Water-soluble alkaloids

The respective mixed-mode phase with cation-exchange properties is suitable for the analysis of a number of compound classes. The most important ones include alkaloids, water-soluble vitamins, sulfonamides, cephalosporins, catecholamines, diuretics, and xanthines, as well as a number of basic dyes. Figure 6.71 shows the separation of 10 different alkaloids, of which theophylline, theobromine, and caffeine are genuine constituents in beverages such as coffee and tea. In comparison to the classical separation on ODS phases, potentially interfering matrix components are better separated on a mixed-mode phase. 

The respective multimode phase with cation ejodiange properties is suitable for the analysis of a number of compotmd classes. The most important ones include alkaloids, water-soluble vitamins, sulfonamides, cephalosporins, cat-... 

In the commercial extraction of alkaloids from the drugs in which they exist, the powdered drug, or an alcoholic extract of it, is treated with an alkali such as ammonia or lime to liberate the alkaloid and the alkaloid is then extracted by means of an organic solvent. The crude material thus obtained is purified and finally crystallized either as the base itself or as its water-soluble salts. 

Karrer and Schmid have examined the water-soluble constituents in poppy straw after extraction of the alkaloids, and have recorded the presence of -hydroxybenzaldehyde, vanillin, -hydroxystyrene, meconin and the following acids fumaric, dZ-lactic, benzoic, -hydroxycinnamic, p-hydroxybenzoic, 2-hydroxycinchoninic, vanillic, phthalic, hemipinic and m-hemipinic, with a more highly unsaturated, carboxylic acid J, b.p. 170-570-02 mm., and three unidentified substances Fa , m.p. 271-2° Wx, m.p. 310° (dec.) and Q, m.p. 260° the two latter are free from nitrogen and contain no methoxyl. 

Papaverine crystallises in rhombic prisms or needles, m.p. 147°, [a]n 0°, is insoluble in water, soluble in hot alcohol or chloroform, and slightly so in cold alcohol or ether. It is a weak base for which, according to Wales, there is no satisfactory indicator, though bromophenol-blue has its colour change at the right point for this alkaloid. The hydrochloride, B. HCl, forms monoclinic plates, m.p. 225-6°, sparingly soluble in water (1 in 37 at 18°). The picrate forms quadratic plates, m.p. 186°. ... 

The process of isolation finally adopted by the former authors consists in precipitating as reineckates the water-soluble bases contained in a methyl alcoholic extract of the curare. The mixed reineckates are further purified, by solution in acetone and precipitation with water as often as may be necessary. The product so cleaned represents the bulk of the biological activity of the crude drug the mother liquors may contain curine (p. 374), which indicates a menisperm as one of the components of such curares. The mixed reineckates are then fractionated chromato-graphically over alumina and the components isolated as chlorides by the use of silver sulphate and barium chloride in succession. This process has been modified in detail by Schmid and Karrer, who have also found that with their curare, the more soluble reineckate fraction includes less potent quaternary alkaloids. 

Veratridine (amorphous veratrine), CggHgiOuN. This alkaloid, probably identical with Schmidt and Koppen s water-soluble amorphous veratrine and with the amorphous veratrines of Wright and Luffi and G. Merck, was named veratridine by Bosetti. Its isolation from commereial veratrine has been described by Blount.It is a colourless powder, m.p. 160-180°, + 8 0° (EtOH). The sulphate, B. H2SO4.9H2O,... 

With the death of the bean, cellular structure is lost, allowing the mixing of water-soluble components that normally would not come into contact with each other. The complex chemistry that occurs during fermentation is not fully understood, but certain cocoa enzymes such as glycosidase, protease, and polyphenol oxidase are active. In general, proteins are hydrolyzed to smaller proteins and amino acids, complex glycosides are split, polyphenols are partially transformed, sugars are hydrolyzed, volatile acids are formed, and purine alkaloids diffuse into the bean shell. The chemical composition of both unfermented and fermented cocoa beans is compared in Table 1. 

The water-soluble alkaloid kounidine (C2,H24N205) was isolated from G. elegans in 1936 (60), but the structure remains unknown. 

Allow the contents of the jar 24 hours to react the first time. The alkaloids (tryptamines) are converted into salts and become water soluble. Our elf-spice is now contained in the aqueous solution. 

The relative and absolute configurations of diepoxydicarbazoles involving the 2,6-dioxa-4,8-diazaadamantane system were determined in the course of a study on indole and indole alkaloids.242 Water-soluble azo, anthraquinone, and phthalocyanine dyes which are substituted by a 4-chloro-s-triazin-2-ylamino group can be quaternized with a l-aza-3-methyl-4,6,10-trioxa-adamantane unit in aqueous medium at 40 50"C.243 Dyes mixed with... 

Cocaine is derived from the coca plant Erythroxylon coca. This drug is a water soluble alkaloid that is readily absorbed through mucous membranes. Cocaine s activity is due... 

Cyanobacterial neurotoxins are small ringed alkaloids and have dramatic effects on various components of vertebrate neurons. They are all water soluble and are synthesized by several cyanobacterial genera (Table 5.1). The most commonly isolated neurotoxins are the paralytic shellfish toxins, although several other potent neurotoxic alkaloids are synthesized by freshwater cyanobacteria (Table 5.1). 

Alkaloids are found mainly in plants, and are nitrogenous bases, typically primary, secondary, or tertiary amines. The basic properties facilitate their isolation and purification. Water-soluble salts are formed in the presence of mineral acids (see Section 4.11.1), and this allows separation of the alkaloids from any other compounds that are neutral or acidic. It is a simple matter to take a plant extract in a water-immiscible organic solvent, and to extract this solution with aqueous acid. Salts of the alkaloids are formed, and, being water soluble, these transfer to the aqueous acid phase. On basifying the acid phase, the alkaloids revert back to an uncharged form, and may be extracted into fresh organic solvent. 

Tannins are water-soluble phenolic compounds which are usually extracted from plant material by hot water. After lignins, they are the second most abundant group of plant phenolics. Their tanning property is due to their capacity to combine with proteins. However, they can also complex with other polymers such as alkaloids, cellulose, and pectins. 

Camptothecin is a plant alkaloid obtained from the Camptotheca acuminata tree. It was first evaluated clinically, as a sodium salt, in the 1960s and 1970s, but was abandoned because of severe and unpredictable hemorrhagic cystitis (3,4). Irinotecan (CPT-11) and Rubetecan are semisynthetic, water-soluble derivatives of camptothecin possessing... 

True alkaloids derive from amino acid and they share a heterocyclic ring with nitrogen. These alkaloids are highly reactive substances with biological activity even in low doses. All true alkaloids have a bitter taste and appear as a white solid, with the exception of nicotine which has a brown liquid. True alkaloids form water-soluble salts. Moreover, most of them are well-defined crystalline substances which unite with acids to form salts. True alkaloids may occur in plants (1) in the free state, (2) as salts and (3) as N-oxides. These alkaloids occur in a limited number of species and families, and are those compounds in which decarboxylated amino acids are condensed with a non-nitrogenous structural moiety. The primary precursors of true alkaloids are such amino acids as L-ornithine, L-lysine, L-phenylalanine/L-tyrosine, L-tryptophan and L-histidine . Examples of true alkaloids include such biologically active alkaloids as cocaine, quinine, dopamine, morphine and usambarensine (Figure 4). A fuller list of examples appears in Table 1. 

The name alkaloid comes from the fact that a number of NPs were formd in the nineteenth century which were alkaline. These chemicals were shown to contain a nitrogen molecule, and when their structures were determined it was formd that the nitrogen was usually in a heterocyclic ring (a cyclic carbon skeleton with one or more nitrogen atoms in the ring—see Figure 3.9). The N is usually protonated at physiological pH, thus many of these molecules are polar and hence water soluble. 

---