Coumarins 3-amino-6-hydroxy- from

The violet complex H[RuCl(H20)L2] (L = 8-amino-7-hydroxy-4-methyl-coumarin) has been isolated from the reaction of free ligand with RuClj at... 

Figure 11.4. PARP inhibitors nicotinamide, 5-methylnicotinamide,6-aminonicotinamide,picolin-amide, 3-methoxybenzamide, benzamide, 3-aminobenzamide, 2-aminobenzamide, 4-aminobenz-amide, coumarin, 3,4-dihydro-5-methylisoquinolinone (PD 1287631, 4-amino-l,8-naphthalimide, 8-hydroxy-2-methyl-3-hydroquina2olin-4-one, phenanthridinone, and 3-0-allQ lbenzamides. This figure is redrawn from Ref 33 and is used with permission.

Aminocoumarin antibiotics such as novobiocin, clorobiocin, and coumermycin A1 are derived from different Streptomyces species and show a very potent antibacterial activity by inhibition of DNA gyrase. Gyrase inhibitors block DNA replication, induce the SOS repair system, and eventually cause bacterial cell death (Figure 6.32) [151-154], These antibiotics possess a 3-amino-4-hydroxy-coumarin and a substituted deoxysugar noviose as common feature, which is essential for their biological activity. The biosynthetic gene clusters for novobiocin, chlorobiocin, and coumermycin A1 have been cloned in Streptomyces coelicolor M512 [155,156]. 

Fig. 1. A generalized scheme showing the kinds of secondary products that arise from the aromatic amino acids in higher plants. Several similarities are found in fungi and bacteria some fungi produce alkaloids ftom tryptophan and lignin-like materials from phenylalanine. Plant pathogenic fungi produce cinnamate and para and meta hydroxy phenyl-acetate from phenylalanine. Certain bacteria produce antibiotics and fluorescent pigments from metabolites in the shikimate pathway. Microorganisms are not known to produce coumarin, substituted coumarins, flavonoids and isoflavonoids.

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