ACONITE 297 



too early. The taste is at first slight, but is followed by a persistent 

 sensation of tingling and numbness in the mouth. Although the 

 daughter roots are usually more active than the parent root, the 

 British Pharmacopoeia admits the use of either, uniformity being 

 ensured by the assay. 



The student should observe 



(a) The elongated conical shape, 



(b) The starchy interior and stellate cambium, 



(c) The characteristic tingling taste. 



Constituents. Aconite root contains three closely allied alkaloids, 

 viz. aconitine, picraconitine (benzoylaconine), and aconine. 



In addition to these alkaloids the root contains starch and aconitic 

 acid, C 3 H 3 (COOH) 3 , an acid fairly widely distributed in plants. The 

 drug yields about 5 per cent, of ash. 



Aconitine, C^H^NOu (m.pt. 198 ), is the only one of these three that is 

 crystalline and extremely toxic, the lethal dose being about 0-00013 gm. per 

 kilo weight. It produces even in minute quantity the persistent tingling on 

 the tongue that characterises aconite root. It is very readily hydrolysed by 

 acids as well as by alkalies, yielding first acetic acid and picraconitine ; the 

 latter by further hydrolysis yields benzoic acid and aconine. Aconitine is, 

 therefore, acetylbenzoylaconine, and picraconitine is benzoylaconine. Aconitine 

 may be distinguished from benzoylaconine and aconine by its taste, by its melting 

 point, by its solubility in ether, and by its being readily crystallisable. 



Picraconitine (benzoylaconine), C 32 H 45 NO 10 , is amorphous, but yields 

 crystalline salts ; it has a bitter taste, is much less toxic than aconitine, and 

 is insoluble in ether. 



Aconine, C 25 H 41 NO 9 , is also amorphous, bitter, and insoluble in ether ; it 

 is practically non-toxic. 



The relation in which these alkaloids stand to one another may be made 

 clear by the following equations : 



O n + H 2 = CH 3 .COOH + C 32 H 45 NO 10 



aconitine acetic acid benzoylaconine 



C 32 H 45 N0 10 + H 2 = C 6 H 5 .COOH + C 25 H 4f NO 9 



benzoylaconine benzoic acid aconine 



The amount of total alkaloid present in the root appears to be 

 subject to great variation, from 0-2 to 1-5 per cent, having been 

 reported. No process has yet been devised by which the aconitine can 

 be accurately determined in the presence of the other alkaloids. That 

 portion of the total alkaloid that is dissolved by ether is, however, 

 mostly crystalline, and consists almost entirely of aconitine . The ether- 

 soluble alkaloid in aconite root of good quality ranges usually from 

 about 0-3 to 0-5 per cent. 



Uses. Preparations of aconite and its principal alkaloid, aconitine, 

 when applied to the skin, produce tingling followed by numbness ; 

 they are used in certain forms of neuralgia and rheumatism. Admin- 



