Lappaconitine

A. septentrionale, Koelle. Lappaconitine, septentrionaline and cynocto-nine (p. 686). 

Oxidation of lappaconitine and elatine alkaloids leads to de-ethylation by a Cope reaction, with the formation of nitrones (Scheme 2.15) (94). 

Lappaconitine (2) this compound is 40 times less toxic than aconitine (1). In anesthetized rabbits it induced cardiac arrhythmias, preceded by bradycardia and fall in blood pressure [11]. 

The roots of the same plant has yielded one new alkaloid together with two known compounds lycoctonine and lappaconitine. The structure of the new alkaloid (cochlearenine) (11) is quite similar to that of cochleareine (9). Due to this resemblance the stracture determination of the compound 11 was carried out not only by spectral data but also by single-crystal x-ray diffraction studies [19]. 

Studies of the arrhythmogenic effects and the effects on heart rate of aconitine (14), X-desacetyl-lappaconitine (7), lappaconitine (6), lycoctonal (13), lycoctonine (12), lappaconine (15), avadharidine (9), lycaconitine (10), anthranoyl-lycoctonine (8), and cashmiradelphine (septentriodine) (11) were also reported.8 The alkaloids (6), (7), and (15) were found to be arrhythmogenic... 

Lappaconitine (6) R = COC6H4-2-NHAc JV-Desacetyl-lappaconitine (7) R = COC6H4-2-NH2 Lappaconine (15) R = H... 

Yang, F.Q. Ito, Y. Preparative separation of lappaconitine, ranaconitine, A-deacetyllappaconitine and A-deacetyhana-conitine from crude alkaloids of sample Aconitum sino-montanum Nakai by high-speed countercurrent chromatography. J. Chromatogr. A 2002, 943 (2), 219-225. Marston, A. Hostettmann, K. Countercurrent chromatography as a preparative tool applications and perspectives. J. Chromatogr. A 1994, 658 (2), 315 - 341. 

Yang, F.Q. Ito, Y. pH-Zone-refining countercurrent chromatography of lappaconitine from Aconitum sinomon-tanum Nakai I. Separation of prepurified extract. J. Chromatogr. A 2001, 923 (1-2), 281-285. 

Shaheen et al. (2005) reported lycoctonine-type norditerpenoid alkaloids isolated from the aerial parts of Aconitum laeve Royle, swatinine, delphatine, lappaconitine, puberanine, and N-acetylsepaconitine [48]. They performed and reported the anti-inflammatory, antioxidant, and tyrosinase inhibition studies of all these compounds, in which lappaconitine (IC50 = 93.33 p,M) and puberanine (IC50 = 205.21 xM) were found to be active against the enzyme tyrosinase [48]. 

In another report Sultankhodzhaev et al. discussed the tyrosinase inhibitory potentials and structure-activity relationships of 15 diterpenoid alkaloids with the lycoctonine skeleton, and their semisynthetic derivatives [49]. At least three of them, lappaconitine hydrobromide (44, IC50 =... 

Fig. 7 Structures of the tyrosinase inhibitory diterpenoid alkaloids lappaconitine hydrobromide (44), methyllycaconitine perchlorate (45), and aconine (46) [49]...

Lappaconitine (C32H44N2O8). This is the iV-acetylanthranilic ester of a tri-hydroxy-trimethoxy base, lappaconine (C23H37O6N). A recent chemical study located some of its functions on a presumed lycoctonine skeleton. The sequence in equation (2) uniquely located the vicinal glycol group if this skeleton were correct. A methoxy-group was placed on C-14 because of its exceptional ease of hydrolysis (presumably in the diketone). However, )3-methoxy elimination... 

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