Synonyms:
Strychni Semina, Crow Fig.
Botanical source:
Nux-vomica consists of the dried seeds of Strychnos nux-vomica Linn., a small tree of the family Loganiaceae.
Geographical source:
The plant grows wild in India, West Indies, and Cameroon and sporadically in Chittagong Hill Tracts of Bangladesh.
Macroscopical characters:
The seed is disc-shaped with a silky surface densely covered with lignified hairs and a ridge around its circumference, IO to 30 mm in diameter and 4 to 6 mm thick, ash-gray or greenish gray in colour. The seed coat is tough with radially arranged hairs and a raised hilum with the radial ridge running to the micropyle on the margin. Endosperm is large, horny and bluish to brown in colour. Embryo is small, heart-shaped, with two thin, leaf-like cotyledons and a pronounced radicle. Odour none but taste is very bitter.
Microscopical characters:
The seed coat is very thick, the epidermal cells of which are extended to form long stiff trichomes, 400 to 1000 um long and about 25 um is diameter. The walls are very thick, lignified and marked with oblique pits near the base. The trichomes are bent a short distance from the base and have about 10 longitudinal ribs. The endosperm is situated’ below the epidermis. The upper cells are elongated, thick-walled and constitute a palisade-like layer. The rest of the endosperm is composed of thick-walled cellulosic parenchyma. The cell walls are composed mainly of hemicellulose. Abundant fixed oil and aleurone grains occur in the endosperm cells.
Fig. 43: Nux-vomica. A, external surface; B, section parallel to the flat faces; C, section at right angles to the flat faces; D, t.s. of outer part; E, t.s. of limbs of trichomes; F, bases of trichomes in surface view; G. cells of endosperm, cav, central cavity; cot, cotyledon; end, endosperm; ep, epidermis; hi, hilum; m, micropyle; r, ridge; rad, radicle; t, testa. (Adopted from Wallis).
Nux Vomica Seeds Chemical Constituents:
The seed drug Nux-vomica contains the indole alkaloids, strychnine (about 1.24 %) and brucine (about 1.5 %). It also contains caffeotannic acid, a glycoside, loganin, and a fixed oil.
Uses of Nux Vomica Seeds:
It is used as a bitter tonic and stomachic and is given in constipation. It increases blood pressure. Thus it is also useful in certain cases of heart failure. In large doses, it causes convulsions and thus is used in pharmacological research.
Substitutes and Adulterants:
Dried seeds of other Strychnos species, particularly S. potatorum and S. nux-blanda have been frequently used to substitute and adulterate official Nux-vomica.