This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Ergot is the sclerotium of Claviceps purpurea, Tulasne, (N.O. Pyreno-mycetes) originating in the ovary of the rye, Secale cereale, Linne (N.O. Gramineoe).
In the spring or early summer the spores of Claviceps purpurea are carried by the wind on to the flowers of various Graminaceous plants, in the case under consideration on to those of the rye. Here they germinate and produce colourless hyphae, which envelop, with the exception of the apex, the very young ovary, and penetrate the outer part of the pericarp, covering it with a soft white felted mass, which gradually takes the place of the ovary, and is known as the sphacelia. During this period a saccharine secretion, 'honeydew,' is produced by the hyphae, and at the same time numbers of conidia are formed, thus contributing to the further dissemination of the fungus by means of the insects attracted to the honeydew, a small weevil which feeds on the saccharine secretion being especially active. After the felted mass has reached its full development, the sclerotium is gradually produced at its base by the hyphae forming a dense compact mass instead of a loose felt. The sclerotium grows and finally projects from the ear of rye (which has by this time ripened), bearing on its apex the remains of the felt.
In this compact form the fungus is able to resist the damp and cold of the autumn and winter. In the spring it produces small stalk-like projections (stromata, fig. 116, b) each of which is terminated by a globular head in which numberless spores (ascospores) are developed, and these, carried by the wind on to the flowers of the rye, complete the cycle.
Fig. 115. - Ear of Rye bearing two fully developed ergots. Natural size. (Luer-ssen).
Ergot is collected chiefly in Spain, Russia, Germany, and Austria. It is sometimes picked grain by grain by hand, or more usually separated from the rye after it has been thrashed by a machine specially designed for that purpose. Its exclusion from the grain is, in countries in which rye-bread forms the staple food of the people (as in Russia), a matter of the utmost importance, as the continued consumption of bread containing ergot has led to widespread disease (ergotism). The epidemics known as 'ignis sacer' and ' St. Anthony's Fire' were traced in 1747 to ergot. The chief centres for the collection of the drug in Russia are Tomsk, Omsk, and Viatka.
Fig. 116. - A, Ergot of Rye (Planchon and Collin). B, Ergot of Rye germinating (Luerssen).
The grains of ergot are usually about 1.5 to 3.5 cm. in length, and of a very dark violet or nearly black colour. They are slender and curved, tapering towards both ends and rounded or obscurely triangular in section; to one extremity a small whitish appendage (remains of the sphacelia) is often attached. They are longitudinally furrowed, especially on the concave side, and often bear as well numerous small transverse fissures. Ergot breaks easily with a very short fracture, and is whitish or pinkish white within, but does not exhibit any definite structure when examined with a lens. It has a characteristic disagreeable odour and an unpleasant mawkish taste.
It should be thoroughly dried and kept in air-tight vessels to protect it from deterioration by damp and by the attack of insect pests.
The most important constituent of ergot is ergotoxine (Barger and Dale, 1906, hydroergotinine, Kraft, 1906), C35H41N506, an amorphous alkaloid yielding crystalline salts. This substance contracts the pregnant uterus, raises the blood pressure and darkens the cock'scomb, all characteristic effects of ergot, but does not produce convulsions. It is readily convertible into its lactone ergotinine (Kraft) which is crystalline but inactive. It is soluble in alcohol but insoluble in water.
A second active constituent is tyrosamine (Barger, 1909) also called ergotamine. It is parahydroxyphenylethylamine, a crystalline base contained in putrid meat (Barger and Walpole, 1909) and derivable from tyrosine, a constituent of muscular tissue by loss of C02. This base is soluble in water and like ergotoxine causes contraction of the uterus and rise in blood pressure. It is more stable than ergotoxine and is the chief active constituent in the official preparations of ergot.
A third active constituent is histamine (βֳ-aminoethylglyoxaline) or β-iminazolylethylamine; also called ergotidine) a based erivable from histidine, also a constituent of muscle, by loss of CO, just as tyrosamine is derivable from tyrosine. Histamine is exceedingly potent, soluble in water, and causes contraction of the non-pregnant uterus but lowers the blood pressure.
To these three bases the activity of ergot is mainly to be ascribed. Other but much weaker constituents are isoamylamine (derivable from leucine) and agmatine (derivable from arginine).
Ergot also contains ergothioneine a base containing sulphur and of doubtful activity; fixed oil (about 30 per cent.); scleroxanthin and sclerocrystallin (crystalline yellow substances); sclererythrin (reddish violet colouring matter); ergotinic acid, an ill-defined organic acid which has no action on the uterus; sphacelinic acid, a resinous acid which contracts the blood vessels and also produces convulsions; a glucoside, clavicepsin.
Cornutine (Keller), secalintoxin and sphacelotoxin (Jacobj) are mixtures of ergotoxine with ergotinine. Chrysotoxin and ergochrysin (Jacobj) are also impure substances. Ergotinine (Tanret), sclerocrystallin (Podwissotzky), secalin (Jacobj), and picrosclerotin (Dragen-dorff) are impure ergotinine.
The two chief commercial varieties are Spanish and Russian, the former being distinguished by its larger size.
Ergot is also collected in Germany, Austria, in the Canary Islands (occasionally), and in this country (rarely).
Ergots will grow on many Graminaceous plants, e.g. Triticum sativum, Lamark, Festuca elatior, Linne, F. arundinacea, Vill. Prosp., Lolium perenne, Linne, L. multiflorum, Lamark, Poa annua, Linne. Ergots grown on Festuca and on Lolium appear to be specially active.
As there is no known method of determining ergotoxine no chemical assay is at present available. It is, however, possible to obtain an insight into the relative activity of preparations of ergot by injecting them into fowls and observing the extent of gangrene produced in the combs and wattles. The determination of the inactive ergotinine which is frequently Carried out is, of course, valueless.
The chief action of ergot is the stimulation of plain muscle, especially of the uterus and of the arterioles in peripheral parts of the body; it is employed to excite or increase uterine contraction and to control uterine haemorrhage.