Visnaga

VISNAGA

Synonyms

Bishop’s flower, Greater Ammi, Khaizaran, Khellakraut, Khillah, Pick Tooth, Toothpick weed, Viznaga.

Biological Source

These are the fruits of Ammi visnaga Linn., belonging to family Umbelliferae.

Geographical Source

It is mainly found in Europe, West Asia, Egypt, West Africa.

Cultivation and Collection

It is an Annual/Biennial growing to 0.75 m by 0.4 m. The plant prefers a well-drained soil in a sunny position, succeeding in ordinary garden soil. Tolerates a pH in the range of 6.8–8.3. The seeds are sown in prepared beds on a well drained loamy soil in the month of August. When the plants attain a height of 6–7 cm they are transplanted to open fields. The crop is cut in March–April when the fruits are ripe. The dried plants are thrashed on the floor and the fruits are collected and winnowed.

Characteristics

Fruit, cremocarp, usually separated into its two mericarps, rarely entire, with a part of the pedicel attached. Mericarp, small, ovoid, about 2 mm long and 1 mm broad; crowned with a disc-like nectary, the stylopod; brownish to greenish-brown with a violet tinge (Distinction from Ammi majus); externally, glabrous, marked with five distinct, pale brown-ish, rather broad primary ridges and four inconspicuous dark secondary ridges; internally, the mericarp shows a pericarp with six vittae, four in the dorsal and two in the commis-sural side, a large oily orthospermous endosperm and a small apical embryo. Carpophore, single, no split; passing at the apex in to the raphe of each mericarp. Odour, slightly aromatic; taste, aromatic, bitter and slightly pungent.

Microscopy

The mericarp is an almost regular pentagon and the seeds are orthospermous. There are five vascular strands and four vittae; on the outer side of each vittae a group of radiating club shaped cells and these cause a slight elevation of the surface over each vitta, thus forming the secondary ridges. It contains a large lacuna on the outer side of each vascular strand in the primary ridges.

Chemical Constituents

The drug contains furanocoumarin compounds. The chief constituents are khellin and visnagin, which are γ-benzopyrone derivatives. Khellol and khellol glucoside are also present. In addition it contains pyranocoumarin esters visnadin, samidin and dihydrosamidin. Fixed oil and proteins are also present.

Chemical Test

The drug when treated with strong mineral acid shows lemon yellow colour while in Ammi majus dirty green brown colour is seen.

Uses

Visnaga is an effective muscle relaxant and has been used for centuries to alleviate the excruciating pain of kidney stones. Khellin is used in treatment of asthma. The seeds are diuretic, antiasthmatic and lithontripic. The seeds have a strongly antispasmodic action on the smaller bronchial muscles; they also dilate the bronchial, urinary and blood vessels without affecting blood pressure.

Marketed Products

It is one of the ingredients of the preparations known as Lukoskin oral drops (Aimil Pharmaceuticals).