Nux Vomica

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Chapter: Pharmacognosy and Phytochemistry : Drugs Containing Alkaloids

Nux vomica consists of the dried ripe seeds of Strychnos nux vomica Linn, belonging to family Loganiaceae; containing not less than 1.2% strychnine.






Semen strychni, Nux vomica Seed, Poison Nut, Semen strychnos, Quaker Buttons, Bachelor’s buttons, Dog buttons, Vomit nut, Crow fig.


Biological Source


Nux vomica consists of the dried ripe seeds of Strychnos nux vomica Linn, belonging to family Loganiaceae; containing not less than 1.2% strychnine.


Geographical Source


It is mainly found in South India, Malabar Coast, Kerala, Bengal, Eastern Ghats, North Australia and Ceylon.


Cultivation and Collection


The plant is a small tree around 12 m in height. Ripe and mature fruits are collected in the month of November to February. The fruits are 3–5 cm in diameter and are sub-spherical yellowish brown orange like berries. The epicarp is leathery and the pulp is bitter whitish and mucilaginous in which two to five seeds are embedded. The epicarp is separated and the seeds are removed and washed to remove pulp. They are dried on mats in the sun and graded according to size and exported.




A medium-sized tree with a short, crooked, thick trunk, the wood is white hard; close grained, durable and the root very bitter. Branches irregular, covered with a smooth ash-coloured bark; young shoots deep green, shiny. Leaves opposite, short stalked, oval, shiny, smooth on both sides, about 4 inches long and 3 inches broad. Flowers small, greenish-white, funnel shape, in small terminal cymes, blooming in the cold season and having a disagreeable smell. Fruit, about the size of a large apple with a smooth hard rind or shell which when ripe is a lovely orange colour, rilled with a soft white jelly-like pulp containing five seeds covered with a soft woolly like substance, white and horny internally. Seeds have the shape of flattened disks densely covered with closely appressed satiny hairs, size is 10–30 mm in diameter 3–5 mm thick, radiating from the centre of the flattened sides and giving to the seeds a characteristic sheen; they are very hard, with a dark grey horny endosperm in which the small embryo is embedded; no odour but a very bitter taste.


                               Strychnos nux vomica



Epidermis consists of thick-waved, bent and twisted lignified covering trichomes. The base of the trichome is large thick walled with slit like pits. The upper part of the trichome is nearly at right angle to the base and has wavy walls. Endosperm consists of thick walled isodiametric cells consisting of hemicellulose which swells with water and contains plasmodesma. Aleurone grains and fixed oil are present in endosperm and embryo.


           Transverse section of Nux vomica seed

Chemical Constituents


Nux vomica contains the alkaloids, Strychnine (1.25%) and Brucine (1.5%), also traces of strychnicine, and a glucoside Loganin, about 3% fatty matter, caffeotannic acid and a trace of copper. It contains about 2.5–3.5% bitter indole alkaloids. Strychnine is therapeutically active and toxic alkaloid and is located in central portion of endosperm. Brucine is chemically dimethoxystrychnine and is less toxic and has very little physiological action. It is intensely bitter and is used as a standard for determining the bitter value, of many bitter drugs. Brucine is more in the outer part. Vomicine and pseudostrychnine are minor alkaloids.


The seeds also contain chlorogenic acid or caffeotannic acid. Alkaloids are combined with chlorogenic acid or caffeotannic acid. Loganin, a glucoside is also present. Cell walls of endosperm of nux vomica are thick walled and contain reserve material hemicellulose consisting of mannan and galactan which on hydrolysis yield mannose and galactose. Fatty matter is 3% aleurone grains and a trace of copper is present in the endosperm of the seed. The pulp of the fruit contains about 5% of loganin together with the alkaloid strychnicine.


Chemical Tests

1. Strychnine Test: To a section of endosperm add ammonium vanadate and sulphuric acid. Strychnine in the middle portion of endosperm is stained purple.


2. Potassium dichromate test: Strychnine gives violet colour with potassium dichromate and conc. sulphuric acid.


3. Brucine Test: To a thick section add concentrated nitric acid. Outer part of endosperm is stained yellow to orange because of brucine.


4. Hemicellulose Test: To a thick section add iodine and sulphuric acid. The cell walls are stained blue.




The properties of nux vomica are substantially those of the alkaloid Strychnine. In the mouth it acts as a bitter, increasing appetite; it stimulates peristalsis, in chronic constipation due to atony of the bowel it is often combined with cascara and other laxatives with good effects. Strychnine, the chief alkaloid constituent of the seeds, also acts as a bitter, increasing the flow of gastric juice; it is rapidly absorbed as it reaches the intestines, after which it exerts its characteristic effects upon the CNS, the movements of respiration are deepened and quickened and the heart slowed through excitation of the vagal centre. Strychnine has a stimulant action on spinal cord and reflex movements are better. It is considered as nervine and sex tonic. The senses of smell, touch, hearing and vision are rendered more acute, it improves the pulse and raises blood pressure and is of great value as a tonic to the circulatory system in cardiac failure. In toxic doses strychnine causes violent tetanus like convulsions and death takes place due to asphyxia and respiratory failure.


Brucine closely resembles strychnine in its action, but is slightly less poisonous; it paralyses the peripheral motor nerves. It is said that the convulsive action characteristic of strychnine is absent in brucine almost entirely. It is used in pruritis and as a local anodyne in inflammations of the external ear. Nux vomica is also known as vomiting nut but it has no vomiting properties. However Strychnos potatorum has emetic action.


Marketed Products


It is one of the ingredients of the preparation known as Neo Tablets (Charak Pharma Pvt. Ltd.).


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