Alkaloids other compounds

Alkaloid Other Compounds Aims Stationary Phase Column Dim. LxID mm Mobile Phase Ref. 

ALKALOIDS OTHER COMPOUNDS AIMS STATIONARY PHASE COLUMN DIM. MOBILE PHASE LxID mm REF. 

HPLC ANALYSIS INDOLE ALKALOIDS IN PHARMACEUTICAL PREPARATIONS ALKALOIDS OTHER COMPOUNDS AIMS... 

Alkaloids are compounds that contain nitrogen in a heterocyclic ring and are commonly found in about 15-20% of all vascular plants. Alkaloids are subclassified on the basis of the chemical type of their nitrogen-containing ring. They are formed as secondary metabolites from amino acids and usually present a bitter taste accompanied by toxicity that should help to repel insects and herbivores. Alkaloids are found in seeds, leaves, and roots of plants such as coffee beans, guarana seeds, cocoa beans, mate tea leaves, peppermint leaves, coca leaves, and many other plant sources. The most common alkaloids are caffeine, theophylline, nicotine, codeine, and indole... 

A representative series of enantiomerically pure alkaloids and other compounds having known biological activity was synthesized using the above described strategy by the group of Prof. Denmark (Chart 3.19). 

Nyembo et al. [15] proposed in 1978 that the amino acid 34 and other compounds of general structure 35> known as phlegmarines, the stereochemistry of which is not specified, may be intermediates involved in the biosynthesis of Lycopodium alkaloids. 

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. 

Extracts of plants have been used as insecticides by humans since before the time of the Romans. Some of these extracts have yielded compounds useful as sources (e.g., pyrethrins, rotenoids, alkaloids), others as models (e.g., pyrethrins, physostigmine) of commercial insecticides. Recent technological advances which facilitate the isolation and identification of the bioactive constituents of plants should ensure the continued usefulness of plant compounds in commercial insect control, both as sources and models of new insect control agents and also as components in host plant resistance mechanisms. The focus in this paper will be on several classes of compounds, including limonoids, chromenes, ellagitannins, and methyl ketones, which were found to be components of the natural defenses of both wild and cultivated plants and which may be useful in commercial insect control. 

This compound exhibits the same relationship to (3-D-fructofuranose as 1-deoxy-nojirimcin does to D-glucopyranose. In 1979, a polyhydroxyindolizidine alkaloid was isolated from the poisonous fruit of Castanospermum australe, a handsome Australian indigenous tree, and coined castanospermine (8) after its source.28 A compound subsequently isolated from the seeds of this plant was the pyrrolizidine australine (9),29 also found in Alexa leiopetala,30 along with other compounds. These discoveries increasingly supported the hypothesis that imino sugars and their structural relatives might be a fairly common family of natural products, and their widespread... 

Detractors of herbal medicine use have legitimate concerns about dosage variability, possible toxicity and adulteration, herb-drug interactions, and above all, lack of FDA regulation. Far from being intrinsically harmless, many pharmacologically active plant alkaloids and other compounds are natural defensive poisons their very effectiveness may be an unanticipated consequence of their adaptive toxicity to grazing animals and... 

Intercalation has been demonstrated with a number of other compounds having a polycyclic aromatic system and groups capable of forming hydrogen bonds. Among such compounds are the antibacterial 9-aminoacridine, the antimalarials mepacrine and chloroquine, the veterinary trypanocide ethidium (246), the thioxanthone lucanthone (247 R = Me) and its more active metabolite hycanthone (247 R = CH20H), which are used in the treatment of schistosomiasis, and the antineoplastic alkaloid ellipticine (248). A number of antibiotics, including the actinomycins, echinomycin and bleomycin, also intercalate. 

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