Strychnine alkaloids

The convulsant alkaloid strychnine from the Indian tree Strychnos nux vomica is highly toxic. Strychnine... 

Strychnine and brucine are extremely toxic alkaloids. Strychnine binds itself to receptor sites in the spinal cord and accommodates glycine. Brucine is a dimethoxy form of strychnine, and is less toxic. 

A robust TLC separation of the seven alkaloids (strychnine, quinine, heroin, noscapine, caffeine, papaverine and narceine) is difficult to obtain. The solutes used have different properties and can therefore not be separated trustworthy for all possible values of relative humidity and temperature. 

Optica] resolution of these and related carboxylic acids were achieved using salt formation with alkaloids (strychnine, brucine, cinchonidine) 33,39,44 or with optically active amines [1-phenyl- or l-( 3-naphthyl)ethylamine]4o,44). The following rotations [a]D have been reported [8]paracyclophanecarboxylic acid (13) +18° (chloroform)441 [10]homologue (14) +80° (chloroform)39 and +67° (chloroform)40 its methyl-derivative (75) —28° (methanol)44 . Dioxa[10]paracyclophanecarboxylic acid (16) + 104° (ethanol)36 and bromo-dioxa[12]paracyclophanecarboxylic acid (79) —37° (acetone)33). 

N.A. Indole alkaloids, strychnine, loganin, chlorogenic acid.99 This herb is toxic. A stimulant for nervous system, a homeopathic remedy for digestive problems, sensitivity to cold, and irritability. 

Alkaloids are compounds of biosynthetic origin that contain nitrogen, usually in a heterocyclic ring. These compounds are produced by plants in which they are usually present as salts of organic acids. They tend to be basic and to have a variety of physiological effects. One of the more notorious alkaloids is cocaine, and alkaloidal strychnine is a deadly poison. The structural formulas of these compounds and three other alkaloids are given in Figure 15.10. 

Of the methods for the separation of racemic mixtures into dieir components one of the most useful is the formation of salts with optically active acids or bases. Early attempts to apply this method to the amino acids failed, since these compounds are not only weak acids, and therefore form rather unstable salts widi bases, but are also weak bases, and form unstable salts with acids. Fischer overcame this difficulty by converting the amino acids into their benzoyl derivatives, which he found to be stronger acids and so formed stable salts with optically active bases such as the alkaloids strychnine and brucine. Ordinary methods of benzoylation failed in this instance, but good yields were obtained in the presence of sodium bicarbonate. 

Hyoscyamine, scopolamine, and other tropane alkaloids (AA) acetylheliosupine and some other pyrrolizidine alkaloids arecoline (A) berbamine, berberine, and other isoquinoline alkaloids dicentrine and other aporphine alkaloids strychnine, brucine cryptolepine (AA) sparteine and other quinolizidine alkaloids (A) pilocarpine (A) emetine himbacine and other piperidine alkaloids (A) imperialine (AA) muscarine (A)... 

A number of alkaloids are known whose structures are more or less similar to those of endogenous neurotransmitters. Targets can be the receptor itself, the enzymes which deactivate neurotransmitters, or transport processes, which are important for the storage of the neurotransmitters in synaptic vesicles. Alkaloids relevant here include (Table IV) brucine, ergot alkaloids, eseridine, serotonin, physostigmine, gelsemine, j8-carboline alkaloids, strychnine, yohimbine, berberine, bicuculline, bul-bocapnine, columbamine, coptisine, coralyne, corlumine, ephedrine, ga-... 

Ext. Nucis Vomics (extract of nux) The seeds of Stryctms nux vomica used in a similar manner as its alkaloid strychnine. 

The dried ripe seeds of Strychnos nux-vomica (nux vomica) contain the alkaloids strychnine and brucine, together with traces of other alkaloids. 

Aconitine,opium-, tropane alkaloids, strychnine,quinine, caffeine, emetine,cephael ine Sulfanilamide phenytoine, phenobarbital Identification in pharmaceuticals (Fig. 7. 14) Partisil PXS 5/25 250x4.6 Et-0 sat. with 50-100% H,0 + 0.05-0. DEA z 00 ro... 

The ripe fruit is similar in shape, colour and size to a small orange and has jelly-like, white, bitter fruit flesh, with 4-5 flat grey seeds. The active ingredients in the seeds are the indole-alkaloids strychnine and brucine both have a very bitter taste. 

A surprising number of drugs bear only a tenuous (or no ) structural similarity to the natural agent/ transmitter. An excellent illustration is the well-known indole alkaloid strychnine, which is a competitive antagonist of the CNS neurotransmitter glycine. 

American poisonous mixture called curare. Curare is derived from certain members of the genus Strychnos, and contains a number of toxic alkaloids (strychnine being a famihar name for such an alkaloid). Thus, enzymes in glycolysis and the tricarboxylic cycle proper are of fundamental concern, for their blockage or inhibition could prove fatal. Inhibitors for enzymes involved in the carboxylic acid cycle are listed in Appendix B of Hoffman (1999). 

Glycine (aminoacetic acid) is the simplest of the amino acids. Because of the many metabolic pathways in which it is found, its central inhibitory neurotransmitter properties went unrecognized until its spinal cord distribution was examined. The convulsant alkaloid strychnine is believed to block postsynaptic glycine receptors. Presynaptic release impairment may also be part of its action. While the peripheral chemical reactions of glycine are reasonably well known, its conversion to pyruvate via serine—the biochemistry of gly in central neuronal fibers—is still not fully understood. High-affinity uptake systems for gly (and several other transmitter amino acids) were soon demonstrated in CNS tissue. Serine, of course, acts as a precursor to gly. Whether it also has inhibitory neurotransmitter properties is in doubt. 

Strychnos alkaloids Strychnine and brucine Adsorption Silica gel Diethyl ether/ methanol (90 10)... 

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