Alkaloids rescinnamine

The closely related alkaloids rescinnamine (XLV, R = 3,4,5-trimethoxy-cinnamyl Fig. 3) [982, 1030-1043] and deserpidine (11-desmethoxyreserpine) [982,1036-1039,1042,1044-1047] exhibit similar, though less potent, sedative and hypotensive properties to reserpine and they have seen clinical apphcation. In the synthetic compound methoserpidine the hypotensive properties are free from accompan5dng sedation provided only moderate doses are given [1048 to 1050], while the reserpic acid di-ester syrosingopine, exerts a mild h3 otensive effect with practically no accompanying sedation [1050-1057]. 

In the class of the butyrophenones, which has yielded a number of interesting psycho-active agents [119] - chiefly as a result of research done in the Janssen laboratories-two hypotensive compounds are also worth mentioning. They are the co-piperidino-butyrophenone (XII)-which, combined with the Rauwolfia alkaloid rescinnamine and the benzyl-piperazine trimetazidine, is marketed... 

The alkaloid reserpiae [50-55-5] which is isolated from the roots of Kauwoljia serpentina T., contains a gaUate trimethyl ether moiety. Reserpiae is used as an antihypertensive and a tranquilizer. A vinylogue of reserpiae, rescinnamine [24815-24-5] is also an antihypersensitive (75). Methoxsalen [298-81-7] (8-methoxypsoralen 7JT-9-methoxy-furo [3,2- ] [l]benzopyran-7-one) (21), a furocoumatia that occurs ia plants, eg, l eguminosae and Umbelliferae is used ia the treatment of vitiligo, as a suntanning promoter, and as a sunburn protectant. It is also available by synthesis (76). 

Alkaloids, e.g. reserpine, rescinnamine 105 C, 2 h Induced fluorescence (Xn > 500 nm, cut off filter). Possibly formation of 3-dehydro derivatives. [19]... 

The previously known reserpine-type alkaloids (3) are shown below. They are reserpine (109), deserpidine (110), rescinnamine (111), veneserpine (112), pseudoreserpine (113), raunescine (114), rescidine (115), raugustine (116), and isoraunescine (117). It should be mentioned that all reserpine-type alkaloids are trisubstituted at ring E and that the substituents at C-16, C-17, and C-18 are all in equatorial positions on the epiallo yohimbane ring system existing predominantly... 

N.A. Rauvolfia serpentina (L.) Benth. Indole alkaloids, reserpine, rescinnamine, ajmaline, yohimbine.99 Regulate hearbeat, treat high blood pressure and anxiety. Sedative and depressant effect on sympathetic nervous system. 

In 1918 the traditional Indian remedy rauwolfia was reported to be useful in the treatment of hypertension. Reexamination of this material led to the isolation of reserpine (28 R1 = Me, R2 = 3,4,5-trimethoxybenzoyl) which was shown in 1952 to have hypotensive and tranquilizing effects. Other alkaloids such as deserpidine (28 R1 = H, R2 = 3,4,5-trimethoxybenzoyl) and rescinnamine (28 R1 = Me, R2 = 3,4,5-trimethoxycinnamoyl) were later isolated. They are useful when alternative, more potent drugs are not well tolerated. 

The oxidation of primary and secondary alcohols by stable organic nitroxyl radicals has been reviewed.111 The kinetics of reactions of alkanes and arenes with peroxynitrous acid suggest the participation of the same active oxidizing species in both gas and aqueous phase HOONO or its decomposition product OONO. 112 The oxidation of the alkaloids reserpine and rescinnamine by nitric acid has been studied.113... 

Carbocyclic variants related to ajmalicine such as yohimbine are likely to arise from dehy-drogeissoschizine by the mechanism indicated in Figure 6.77. Yohimbine is found in Yohimbe bark (Pausinystalia yohimbe, Rubiaceae) and Aspidosperma bark (Aspidosperma species Apocy-naceae) and has been used in folk medicine as an aphrodisiac. It does have some pharmacological activity and is known to dilate blood vessels. More important examples containing the same carbocyclic ring system are the alkaloids found in species of Rauwolfla, especially R. serpentina (Apocynaceae). Reserpine and deserpi-dine (Figure 6.78) are trimethoxybenzoyl esters of yohimbine-like alkaloids, whilst rescinnamine is... 

Rescinnamine (Moderil) is an alkaloid of the alseroxylon fraction of Rauwolfia root. Syrosingopine (Singoserp) is a preparation made from reserpine by hydrolysis and... 

Active Constituents Reserpine, rescinnamine, yohimbine, ajmaline, serpentine (indole alkaloids). 

The occurrence of reserpine has been reported from all Rauwolfia species, with the exception of about half a dozen in which it is probably present in minute amounts. Renoxidine, the A-oxide of reserpine, has been isolated from R. vomitoria, R. serpentina, and R. canescens, and it may not be a natural product, since it could have been derived by autoxi-dation of the tertiary base which is abundant in these plants. If it was an artifact, the occurrence of other analogous A-oxides should have been noted, but so far the only other recognized case is raujemidine A-oxide, which is found along with the parent alkaloid, raujemidine (a minor base of R. canescens). In contrast to reserpine, deserpidine and rescinnamine are of restricted distribution, each being recognized so far in about ten species only. 

The root of Rauwolfia serpentina (snakeroot) contains numerons alkaloids, of which reserpine and rescinnamine are said to be the most active as hypotensive agents (1). 

Reserpine. which is the major active constituent of Rauwol-fia, was isolated in 1952 and is a much weaker base than the alkaloids just mentioned. Reserpinuid alkaloids are yo-himbinc-like ba.ses that have an additional functional group on C-18. Only three naturally occurring alkaloids possess reserpine-like activity strong enough for use in treating hypertension re.serpine. deserpidine. and rescinnamine. 

Settimj et al.6 described a gas chromatographic method for the estimation of reserpine and rescinnamine involving alkaline hydrolysis of the alkaloids and subsequent esterification of the acids formed by means of diazomethane. Reserpine gave quantitatively 3,4,5-trimethoxyben-zoic acid methylester, whereas the trars-3,4,5-trimethoxycinnamic acid methylester, which should be expected for rescinnamine, was partly isomerized to the cis-trimethoxycinnamic acid methylester or formed an adduct with a molecule of methanol, yielding 3-methoxy-3-(3,4,5-tr1-methoxyphenyl) propionic acid methylester. 

In the rootbark of R. serpentina more than 50 indole alkaloids occnr. Only font have a hypotensive effect reserpine, rescinnamine, deserpidine and serpentine. 

According to their mode of action the Rauvolfia-alkaloids can be divided into two gronps the centrally acting reserpine, rescinnamine, and deserpidine and the peripherally acting yohimbine, raubasine and ajmaline. The blood pressure lowering effect is dne to an inhibition of the sympathomimetic effects in the autonomic nervous system and has a long latency and duration. The effect is dne to depletion of the serotonin and... 

The use of reserpine, rescinnamine, and deserpidine as mild antihypertensives, mostly in combinations, has become a standard treatment of today. The search for additional antihypertensive plant alkaloids which set in after the discovery of reserpine has not yielded any great results. Some extracts or crystalline material... 

Rescinnamine, a rauwolfia alkaloid with peripherally acting adrenergic-blocking effects (1 mg p.o. daily), is used in mild to moderate hypertension. 

Rauvolfia alkaloids are prepared in 0.5% alcoholic solution, and 10(l1 is applied for TLC, e.g. reserpine, rescinnamine, rauwolscine, ajmaline, serpentine. 

Reserpine/rescinnamine Two to three alkaloids, e.g. rauba,sine... 

The determination of the pJC values of reserpine and rescinnamine by spectrophotometric methods is described. The partition studies of the alkaloids at different concentrations of chloroform and either O.IM sulfuric acid or O.IM phosphoric acid are given."... 

The pharmacological properties of deserpidine are similar to those of reserpine, causing sedation and tranquilization. Toxic effects from high doses include drowsiness, depression, nansea, diarrhea, abdominal cramps, and hypotension. It is less toxic than reserpine. However, the poisoning effects may be greater than those of other Rauwolfia alkaloids, such as rescinnamine. An oral LD50 value in mice is 500 mg/kg. 

Three alkaloids from Rauvolfia species have industrial interest aj-maline (38), reserpine (39), and rescinnamine. Ajmaline is used for its antiarrhythmic activity, reserpine and rescinnamine for their antihyper-... 

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