biostudies-literatureMu YSpecific Research Project of Guangxi for Research Bases and TalentsScience and Technology Major Project of Guangxi35011-35019https://www.ebi.ac.uk/biostudies/studies/S-EPMC9042891biostudies-literatureUnknown11(55)Six oxazolomycins (1-6) were isolated from the fermentation broth of a soil-borne bacterial strain, <i>Streptomyces glaucus</i>. The structures of the new compounds, oxazolomycins D-F (1-3) and glaucumycins A, B (6a/6b), were elucidated by detailed spectroscopic data analysis. Oxazolomycins 1, 2, 4, and 5 demonstrated weak or modest cytotoxic activities against four human cancer cell lines, with IC₅₀ values ranging from 10.6 ± 1.7 to 89.5 ± 6.6 μM (or >100 μM). Further study showed that 4 caused S phase cell cycle arrest in SMMC7721 cells through down-regulating the protein expression of cyclin A2, CDK2. Meanwhile, 4 induced apoptosis in SMMC7721 cells through down-regulating the protein levels of Bcl-2, up-regulating the levels of Bax, and activating the cleavage of caspase-3.RSC advancesOxazolomycins produced by <i>Streptomyces glaucus</i> and their cytotoxic activity.PMC9042891AD18281066AA18242026Jiang YLi GMu YHan LTan JHuang XQu XLiu BJiang MLi LfalseOxazolomycins produced by <i>Streptomyces glaucus</i> and their cytotoxic activity.Six oxazolomycins (1-6) were isolated from the fermentation broth of a soil-borne bacterial strain, <i>Streptomyces glaucus</i>. The structures of the new compounds, oxazolomycins D-F (1-3) and glaucumycins A, B (6a/6b), were elucidated by detailed spectroscopic data analysis. Oxazolomycins 1, 2, 4, and 5 demonstrated weak or modest cytotoxic activities against four human cancer cell lines, with IC₅₀ values ranging from 10.6 ± 1.7 to 89.5 ± 6.6 μM (or >100 μM). Further study showed that 4 caused S phase cell cycle arrest in SMMC7721 cells through down-regulating the protein expression of cyclin A2, CDK2. Meanwhile, 4 induced apoptosis in SMMC7721 cells through down-regulating the protein levels of Bcl-2, up-regulating the levels of Bax, and activating the cleavage of caspase-3.2021-01-01T00:00:00Z2021 Oct2026-05-31T23:16:59.13Z2024-10-17T19:59:26.936ZS-EPMC90428913549474510.1039/d1ra06182h