siomycin a

Siomycin A is a macrocyclic thiopeptide (peptide thiazole) antibiotic first isolated from *Streptomyces sioyaensis* and other Actinomyces, including endophytes from medicinal plants such as *Acanthopanax senticosus*.[1][3][5][7][10] It is characterized structurally by the presence of thiazole rings and thiopeptide features, and its molecular formula is C71H81N19O18S5 (CAS 12656-09-6). Siomycin A exhibits potent and selective antibacterial activity, primarily against Gram-positive bacteria, by binding to the 23S rRNA of the 50S ribosome subunit and thereby inhibiting protein translation.[1][3][5][7] In mammalian cells, siomycin A inhibits the transcription factor Forkhead box M1 (FoxM1), suppressing FoxM1-regulated gene expression (including Cdc25B, survivin, cyclin B, Aurora B kinase, and CENPB), resulting in cell cycle arrest, reduced proliferation, and induction of apoptosis in cancer cell lines.[1][3][5][7] Siomycin A also induces reactive oxygen species (ROS) generation and mitochondrial dysfunction leading to apoptosis in tumor cells but shows limited toxicity to normal fibroblasts, suggesting selectivity towards malignant cells.[5][10] It is under preclinical investigation for anticancer potential, especially targeting FoxM1-driven tumors.

Other names

MutabilycinMutabillicinSporangiomycinAntibiotic 6741-21Antibiotic6741-21Antibiotic-6741-21Salomycin AAJY431WN1JAJY-431WN1JAJY 431WN1J