- Nematocidal activity of turmeric: Synergistic action of curuminoids
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A new curcuminoid, cyclocurcumin (IV), was isolated from the nematocidally active fraction of turmeric, the rhizome of Curcuma longa, together with three known curcuminoids, curcumin (I), demethoxycurcumin (II) and bisdemethoxycurcumin (III). The structur
- Kiuchi,Goto,Sugimoto,Akao,Kondo,Tsuda
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- An insight into cyclocurcumin cis–trans isomerization: Kinetics in solution and in the presence of silver nanoparticles
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Cyclocurcumin (CyCUR) is a non-diarylheptanoid curcuminoid characterized by an α,β-unsaturated dihydropyranone moiety generally existing as trans isomer in the ground state but able to convert into the cis form by photoisomerization. Herein the kinetics of thermal cis–trans isomerization of cyclocurcumin was spectroscopically determined in ethanol, pure water and silver nanoparticles (AgNPs) aqueous solution. Energetic parameters were calculated by Arrhenius and Eyring plots in the temperature range 294–314 K. The presence of AgNPs increases the rate of the reaction, according to the polarizability of the environment. The solvatochromism of cyclocurcumin was also studied by using the Catalán empirical solvent parameters scale in a series of organic solvents. The bathochromic shift of CyCUR suggests that polarizability of the medium plays the major role in the investigated conditions.
- Angelini, Guido,Gansmüller, Axel,Pécourneau, Jérémy,Gasbarri, Carla
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- The effectiveness of natural diarylheptanoids against Trypanosoma cruzi: Cytotoxicity, ultrastructural alterations and molecular modeling studies
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Curcumin (CUR) is the major constituent of the rhizomes of Curcuma longa and has been widely investigated for its chemotherapeutic properties. The well-known activity of CUR against Leishmania sp., Trypanosoma brucei and Plasmodium falciparum led us to investigate its activity against Trypanosoma cruzi. In this work, we tested the cytotoxic effects of CUR and other natural curcuminoids on different forms of T. cruzi, as well as the ultrastructural changes induced in epimastigote form of the parasite. CUR was verified as the curcuminoid with more significant trypanocidal properties (IC50 10.13 μM on epimastigotes). Demethoxycurcumin (DMC) was equipotent to CUR (IC50 11.07 μM), but bisdemethoxycurcumin (BDMC) was less active (IC50 45.33 μM) and cyclocurcumin (CC) was inactive. In the experiment with infected murine peritoneal macrophages all diarylheptanoids were more active than the control in the inhibition of the trypomastigotes release. The electron microscopy images showed ultrastructural changes associated with the cytoskeleton of the parasite, indicating tubulin as possible target of CUR in T. cruzi. The results obtained by flow cytometry analysis of DNA content of the parasites treated with natural curcuminoids suggested a mechanism of action on microtubules related to the paclitaxel's mode of action. To better understand the mechanism of action highlighted by electron microscopy and flow cytometry experiments we performed the molecular docking of natural curcuminoids on tubulin of T. cruzi in a homology model and the results obtained showed that the observed interactions are in accordance with the IC50 values found, since there CUR and DMC perform similar interactions at the binding site on tubulin while BDMC do not realize a hydrogen bond with Lys163 residue due to the absence of methoxyl groups. These results indicate that trypanocidal properties of CUR may be related to the cytoskeletal alterations.
- Sueth-Santiago, Vitor,De Moraes, Jullianede B. B.,Alves, Eliomara Sousa Sobral,Vannier-Santos, Marcos Andre,Freire-De-lima, Celio G.,Castro, Rosane N.,Mendes-Silva, Gustavo Peron,De Nigris Del Cistia, Catarina,Magalh?es, Luma Godoy,Andricopulo, Adriano Defini,Santánna, Carlos Mauricio R.,Decote-Ricardo, Debora,Edilsonfreiredelima, Marco
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