O-β-D-glucopyranoside (8) by spectroscopic methods including 1 Hand 13 C-NMR and HR-MS experiments, and by comparison with literature values. Compounds 1-7 are reported for the first time from Astragalus taxa. All of the compounds were tested for their cytotoxic activities against a number of cancer cell lines. Among them, only 6 exhibited significant activity against human colon carcinoma (HT-29) at 2.69 M concentration.
One hundred and twenty-six mesophilic Actinomycete cultures were isolated from the Aegean region of Turkey. The antimicrobial activities of pure isolates were tested using the agar-plaque method. Based on high antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA) and Escherichia coli O157-H7 (E. coli), the isolate M-33-5 was selected for bioactivity-guided isolation. Fermentation, followed by solvent partition (H 2 O-EtOAc, H 2 On -BuOH), showed that the highest activity was present in the EtOAc extract. By using chromatographic methods, two bioactive compounds were isolated and their structures were determined by spectral methods to be 4′-deacetyl griseusin A and griseusin A. The MIC values of griseusin A and 4′-deacetyl griseusin A against MRSA and E. coli were ≤ 1.0 μg/mL. The cytotoxicities of the EtOAc extract and 4′-deacetyl griseusin A were also evaluated against two cancer cell lines (human servical cancer: HeLa; murine fibroblastic cells: L-929). The EtOAc extract showed strong cytotoxic activity against HeLa and L-929 lines with IC 50 values of 1.57 and 2.43 μg/mL, respectively, whereas 4′-deacetyl griseusin A was very potent with IC 50 values of 0.43 versus HeLa, and 0.12 μg/mL against L-929. The active strain M-33-5 was identified as Streptomyces griseus by 16SrDNA sequence data.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.