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ACONITE (Aconitum)
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See also:ACONITE (Aconitum) , a genus of See also:plants belonging to the natural See also:order See also:Ranunculaceae, the See also:buttercup See also:family, commonly known as aconite, monkshood or wolfsbane, and embracing about 6o See also:species, chiefly natives of the mountainous parts of the See also:northern hemisphere. They are distinguished by having one of the five See also:blue or yellow coloured sepals (the posterior one) in the See also:form of a See also:helmet; hence the See also:English name monkshood. Two of the petals placed under the See also:hood of the calyx are sup-ported on See also:long stalks, and have a hollow See also:spur at their See also:apex, containing See also:honey. They are handsome plants, the tall See also:stem being crowned by racemes of showy See also:flowers. Aconitum Napellus, See also:common monkshood, is a doubtful native of See also:Britain, and is of therapeutic and toxicological importance. Its roots have occasionally been mistaken for See also:horse-See also:radish. The aconite has a See also:short underground stem, from which dark-coloured tapering roots descend. The See also:crown or upper portion of the See also:root gives rise to new plants. When put to the See also:lip, the juice of the aconite root produces a feeling of numbness and tingling. The horse-radish root, which belongs to the natural order See also:Cruciferae, is much longer than that of the aconite, and it is not tapering; its See also:colour is yellowish, and the See also:top of the root has the remains of the leaves on it. Many species of aconite are cultivated in gardens, some having blue and others yellow flowers. Aconitum lycoctonum, wolfsbane, is a yellow-flowered species common on the See also:Alps of See also:Switzerland. The roots of Aconitum ferox See also:supply the famous See also:Indian (See also:Nepal) See also:poison called bikh, bish or nabee. It contains considerable quantities of the See also:alkaloid pseudaconitine, which is the most deadly poison known. Aconitum palmatum yields another of the celebrated bikh poisons. The root of Aconitum luridum, of the Himalayas, is said to be as virulent as that of A. ferox or A. Napellus. As See also:garden plants the aconites are very ornamental, See also:hardy perennials. They thrive well in any See also:ordinary garden See also:soil, and will grow beneath the shade of trees. They are easily propagated by divisions of the root or by seeds; See also:great care should be taken not to leave pieces of the root about owing to its very poisonous See also:character. See also:Chemistry.—The active principle of Aconitum Napellus is the alkaloid aconitine, first examined by P. L. Geiger and See also:Hesse (See also:Ann., 1834, 7, p. 267). See also:Alder See also:Wright and A. P. Luff obtained
apoaconitine, aconine and benzoic See also:acid by See also:hydrolysis; while, in 1892, C. See also:Ehrenberg and A. Purftirst (Journ. Prat. Chem., 1892, 45, p• 604) observed acetic acid as a hydrolytic product. This, and allied alkaloids, have formed the subject of many investigations by See also:Wyndham See also:Dunstan and his pupils in See also:England, and by See also: Pseudaconitine, obtained from Aconitum ferox, gives on hydrolysis acetic acid and veratrylpseudaconine, the latter of which suffers further hydrolysis to veratric acid and pseudaconine. Japaconitine, obtained from the See also:Japanese aconites, known locally as " kuza-uzu," hydrolyses to japbenzaconine, which further breaks down to benzoic acid and japaconine. Other related alkaloids are lycaconitine and myoctonine which occur in wolfsbane, Aconitum lycoctonum. The usual test for solutions of aconitine consists in slight acidulation with acetic acid and addition of See also:potassium permanganate, which causes the formation of red crystalline precipitate. In 1905, Dunstan and his collaboraf~ors discovered two new aconite alkaloids, indaconitine in " mohri " (Aconitum chasmanthum, Stapf), and bikhaconitine in " bikh " (Aconitum spicatum) ; he also proposes to classify these alkaloids according to whether they yield benzoic or veratric acid on hydrolysis (Jour. Chem. See also:Soc., 1905, 87, pp. 162o, 165o). From the root of Aconitum Napellus are prepared a liniment and a See also:tincture. The dose of the latter (Brit. Pharmacop.) is of importance as being exceptionally small, for it is not advisable to give more than at most five drops at a See also:time. The See also:official preparation is an ointment which contains one See also:part of the alkaloid in fifty. 
It must be used with extreme care, and in small quantities, and it must not be used at all where cuts or cracks are See also:present in the skin. See also:Pharmacology of Aconite and Aconitine.—Aconite first stimulates and later paralyses the nerves of See also:pain, See also:touch and temperature, if applied to the skin, broken or unbroken, or to a mucous membrane; the initial tingling therefore gives See also:place to a long-continued anaesthetic See also:action. Taken internally aconite acts very notably on the circulation, the respiration and the See also:nervous See also:system. The See also:pulse is slowed, the number of beats per See also:minute being actually reduced, under considerable doses, to See also:forty, or even See also:thirty, per minute. The See also:blood-pressure synchronously falls, and the See also:heart is arrested in diastole. Immediately before See also:arrest the heart may See also:beat much faster than normally, though with extreme irregularity, and in the See also:lower animals the auricles may be observed occasionally to See also:miss a beat, as in poisoning by veratrine and See also:colchicum. The action of aconitine on the circulation is due to an initial stimulation of the cardio-inhibitory centre in the medulla oblongata (at the root of the vagus nerves), and later to a directly toxic See also:influence on the See also:nerve-ganglia and See also:muscular See also:fibres of the heart itself. The fall in blood-pressure is not due to any See also:direct influence on the vessels. The respiration becomes slower owing to a paralytic action on the See also:respiratory centre and, in warm-blooded animals, See also:death is due to this action, the respiration being arrested before the action of the heart. Aconite further depresses the activity of all nerve-terminals, the sensory being affected before the motor. In small doses it therefore tends to relieve pain, if this be present. The activity of the See also:spinal See also:cord is similarly depressed. The See also:pupil is at first contracted, and afterwards dilated. The cerebrum is totally unaffected by aconite, consciousness and the intelligence remaining normal to the last. The antipyretic action which considerable doses of aconite display is not specific, but is the result of its influence on the circulation and respiration and of its slight diaphoretic action. See also:Therapeutics.-The indications for its employment are limited,but definite. It is of undoubted value as a See also:local See also:anodyne in See also:sciatica and See also:neuralgia, especially in ordinary facial or trigeminal neuralgia. The best method of application is by rubbing in a small quantity of the aconitine ointment until numbness is See also:felt, but the costliness of this preparation causes the use of the aconite liniment to be commonly resorted to. This should be painted on the affected part with a See also:camel's See also:hair See also:brush dipped in See also:chloroform, which facilitates the absorption of the alkaloid. Aconite is indicated for See also:internal See also:administration whenever it is desirable to depress the action of the heart in the course of a See also:fever. Formerly used in every fever, and even in the septic states that constantly followed surgical operations in the pre-Listerian See also:epoch, aconite is now employed only in the earliest See also:stage of the less serious fevers, such as acute tonsilitis, See also:bronchitis and, notably, See also:laryngitis. The extreme pain and rapid swelling of the vocal cords—with threatened obstruction to the respiration—that characterize acute laryngitis may often be relieved by the sedative action of this See also:drug upon the circulation. In order to reduce the pulse to its normal See also:rate in these cases, without at the same time lessening the See also:power of the heart, the drug must be given in doses of about two minims of the tincture every See also:half-See also:hour and then every hour until the pulse falls to the normal rate. Thereafter the drug must be discontinued. It is probably never right to give aconite in doses much larger than that named. There is one See also:condition of the heart itself in which aconite is sometimes useful. Whilst absolutely contra-indicated in all cases of valvular disease, it is of value in cases of cardiac hyper-See also:trophy with over-action. But the practitioner must be assured that neither valvular See also:lesion nor degeneration of the myocardium is present. See also:Toxicology.—In a few minutes after the introduction of a poisonous dose of aconite, marked symptoms supervene. The initial signs of poisoning are referable to the alimentary See also:canal. There is a sensation of burning, tingling and numbness in the mouth, and of burning in the See also:abdomen. Death usually supervenes before a numbing effect on the See also:intestine can be observed. After about an hour there is severe vomiting. Much motor weakness and cutaneous sensations similar to those above de-scribed soon follow. The pulse and respiration steadily fail, death occurring from See also:asphyxia. As in See also:strychnine poisoning, the patient is conscious and clear-minded to the last. The only See also:post-mortem signs are those of asphyxia. The treatment is to empty the See also:stomach by See also:tube or by a non-depressant emetic. The physiological antidotes are atropine and digitalin or strophanthin, which should be injected subcutaneously in maximal doses. Alcohol, strychnine and warmth must also be employed. Additional information and CommentsThere are no comments yet for this article.
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