Serpentinine

R. serpentina Benth. Ajmalicine, ajmaline, ajmalinine, serpentine, serpentinine (Siddiqui and Siddiqui ). From a geographical variety of the species, Moajmaline, neoajmaline and unnamed alkaloids, m.p. 220° and m.p. 234 (S. Siddiqui ). From the same species van Itallie and Steenhauer isolated alkaloids B, C and A (rauwolfine) which may be identical with Siddiqui s serpentine, aimalinine and ajmaline respectively. 

R. vomitoria Afz. (sample from French Guinea). Ajmaline, iso-ajmaline, ajmalicine, ajmalinine and possibly serpentinine, cf. R. serpentina (Paris ). 

Raymond-Hamet has given much attention to the action of the Rauwolfia alkaloids. Using Siddiqui s ajrhalinine, he found that it provokes hypotension accompanied by renal dilatation and exerts a true sympathi-colytic action. 1 Ajmaline and serpentine also induce hypotension and a decrease in intestinal action serpentinine diminishes the renal constrictive action of adrenaline, but does not alter its hypertensive effects. ... 

Methoxy-3,4,5,6-tetradehydrocorynantheol (286), 3,4,5,6,18,19-Hexade-hydroochropposinine (287), 3,4,5,6-Tetradehydrositsirikine (288), Alstonine (289), the no-name-alkaloid (290) (Mitragyna speciosa) (98T8433), 3,4,5,6-Tetradehydropalicoside (291) and its methylester which were isolated recently from Strychnos mellodora (99P1171), Serpentine (292), and Serpentinine (293) are known representatives of this class of alkaloids. 

Attention should also be drawn to recent publications on the isolation of a new hypotensive factor from the roots of R. serpentina (120). In these publications, the separation of the crude alkaloids from fresh undried R. serpentina roots into four alkaloidal complexes is reported. The first three fractions have been named resajmaline, ajmalexine, and serpajmaline, respectively. The serpajmaline fraction is said to be therapeutically active and also is claimed to contain serpentinine, serpentine, ajmaline, and two unknown substances, one of which is probably reserpiline. This fraction is said also to be free from reserpine and to be much more potent in its hypotensive activity than reserpine, but to lack reserpine s sedative and central nervous depressant action. However, a later pharmacological investigation of an authentic water-soluble serpajmaline fraction (alkaloids present as salts) demonstrated that the type of antihypertensive activity observed closely resembles that of serpentine and serpentinine (121). This conclusion receives support from a chemical study of this fraction in which serpentinine, ajmaline, and tetraphyllicine were obtained in a pure state (121). 

Alstonia constricta F. Muell. (36) alstonine, R. vomitoria (37) aricine, Aspidosperma marcgravianum Woodson (37) reserpiline, R. decurva Hook. (38) isoreserpiline, R. cambodiana Pierre (39), R. decurva, and Ochrosia poweri F. M. Bailey serpentinine, R. vomitoria (37) and R. javanica (34). 

The deep-yellow base serpentinine, first isolated from Rauwolfia serpentina Benth. ex Kurz and later from other related species, possesses the molecular formula C42H44O6N4, based on elemental analyses and molecular weight determinations. The anhydrous compound is hygroscopic and crystallises with 1—2 moles of water. The analyses of a number of salts agree with this formula. 

The u.v. spectrum of serpentinine corresponds to an addition of the absorption of serpentine (244) or alstonine (245) to that of yohimbine (246). In accordance with this, serpentinine in aqueous dimethylformamide exhibits two pK a values of 6.0 (tetrahydro-)5-carboline part) and 10.6 (anhydronium base part) pK of... 

A strong band at 3330 cm in the i.r. spectrum (CHCI3) of serpentinine is due to an indolic NH group serpentine (244) shows no such band. 

Potassium fusion of serpentinine gives indole-2-carboxylic acid and 1-oxo-... 

From these observations and the fact that serpentine (244) and ajmalicine [stereoisomer of tetrahydroalstonine (247)] also occur in Rauwolfia serpentina the formula (250) has been proposed for serpentinine. ... 

Unfortunately the mass spectrum of serpentinine shows only peaks corresponding to thermal decomposition products. 

The 220 MHz n.m.r. spectrum of serpentinine in dimethyl sulphoxide shows the presence of ten aromatic protons. Amongst these signals can be recognised fohr... 

CHCI3) of serpentinine also shows a hydrogen-bonded NH (3330 cm ) the standard NH group in heteroyohimbine types absorbs at 3445-3475 cm. ... 

The constitution (253) proposed for serpentinine requires further confirmation. 

In the cases of bisindole alkaloids which possess only one substituted aromatic position the seven-proton aromatic region of the n.m.r. spectrum needs to be well enough resolved to allow analysis. At 100 MHz this is the case for alkaloids of the pycnan thine group (Section 11) and pleiomutine (230) (Section 13, p. 279). The j5-carboline derivative serpentinine (253) contains ten aromatic protons and the 100 MHz spectrum yields little information in contrast, the 220 MHz spectrum... 

The information to be gained from a mass spectrum is naturally dependent on structure. Serpentinine (253) gives an extremely complicated, worthless spectrum in which no molecular ion appears. The spectrum of C-curarine dichloride (54) shows only the molecular ion of the bisnor-base, while for calebassine dichloride (55) only the peaks corresponding to the loss of one and two molecules of water from the bisnor-base are observed. The other curare alkaloids also yield spectra which show a lack of fragment ion peaks they share this characteristic with strychnine. 

Serpentinine has been found to occur in the root bark of... 

Rauwolfia serpentina Benth. is the source of several related alkaloids. Ajmaline, ajmalicine, ajmalinine, serpentine, serpentinine, isoajmaline, and neoajmaline have been identified. Ajmaline and serpentine have been given provisional structural formulas (81, 82). Other members of the Apocynaceae yield alkaloids of similar properties. Although Rauwolfia preparations have been used in Ayurvedic medicine for hypertension, there appear no indications that they have been used in clinical cardiac arrhythmia. Yet, incomplete pharmacologic studies indicate properties for these alkaloids which should prompt additional studies toward their possible use in auricular fibrillation. 

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