Streptonigrin

DescriptionStreptonigrin is a phenylpyridylquinoline originally isolated from S. flocculus with diverse biological activities. Streptonigrin (2.5-12.5 μM) induces DNA cleavage by calf thymus topoisomerase II in a concentration-dependent manner. It induces phage production in S. typhimurium when used at concentrations ranging from 1 to 10 μg/ml. Streptonigrin (10 μg/ml) inhibits DNA synthesis in and reduces survival of S. typhimurium bacteria. Streptonigrin is bactericidal against E. coli in an iron-dependent manner, an effect that is blocked by the iron chelators deferoxamine and orthophenanthroline. Streptonigrin (40 nM) is cytotoxic to human HT-29 colon carcinoma cells but not to BE colon carcinoma cells in which NAD(P)H:quinone oxidoreductase is not expressed. Streptonigrin (0.001-0.1 μg/ml) inhibits mitosis and induces chromatin breaks in human leukocytes in a concentration-dependent manner. In vivo, streptonigrin (0.05 mg/kg, i.p.) increases the mean survival time in rats infected with Rauscher virus.

UsesStreptonigrin is an aminoquinone antitumour antibiotic. Its antineoplastic activity requires reductive activation by Xanthine-converting enzymes. It induces apoptosis by a mechanism involving NF-κB. DNA cleavage reaction and chromosome damage by Streptonigrin are influenced by the nature of the metal ion present and dependent on the production of free radicals. Its antibiotic activity is iron-activated. Streptonigrin from Streptomyces flocculus

UsesStreptonigrin is an unusual aminoquinone with broad biological activity against bacteria, fungi, nematodes, viruses and tumour cells. Streptonigrin acts as a bioreductive agent, highly dependent on interactions with metal ions, notably iron, and plays an important role in free radical production through redox cycling of NAD(P)H:quinone oxidoreductase (NQO1).