CUCURBITACEÆ.
FRUCTUS ECBALLII.
Fructus Elaterii; Elaterium Fruit, Squirting Cucumber, Wild Cucumber; F. Concombre purgatif ou sauvage; G. Springgurke.
Botanical Origin—Ecballium[1121] Elaterium A. Richard (Momordica Elaterium L.), a coarse, hispid, fleshy, decumbent plant without tendrils, having a thick white perennial root. It is common throughout the Mediterranean region, extending eastward as far as Southern Russia and Persia, and westward to Portugal. It succeeds well in Central Europe, and is cultivated to a small extent for medicinal use at Mitcham and Hitchin in England.
History—Theophrastus mentions the plant under notice by the name of Σίκυος ἄγριος. It is also particularly noticed by Dioscorides, who explicitly describes the singular process for making elaterium (ἐλατήριον), which was almost exactly like that followed at the present day.
The Wild or Squirting Cucumber was well known and cultivated in gardens in England as early as the middle of the 16th century.[1122]
Description—The fruit is ovoid-oblong, nodding, about 1½ inch long, hispid from numerous short fleshy prickles terminating in white elongated points. It is attached by a long scabrous peduncle, is fleshy and green while young, becoming slightly yellowish when mature; it is 3-celled and contains numerous oblong seeds lodged in a very bitter succulent pulp. The fruit when ripe separates suddenly from the stalk, and at the same moment the seeds and juice are forcibly expelled from the aperture left by the detached peduncle. This interesting phenomenon[1123] is due to the process of exosmosis, by which the juice of the outer part of the fruit gradually passes through the strong contractile tissue which lines the central cavity, until the pressure becomes so great that the cell gives way at its weakest point. This point is that at which the peduncle is articulated with the fruit; and it is the sudden and powerful contraction of the elastic tissue when relieved from pressure that occasions the violent expulsion of the contents of the central cavity.
For the preparation of the officinal elaterium, the fruit has to be employed while still somewhat immature, for the simple reason that it would be impossible to gather it so as to retain its all-important juice if left till quite ripe. When it is sliced longitudinally as in making elaterium, some of the juice is expelled by virtue of the endosmotic action already described, as can easily be seen on examining the contracted lining of the sliced fruit.
Pereira observes[1124] that if the juice of a fruit is received on a plate of glass, it is seen to be nearly colourless and transparent. In a few minutes however, by exposure to the air, it becomes slightly turbid, and small white coagula are formed in it. By slow evaporation, minute rhomboidal crystals make their appearance: these are elaterin.
Hot, dry weather favours the development of the active principle of the drug.[1125]
Microscopic Structure—The middle layer of the fruit is built up of large somewhat thick-walled cells, traversed by a few fibro-vascular bundles. The former abound in small starch grains, and also contain granules of albuminous matter.
Chemical Composition—The experiments of Clutterbuck (1819) proved that the active properties of the elaterium plant reside chiefly, though not exclusively, in the juice that surrounds the seeds; and it is to this juice and to the medicinal product which it yields, that the attention of chemists has been hitherto directed.
The juice obtained by lightly pressing the sliced fruits is at first greenish and slightly turbid. After having been set aside a few hours, it yields a deposit, which has to be collected on calico, rapidly drained with gentle pressure between layers of bibulous paper and porous bricks, and dried in a warm place. The substance thus obtained is the Elaterium of pharmacy.[1126] The method recommended by Clutterbuck[1127] involves no pressing. The juice of the sliced fruit is saved, and the pulp, scooped out by the thumb of the operator, is thrown on a sieve and slightly washed with pure water. From these liquors, elaterium is deposited.
Elaterium occurs in irregular cake-like fragments, light, friable, and opaque; when new, of a bright pale green, becoming by age greyish and exhibiting minute crystals on the surface. It has a herby tea-like odour and a very bitter taste. The produce is extremely small: 240 lb. of fruit gathered at Mitcham, 1Oth August 1868, yielded 4⅝ ounces of elaterium = 0·123 per cent.
Elaterium consists, according to Pereira, of Elaterin, to which the activity of the drug is due, contaminated with green colouring matter, cellular tissue, and starch, together with a little of the residue of the bitter liquor from which these substances were deposited. Yet, in our opinion, this description is not applicable to the best varieties of elaterium. We have examined elaterium carefully prepared in the laboratory of Messrs. Allen and Hanburys, London, and a fine specimen imported from Malta. Both are devoid of starch, as well as of cellular tissue, but were seen to be largely made up of crystals. The first sample contained 12 per cent. of water, and yielded after drying, 8·4 per cent. of ash.
The most interesting principle of elaterium is Elaterin, C₂₀H₂₈O₅, discovered about the year 1831 by Morries, and independently by Hennell. The best method of obtaining it, according to our experience, is to exhaust elaterium with chloroform. From this solution, a white crystalline deposit of elaterin is immediately separated by addition of ether. It should be washed with a little ether, and recrystallized from chloroform. We have thus obtained 33·6 per cent. of pure elaterin from the above-mentioned elaterium of London, and 27·6 per cent. from that of Malta. Elaterin crystallizes in hexagonal scales or prisms; it has an extremely bitter, somewhat acrid taste. It is readily soluble in boiling alcohol, amylic alcohol, bisulphide of carbon, or chloroform. Its alcoholic solutions are neutral and are not precipitated by tannin, nor by any metallic solution. It is but very little coloured by cold concentrated sulphuric acid.
Elaterin is the drastic principle of Ecballium; if to its boiling alcoholic solution, solid caustic potash is added, the liquid thus obtained is stated by Buchheim (1872) to be no longer precipitable by water. The elaterin is then in fact converted into an acid body, which may be separated by supersaturating the solution with a mineral acid. The principle thus obtained has been found by Buchheim to be devoid of drastic power.
The fresh juice of the fruits was found by Köhler (1869) to contain 95 per cent. of water, 3 to 3·5 of organic and 1 to 1·6 of inorganic constituents. The same chemist observed that the percentage of elaterin gradually diminished as the season advanced, until in the month of September he was unable to obtain any of it whatever.
Walz (1859) found in the juice of the fruits and herb of Ecballium, as well as in that of Cucumis Prophetarum L., a second crystallizable bitter principle, Prophetin, and the amorphous substances Ecballin or Elateric Acid, Hydro-elaterin, and Elateride, all of which require further examination.[1128] Prophetin is a glucoside,—not so the other principles. The four together constitute, according to Walz, 8·7 per cent. of elaterium, which moreover contains about the same percentage of pectic matter.
Uses—Squirting cucumbers are only employed for making elaterium, which is a very powerful hydragogue cathartic.[1129] Elaterin is not employed in medicine, but seeing how much elaterium is liable to vary from climate or season, it might probably be introduced into use with advantage.
FRUCTUS COLOCYNTHIDIS.
Colocynth, Coloquintida, Bitter Apple; F. Coloquinte; G. Coloquinthe.
Botanical Origin—Citrullus Colocynthis Schrader (Cucumis Colocynthis L.)—The colocynth gourd is a slender scabrous plant with a perennial root, native of warm and dry regions in the Old World, over which it has an extensive area.
Commencing eastward, it occurs in abundance in the arid districts of the Punjab and Sind, in sandy places on the Coromandel coast, in Ceylon, Persia as far north as the Caspian, in Arabia (Aden), Syria, and in some of the Greek islands. It is found in immense quantities in Upper Egypt and Nubia, spreading itself over sand hillocks of the desert after each rainy season. It further extends throughout North Africa to Morocco and Senegambia, in the Cape de Verd Islands, and on maritime sands in the south-east of Spain and Portugal. Finally, it is said to have been collected in Japan.
History—Colocynth was familiar to the Greek and Roman, as well as to the Arabian physicians; it also occurs in Susruta (“Indravārunī”); and if we may judge by the mention of it in an Anglo-Saxon herbal of the 11th century,[1130] was not then unknown in Britain. The drug was collected in Spain at an early period, as is evident from an Arabic calendar of a.d. 961.[1131]
The plant has been long cultivated in Cyprus, and its fruit is mentioned in the 14th century as one of the more important products of the island.[1132] Tragus (1552) figured the plant, and stated that the fruit is imported from Alexandria.
Description—The colocynth plant bears a gourd of the size and shape of an orange, having a smooth, marbled-green surface. It is sometimes imported simply dried, in which case it is of a brown colour; but far more usually it is found in the market peeled with a knife and dried. It then forms light, pithy, nearly white balls, which consist of the dried internal pulp of the fruit with the seeds imbedded in it. This pulp is nearly inodorous, but has an intensely bitter taste, perceptible by reason of its dust when the drug is slightly handled. The balls are generally more or less broken; when dried too slowly they have a light brown colour.
The seeds are disposed in vertical rows on 3 thick parietal placentæ, which project to the centre of the fruit, then divide and turn back, forming two branches directed towards one another. Owing to this structure, the fruit easily breaks up vertically into 3 wedges in each of which are lodged 2 rows of dark brown seeds. The seeds, of which a fruit contains from 200 to 300, are of flattened ovoid form, ³/₁₀ of an inch long by ²/₁₀ broad, not bordered. The testa which is hard and thick, having its surface minutely granulated, is marked on each side of its more pointed end by two furrows directed towards the hilum. The seed, as in other Cucurbitaceæ, is exalbuminous, and has thick oily cotyledons, enclosing an embryo with short straight radicle directed towards the hilum.
Colocynth fruits are mostly supplied by wholesale druggists, broken up and having the seeds removed, the drug in such case being called Colocynth Pulp or Pith.
Microscopic Structure—The pulp is made up of large thin-walled parenchymatous cells, their outer layer consisting of rows of smaller cells more densely packed. The tissue is irregularly traversed by fibro-vascular bundles, and also exhibits numerous large intercellular spaces. The cells contain but an insignificant amount of minute granules, to which neither iodine nor a persalt of iron imparts any coloration. The tissue is not much swollen by water, although one part of the pulp easily retains from 10 to 12 parts of water like a sponge.
Chemical Composition—The bitter principle has been isolated in 1847 by Hübschmann.[1133] He observed that alcohol removes from the fruit a large amount of resin. By submitting this solution to distillation, the bitter principle remains partly in the aqueous liquid, partly in the resin, from which the “Colocynthin” is to be extracted by boiling water. The whole solution was then concentrated and mixed with carbonate of potassium, when a thickish viscid liquid separated. Hübschmann dried it and redissolved it in a mixture of 1 part of strong alcohol and 8 parts of ether. After treatment with charcoal, the solvents were distilled and the remaining bitter principle removed by means of water. This on evaporating afforded 2 per cent. of the pulp of a yellow extremely bitter powder, readily soluble in water or alcohol, not in pure ether. Colocynthin is precipitated from its aqueous solution by carbonate of potassium. Colocynthin was further extracted by Lebourdais (1848) by evaporating the aqueous infusion of the fruit with charcoal, and exhausting the dried powder with boiling alcohol.
Again, another method was followed by Walz (1858). He treated alcoholic extract of colocynth with water, and mixed the solution firstly with neutral acetate of lead, and subsequently with basic acetate of lead. From the filtered liquid the lead was separated by means of sulphuretted hydrogen, and then tannic acid added to it. The latter caused the colocynthin to be precipitated; the precipitate washed and dried was decomposed by oxide of lead, and finally the colocynthin was dissolved out by ether.
Walz thus obtained about ¼ per cent. of a yellowish mass or tufts, which he considered as possessing crystalline structure and to which he gave the name Colocynthin. He assigns to it the formula C₅₆H₈₄O₂₃, which in our opinion requires further investigation. Colocynthin is a violent purgative; it is decomposed according to Walz by boiling dilute hydrochloric acid, and then yields Colocyntheïn, C₄₄H₆₄O₁₃, and grape sugar. The same chemist termed Colocynthitin that part of the alcoholic extract of colocynth which is soluble in ether but not in water. Purified with boiling alcohol, colocynthitin forms a tasteless crystalline powder.
The pulp perfectly freed from seeds and dried at 100° C., afforded us 11 per cent. of ash; the seeds alone yield only 2·7 per cent. They have, even when crushed, but a faint bitter taste, and contain 17 per cent. of fat oil.
The fresh leaves of the plant if rubbed emit a very unpleasant smell.
Commerce—The drug is imported from Mogador, Spain and Syria.
Uses—In the form of an extract made with weak alcohol, and combined with aloes and scammony, colocynth is much employed as a purgative. The seeds, roasted or boiled, are the miserable food of some of the poorest tribes of the Sahara.[1134]
The people of the Berber upon the Nile make a curious application for the tar they obtain from the fruit. The latter is heated in an earthen vessel with a hole in it; the tar drips through to another vessel and is fit for smearing leather water-bags. The bad smell of the tar (and of the leaves) prevents the camels from cutting open the water-bags.[1135]
Substitutes—Cucumis trigonus Roxb. (C. Pseudo-colocynthis Royle), a plant of the plains of Northern India, with spherical or elongated, sometimes obscurely trigonous, bitter fruits, prostate rooting stems, and deeply divided leaves, resembles the colocynth gourd and has been mistaken for it. Another species named by Royle C. Hardwickii, and known to the natives of India as Hill Colocynth, has oval oblong bitter fruits, but leaves entirely unlike those of the Citrullus Colocynthis.