| Radix Aconiti, Radix Aconiti Kusnezoffii and Radix Aconiti Lateralis Preparata are traditional Chinese herbs which have extensive activities in anti-inflammatory, abirritation and anti-rheumatism. At the same time, they are well known for their acute and high toxicity, for example, in the causation of severe arrhythmias leading to death. Aconitine, Mesaconitine and Hypaconitine are pharmacologically improved to be the main active ingredients and toxic ingredients as well in the herbs. So, it is very necessary to research the metabolism and distribution of Aconitine, Mesaconitine and Hypaconitine. The aim of this work is to investigate the Metabolism and tissue distribution of them in vivo using the advanced LC/MSn and LC/MS/MS methods.1 The fragmentation pathway of Aconitine, Mesaconitine and HypaconitineThis work explained formation of main diagnostic fragment ions by using LCQ mass spectrometer and shown that [M+H-60]+ was specifically relevant to C8-acetoxyl group, [M+H-18]+ to C3-hydroxyl group and [M+H-60-32-28]+ to C15-hydroxyl group. At the same time, we also discuss the fragmentation sequence of main groups and deduced that C8-acetoxyl group is the first active group in fragmentation, C1-methoxy group the second and C6- methoxy group the third。2 Identification of the metabolites of Aconitine, Mesaconitine and Hypaconitine in rabbits The characteristic fragmentation of Aconitine, Mesaconitine or Hypaconitine wereobtained by analyzing their behavior in multi-stage MS(Msn). The fragmentation pathways can provide theoretical support to help us to identify the infinite structure of metabolites. Metabolites in the gastrointestinal tract, feces, urine and bile of rabbits administrated a single oral dose of 2mg·Kg-1 Aconitine, Mesaconitine or Hypaconitine were investigated respectively. A total of 97 metabolites were found except the unchanged drug. A number of 33 metabolites of aconitine were analyzed in 15 kinds as fellows: (1)Metabolites which MW less 14 than aconitine (aMD14-1～aMD14-6), we deduced that aMD14-1, aMD14-3 or aMD14-6 were demethylate of methoxy group in C1, C6 or C16; aMD14-2 and aMD14-4, one was demethylate of methoxy group in C18 and the other can not be identified; aMD14-5 was 8-formyl-14-benzoyl-aconine. (2)Metabolites which MW more 16 than aconitine (aMP16-1～aMP16-6), we deduced that aMP16-1 or aMP16-3 were 3′-hydroxyl aconitine or 4′-hydroxyl aconitine; aMP16-6 was 2′-hydroxyl aconitine; aMP16-4和aMP16-5 can not be identified; aMP16-2 may be a produce of hydroxylation occurred in methoxy group. (3)Metabolite which MW less 42 than aconitine (aMD42), we deduced it as 14-benzoyl-aconine. (4)Metabolite which MW less 104 than aconitine (aMD104), we deduced it as 8-acetyl -aconine. (5)Metabolites which MW less 30 than aconitine (aMD30-1～aMD30-5), aMD30-3 was deduced as indaconitien, aMD30-5 was deduced as deoxyaconitine and others can not be identified. (6)Metabolite which MW more 28 than aconitine (aMP28), we deduced it as 8- butyryl -aconine. (7)Metabolites which MW more 30 than aconitine (aMP30-1, aMP30-2). Their structures can not be deduced. (8)Metabolites which MW more 182 than aconitine (aMP182-1 , aMP182-2). They were deduced as 8-pentadecanoyl-14-benzoyl-aconine or 8- (13-methyl-tetradecanoyl)-14-benzoyl- aconine. (9)Metabolites which MW more 196 than aconitine (aMP196-1, aMP196-2). They were deduced as 8-palmityl -14-benzoyl-aconine or 8–(14-methyl-pentadecanoyl)-14-benzoyl- aconine. (10)Metabolite which MW more 224 than aconitine (aMP224). It was deduced as 8-stearoyl-14-benzoyl-aconine. (11)Metabolites which MW more 316 than aconitine (aMP316-1 and aMP316-2). Their structures can not be deduced. (12)Metabolites which MW more 168 than aconitine (aMP168-1, aMP168-2). They were deduced as 8-myristoyl-14-benzoyl- aconine or 8-(12-methyl-tridecanoyl)-14-benzoyl-aconine. (13)Metabolite which MW more 218 than aconitine (aMP218). It was deduced as 8-linolenoyl-14-benzoyl-aconine. (14)Metabolite which MW more 220 than aconitine (aMP220). It was deduced as 8–linoleoyl- 14-benzoyl-aconine. (15) metabolites which MW more 222 than aconitine (aMP222-1, aMP222-2). It was deduced as 8–oleoyl-14-benzoyl-aconine or 8-(11-methyl- jecericanoyl)- 14-benzoyl-aconine. Mesaconitine and Hypaconitine have the similar metabolism pathways with the Aconitine, and their metabolites were identified by analyzing the chromatography and mass spectra and comparing with reference substance.3 Tissue distribution of Aconitine, Mesaconitine and Hypaconitine in rabbitsA sensitive LC/MS/MS method was development with MRM mode to simultaneously determine Aconitine, Mesaconitine and Hypaconitine in biological samples of rabbits. The tissue distribution of Aconitine, Mesaconitine and Hypaconitine was investigated at 4 h Post-dose in rabbits. The result shows that the order of the concentration of Aconitine, Mesaconitine and Hypaconitine for high level to light level in the seven main tissues all are: gallbladder, liver, spleen, kidney, heart, lung, brain.
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