- Novel synthesised flavone derivatives provide significant insight into the structural features required for enhanced anti-proliferative activity
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With many cancers showing resistance to current chemotherapies, the search for novel anti-cancer agents is attracting considerable attention. Natural flavonoids have been identified as useful leads in such programmes. However, since an in-depth understanding of the structural requirements for optimum activity is generally lacking, further research is required before the full potential of flavonoids as anti-proliferative agents can be realised. Herein a broad library of 76 methoxy and hydroxy flavones, and their 4-thio analogues, was constructed and their structure-activity relationships for anti-proliferative activity against the breast cancer cell lines MCF-7 (ER +ve), MCF-7/DX (ER +ve, anthracycline resistant) and MDA-MB-231 (ER -ve) were probed. Within this library, 42 compounds were novel, and all compounds were afforded in good yields and >95% purity. The most promising lead compounds, specifically the novel hydroxy 4-thioflavones 15f and 16f, were further evaluated for their anti-proliferative activities against a broader range of cancer cell lines by the National Cancer Institute (NCI), USA and displayed significant growth inhibition profiles (e.g. compound-15f: MCF-7 (GI50 = 0.18 μM), T-47D (GI50 = 0.03 μM) and MDA-MB-468 (GI50 = 0.47 μM) and compound-16f: MCF-7 (GI50 = 1.46 μM), T-47D (GI50 = 1.27 μM) and MDA-MB-231 (GI50 = 1.81 μM)). Overall, 15f and 16f exhibited 7-46 fold greater anti-proliferative potency than the natural flavone chrysin (2d). A systematic structure-activity relationship study against the breast cancer cell lines highlighted that free hydroxyl groups and the B-ring phenyl groups were essential for enhanced anti-proliferative activities. Substitution of the 4-CO functionality with a 4-CS functionality, and incorporation of electron withdrawing groups at C-4′ of the B-ring phenyl, also enhanced activity. Molecular docking and mechanistic studies suggest that the anti-proliferative effects of flavones 15f and 16f are mediated via ER-independent cleavage of PARP and downregulation of GSK-3β for MCF-7 and MCF-7/DX cell lines. For the MDA-MB-231 cell line, restoration of the wild-type p53 DNA binding activity of mutant p53 tumour suppressor gene was indicated.
- Ravishankar, Divyashree,Watson, Kimberly A.,Greco, Francesca,Osborn, Helen M. I.
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p. 64544 - 64556
(2016/07/21)
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- Preparation having antioxidant properties
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The invention relates to a preparation having antioxidant properties, comprising at least one compound of the formula I where R1 to R10 may be identical or different and are selected from H, OR11, straight-chain or branched C1- to C20-alkyl groups, straight-chain or branched C3- to C20-alkenyl groups, straight-chain or branched C1- to C20-hydroxyalkyl groups, where the hydroxyl group may be bonded to a primary or secondary carbon atom of the chain and furthermore the alkyl chain may also be interrupted by oxygen, and/or C3- to C10-cycloalkyl groups and/or C3- to C12-cycloalkenyl groups, where the rings may each also be bridged by —(CH2)n— groups, where n=1 to 3, where all OR11 are, independently of one another, OH, C1- to C20-alkoxy groups, C3- to C20-alkenyloxy groups, straight-chain or branched C1- to C20-hydroxyalkoxy groups and/or C3- to C10-cycloalkoxy groups and/or C3- to C12-cycloalkenyloxy groups, where the rings may each also be bridged by —(CH2)n— groups, where n=1 to 3, and/or mono- and/or oligoglycosyl radicals, with the proviso that at least 3 radicals from R1 to R7 are OH and that at least 2 pairs of adjacent —OH groups are present in the molecule, or R2, R5 and R6 are OH and the radicals R1, R3, R4 and R7-10 are H.
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