title: Oxanosine, a novel nucleoside from actinomycetes.
abstract: Oxanosine, a novel nucleoside, has been isolated from the culture filtrate of a strain of Streptomyces. The structure was determined to be 5-amino-3-beta-D-ribofuranosyl-3H-imidazo [4,5-d] [1,3]oxazin-7-one by X-ray crystallographic analysis and chemical studies. Oxanosine showed weak antibacterial activity on peptone agar; for example, Escherichia coli K-12 (MIC 12.5 mcg/ml). The antibacterial activity was antagonized by addition of guanine, guanosine and 5'-guanylic acid. Oxanosine inhibited the growth of HeLa cells in vitro (IC50 32 mcg/ml) and suppressed the growth of L-1210 leukemia in mice. The primary action of oxanosine appears to be inhibition of GMP-synthetase. Intravenous injection of 4 mg of oxanosine to mice does not show any toxic sign.
mesh_terms: D002455:Cell Division / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D004926:Escherichia coli / Q000187:drug effects; D006367:HeLa Cells / Q000187:drug effects / Q000502:physiology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D012263:Ribonucleosides / Q000302:isolation & purification / Q000494:pharmacology*; D013302:Streptomyces
chemical_list: D012263:Ribonucleosides; C032886:oxanosine