83-30-7Relevant articles and documents
Catalytic evaluation of biocompatible chitosan-stabilized gold nanoparticles on oxidation of morin
Bulut, Onur,Yilmaz, M. Deniz
, (2021)
Herein, we present a study on the catalytic evaluation of biocompatible chitosan-stabilized gold nanoparticles (CH-AuNPs) on the oxidation of morin as a model reaction. Biocompatible CH-AuNPs have been characterized through several analytical methods such as TEM, UV–vis, DLS and zeta potential analyses. CH-AuNPs have a small size (10 ± 0.4 nm) with a narrow size distribution and high positive surface charge (+40.1 mV). CH-AuNPs has been demonstrated to be highly active nanocatalysts for the oxidation of morin with the assistance of H2O2 as an oxidant compared with control experiments. The oxidation reaction follows a pseudo-first-order reaction. The kinetic studies show that apparent rate constant (kapp) is positively correlated with the concentrations of CH-AuNPs and H2O2, while it is negatively correlated with morin concentration. Furthermore, the reusability tests have been performed and the results demonstrate the long-term stability and reusability of CH-AuNPs without any loss of catalytic activity. Cytotoxicity studies exhibit that CH-AuNPs have low toxicity and they are biocompatible with HeLa and MCF-7 cells.
Effect of alkali and alkaline earth metal dopants on catalytic activity of mesoporous cobalt oxide evaluated using a model reaction
Bingwa, Ndzondelelo,Bewana, Semakaleng,Ndolomingo, Matumuene Joe,Mawila, Naphtaly,Mogudi, Batsile,Ncube, Phendukani,Carleschi, Emanuela,Doyle, Bryan P.,Haumann, Marco,Meijboom, Reinout
, p. 189 - 195 (2018)
Herein we report the synthesis of mesoporous cobalt oxides in pure (Co3O4) and alkali and alkaline earth metal doped form (Li-, Ca-, Cs-, and Na-, K-, and Mg/Co3O4) via the inverse micelle method. The as-prepared materials were characterized by powder X-ray diffraction (pXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), nitrogen sorption (BET), hydrogen-temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). Characterization results suggested that the as-synthesized materials are of amorphous and mesoporous nature. Their catalytic activity was investigated using a model reaction, namely the liquid-phase morin oxidation. Results revealed pure cobalt oxide to be the better catalyst compared to its doped counterparts. The stability of Li/Co3O4 material was investigated exemplarily by recycling and reusing the catalysts for as many as four catalytic cycles. Conversion of morin was complete in all runs and no significant metal leaching could be detected by the use of inductively coupled plasma mass spectrometry (ICP-MS).
Exploring the oxidation and iron binding profile of a cyclodextrin encapsulated quercetin complex unveiled a controlled complex dissociation through a chemical stimulus
Diamantis, Dimitrios A.,Ramesova, Sarka,Chatzigiannis, Christos M.,Degano, Ilaria,Gerogianni, Paraskevi S.,Karadima, Konstantina E.,Perikleous, Sonia,Rekkas, Dimitrios,Gerothanassis, Ioannis P.,Galaris, Dimitrios,Mavromoustakos, Thomas,Valsami, Georgia,Sokolova, Romana,Tzakos, Andreas G.
, p. 1913 - 1924 (2018/07/03)
Background: Flavonoids possess a rich polypharmacological profile and their biological role is linked to their oxidation state protecting DNA from oxidative stress damage. However, their bioavailability is hampered due to their poor aqueous solubility. This can be surpassed through encapsulation to supramolecular carriers as cyclodextrin (CD). A quercetin- 2HP-β-CD complex has been formerly reported by us. However, once the flavonoid is in its 2HP-β-CD encapsulated state its oxidation potential, its decomplexation mechanism, its potential to protect DNA damage from oxidative stress remained elusive. To unveil this, an array of biophysical techniques was used. Methods: The quercetin-2HP-β-CD complex was evaluated through solubility and dissolution experiments, electrochemical and spectroelectrochemical studies (Cyclic Voltammetry), UV–Vis spectroscopy, HPLC-ESI-MS/MS and HPLC-DAD, fluorescence spectroscopy, NMR Spectroscopy, theoretical calculations (density functional theory (DFT)) and biological evaluation of the protection offered against H2O2-induced DNA damage. Results: Encapsulation of quercetin inside the supramolecule's cavity enhanced its solubility and retained its oxidation profile. Although the protective ability of the quercetin-2HP-β-CD complex against H2O2 was diminished, iron serves as a chemical stimulus to dissociate the complex and release quercetin. Conclusions: We found that in a quercetin-2HP-β-CD inclusion complex quercetin retains its oxidation profile similarly to its native state, while iron can operate as a chemical stimulus to release quercetin from its host cavity. General significance: The oxidation profile of a natural product once it is encapsulated in a supramolecular carrier was unveiled as also it was discovered that decomplexation can be triggered by a chemical stimilus.
