Metarhizin C

Producing organism
Tolypocladium album sp. RK17-F0007
Biological activity
selective cytotoxicity against osteosarcoma MG-63
Metarhizin C, a stereoisomer of BR-050 was isolated from a fungus Tolypocladium album RK17-F0007 through a screening program to search for new antitumor compounds. A structure of the isomer was determined by spectroscopic methods including detailed analysis of NOESY correlation and mass spectrometry, and found to be identical to that of 3-desacylmetarhizin A with the absolute structure. Previously, it had been isolated by Kikuchi et al and proposed as BR-050 including the stereo-structure. However, detailed analysis for the newly isolated isomer confirmed that 3-desacylmetarhizin A was not identical to BR-050. Therefore, we assigned it metarhizin C as a new BR-050 isomer. Metarhizin C showed selective cytotoxicity against osteosarcoma MG-63 cells in a glucose independent condition with IC50 value of 0.79 µg/ml, while > 30 µg/ml of IC50 value in a normal condition, and inhibited a mitochondrial respiration.
  • Nogawa T, Kawatani M, Okano A, Futamura Y, Aono H, Shimizu T, Kato N, Kikuchi H, Osada H.: Structure and biological activity of Metarhizin C, a stereoisomer of BR-050 from Tolypocladium album RK17-F0007
    J Antibiot, 72, 996-1000 (2019) PMID:31395970 [ doi: 10.1038/s41429-019-0229-1 ]
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