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Phenanthridine modulator

The phenanthridine alkaloid lycorine (narcissine, galanthidine) (MD—Phe G5N C6) has a widespread occurrence and inhibits protein synthesis. Like lycorine, the structurally similar alkaloids dihydrolycorinine, haemanthamine, narciclasine, pretazettine and pseudolycorine also inhibit protein synthesis at the level of peptide bond formation. Galanthamine (lycorimine) (Phe C6N C40 C6 ), from daffodil bulbs but also of widespread occurrence, is both a nACh-R allosteric modulator and an inhibitor of AChE. Galanthamine is clinically employed in the treatment of Alzheimer s disease (dementia linked to deficiency in acetylcholine-mediated signalling in the central nervous system). [Pg.17]

Moreover, some plant metabolites, as the phenanthridine alkaloid extracts from Amaryllidaceae species, are particularly important for their chemotaxonomic relevance, pharmacological applications, the role in modulating some important physiological plant mechanisms, and their biological effects. Some reviews concerning these aspects have been published [9-16]. [Pg.582]

The Chi synthesis modulators that Rebeiz et al. (13, 14) used in conjunction with ALA could be divided into three categories A) enhancers of ALA conversion to porphyrins (2-pyridine aldoxime, 2-pyridine aldehyde, picolinic acid, 2,2 dipyridyl disulfide, 2,2 -dipyridyl amine, 4,4 dipyridyl, and phenanthridine), B) inducers of ALA biosynthesis and porphyrin accumulation (2,2 -dipyridyl and 1,10-phenanthroline), and C) inhibitors of MV PChlide synthesis (2,3-dipyridyl, 2,4-dipyridyl, 1,7-phenanthroline, and 4,7-phenanthroline). Compounds in group A did not cause significant porphyrin accumulation alone however, they enhanced dark conversion of exogenous ALA to porphyrins. This group was further subdivided into compounds that enhanced conversion of ALA to MV PChlide (2-pyridine aldoxime, 2-pyridine aldehyde, picolinic acid, and 2,2 -dipyridyl disulfide) and those that stimulated conversion to DV PChlide (4,4 dipyridyl, 2,2 dipyridyl amine, and phenanthridine). To qualify as an ALA biosynthesis and porphyrin accumulation inducer (category B), the compound had to cause these effects in the absence of ALA. Compounds in category C had to inhibit accumulation of MV PChlide with or without ALA. In most cases, in conjunction with ALA, the compounds stimulated DV PChlide accumulation compared to the ALA-treated control. [Pg.376]

The dual application of ALA with one or more chlorophyll biosynthesis modulators can result in selective herbicide action due to the four different greening patterns within the multibranched chlorophyll pathway that occur in plants. " The chlorophyll biosynthesis modulators are classified into three major groups depending on their mode of action enhancers of ALA conversion to tetrapyrroles (e.g., 2-pyridine aldehyde, picolinic acid, 4,4 -dipyridyl, phenanthridine, 2,2 -pyridylamine) inducers of tetrapyrrole accumulation (e.g., 1,10-phenanthroline, 2,2 -dipyridyl) and inhibitors of mono vinyl protochlorophyllide accumulation (1,7- and 4,7-phenanthroline, 2,3-dipyridyl, 2,4-dipyridyl). ... [Pg.138]


See other pages where Phenanthridine modulator is mentioned: [Pg.24]   
See also in sourсe #XX -- [ Pg.537 ]




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