- 5-Substituted isatin thiosemicarbazones as inhibitors of tyrosinase: Insights of substituent effects
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Seven isatin-thiosemicarbazone analogues bearing different substituents (R) attached at C-5 of the indoline ring, TSC-ISA-R (R = -H, -CH3, -OCH3, -OCF3, -F, -Cl and -NO2), were synthesized and evaluated as inhibitors of mushroom tyrosinase (TYR). The inhibitory behaviour and performance of TSC-ISA-R were investigated spectroscopically in relation to the substituent modifications through examining their inhibition against the diphenolase activity of TYR using L-DOPA as a substrate. The IC50 values of TSC-ISA-R were determined to be in the range of 81–209 μM. The kinetic analysis showed that TSC-ISA-R were reversible and mixed type inhibitors. Three potential non-covalent interactions rather than complexation including the binding of TSC-ISA-R with free TYR, TYR-L-DOPA complex, and with substrate L-DOPA were found to be involved in the inhibition. The substituent modifications affected these interactions by varying the characters of the resulting TSC-ISA-R in different degrees. The thiosemicarbazido moiety of each TSC-ISA-R contributed predominantly to the inhibition, and the isatin moiety seemed to play a regulatory role in the binding of TSC-ISA-R to the target molecules. The results of theoretical calculations using density functional theory method indicated a different effect of –R on the electron distribution in HOMO of TSC-ISA-R. The LUMO-HOMO energy gap of TSC-ISA-R almost accords with the trend of their experimental inhibition potency.
- Cheng, Run,Shi, Wenyan,Yuan, Qingyun,Tang, Ruiren,Wang, Yujie,Yang, Di,Xiao, Xin,Zeng, Jianping,Chen, Jingwen,Wang, Yanqing
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- A series of α-heterocyclic carboxaldehyde thiosemicarbazones inhibit topoisomerase IIα catalytic activity
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A series of novel thiosemicarbazone derivatives bearing condensed heterocyclic carboxaldehyde moieties were designed and synthesized. Among them, TSC24 exhibited broad antiproliferative activity in a panel of human tumor cells and suppressed tumor growth in mice. The mechanism research revealed that TSC24 was not only an iron chelator but also a topoisomerase IIα catalytic inhibitor. Its inhibition on topoisomerase IIα was due to direct interaction with the ATPase domain of topoisomerase IIα which led to the block of ATP hydrolysis. Molecular docking predicted that TSC24 might bind at the ATP binding site, which was confirmed by the competitive inhibition assay. These results about the mechanisms involved in the anticancer activities of thiosemicarbazones will aid in the rational design of novel topoisomerase II-targeted drugs and will provide insights into the discovery and development of novel cancer therapeutics based on the dual activity to chelate iron and to inhibit the catalytic activity of topoisomerase IIα.
- Huang, He,Chen, Qin,Ku, Xin,Meng, Linghua,Lin, Liping,Wang, Xiang,Zhu, Caihua,Wang, Yi,Chen, Zhi,Li, Ming,Jiang, Hualiang,Chen, Kaixian,Ding, Jian,Liu, Hong
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experimental part
p. 3048 - 3064
(2010/09/05)
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- Synthesis, characterization and spectral evaluation of some new substituted thiosemicarbazides and thiosemicarbazones
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A new series of substituted thiosemicarbazides and substituted thiosemicarbazones containing different functional groups, thiosemicarbazones have been synthesized by the condensation reaction between newly synthesized substituted thiosemicarbazides with s
- Pareek, Alok K.,Joseph,Seth, Daya S.
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experimental part
p. 1549 - 1552
(2011/10/12)
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- 2-Methoxy-5-methylphenyl thiosemicarbazide: A versatile molecule for the synthesis of thiadiazoles and imidazolinones possessing multiple biological activities
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Thiosemicarbazide 1 has been prepared by the reaction of 2-methoxy-5-methyl aniline, ammonia and carbon disulphide with ethanol (95%) and sodium chloroacetate, followed by addition of hydrazine hydrate, which on cyclisation with different aromatic carboxylic acids and substituted azlactones in pyridine furnish the corresponding 2-aryl-5-(2′-methoxy-5′-methylphenyl amino)-1,3,4-thiadiazoles 2a-o and 2-phenyl-4-arylidene-1-(2′-methoxy-5′-methylphenyl thiourido)-5-oxo-imidazolines 3a-o. All the compounds have been characterised by elemental analyses, IR, 1H NMR and Mass spectral data. All the compounds have been evaluated in vitro for their antimicrobial activity against several microbes and antitubercular activity against Mycobacterium tuberculosis H37Rv and anticancer activity. Two compounds are found to be active in anticancer assay.
- Hirpara,Parikh,Merja,Parekh
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p. 1172 - 1175
(2007/10/03)
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