Datura Herb

DATURA HERB

Biological Source

Datura herb consists of the dried leaves and flowering tops of Datura metel Linn and Datura metel var. fastuosa belonging to family Solanaceae.

Geographical Source

It is found in India, England and other tropical and sub-tropical countries.

Characteristics

Datura metel is also an Indian plant and resembles D. fastuosa; it differs in that the leaves are heart-shaped, almost entire and downy, and the flowers always white.

D. metel var. fastuosa is known in commerce as black datura. The leaves are ovate and more or less angular, the flowers being mostly purplish, sometimes white. Corolla is double or triple. Outer corolla has five teeth and inner Corolla has six to ten teeth.

                               Datura metel

Microscopy

Transverse section shows a bifacial structure. The following characters were observed in the lamina and the midrib region. In the lamina it has the upper epidermis which is single layer, rectangular cells covered with cuticle. Both covering and glandular trichomes are present. The covering trichomes are uni-seriate, multicellular, warty and with blunt apex. The glandular trichomes have one stalk consisting of one cell and multicellular head. The mesophyll has spongy parenchyma and palisade parenchyma in it. Palisade cells are radially elongated, single layer and compactly arranged. Spongy parenchyma are several layers, loosely arranged consisting of micro-sphenoidal crystals and vascular strands. In the midrib, strips of collenchyma appear below the upper and above the lower epidermis followed by the cortical parenchymatous cells containing calcium oxalate. The lower epidermis is similar to that of the upper one but has more number of trichomes and stomata when compared with upper epidermis.

                              T.S. (schematic) diagram of datura leaf

                         Transverse section of datura leaf 

Chemical Constituents

Datura herb contains up to 0.5% of total alkaloids, among which hyoscine (scopolamine) is the main alkaloid, while l-hyoscyamine (scopoline) and atropine are present in very less quantities.

                                       scopolamine

Chemical Tests

1.     Vitali-Morin test: The tropane alkaloid is treated with fuming nitric acid, followed by evaporation to dryness and addition of methanolic potassium hydroxide solution to an acetone solution of nitrated residue. Violet colouration takes place due to tropane derivative.

2.     On addition of silver nitrate solution to solution of hyoscine hydrobromide, yellowish white precipitate is formed, which is insoluble in nitric acid, but soluble in dilute ammonia.

Uses

In Ayurveda black datura is considered more efficacious or more toxic. D. metel is used in the manufacture of hyoscine or scopolamine. It exhibits parasympatholytic with anticholinergic and CNS depressant effects. The drug is used in cerebral excitement, asthma and in cough. The Rajpoot mothers are said to smear their breasts with the juice of the D. metel leaves, to poison their newly born female infants.

Other species

D. arborea, a South American species (the Tree Datura), growing freely in Chile, contains about 0.44% alkaloid, nearly all hyoscine. A tincture of the flowers is used to induce clairvoyance. D. quercifolia, of Mexico, contains 0.4% in the leaves and 0.28% of alkaloids in the seeds, about half hyoscyamine and half hyoscine. Datura innoxia is found throughout India. It is a perennial herb with a thick fleshy hairy stem. Leaves are thick and pubescent. Corolla is single, white, 10 toothed and calyx inflated. Fruit is a capsule with prominent spines. Leaves contain both hyoscine and hyoscyamine. Datura tatula, Purple Stramonium owes its activity to the same alkaloids as D. Stramonium, and its leaves are also much used in the form of cigarettes as a remedy for spasmodic asthma. D. ferox, Chinese Datura, is used in homoeopathy.

Marketed Products

It is one of the ingredients of the preparations known as Jatifaladi Bati, Jatyadi tail (Baidyanath) and J.P. Massaj oil, Pain kill oil, J.P. Grace oil (Jamuna Pharma).