetate shake & filter • Filtrate shaken with 5ml CHCl3 allow to separate • Pipette of CHCl3 & remove solvent by evaporation on porcelain dish • Dissolve residue in 3ml glacial acetic acid containing 2 drops of 5%ferric chloride • Carefully transfer this solution to the surface of 2ml of conc.H2SO4 • Reddish brown layer at the junction of two liquids • Upper layer slowly becomes bluish green & darken upon standing