CHARACTERIZATION STUDIES ON A TETRAHYDROCURCUMIN-ZINC COMPLEX

Objective: Preparation and characterization studies on tetrahydrocurcumin complexed with zinc, with particular reference to the location of zinc in the complex. Methods: Structural characteristics of tetrahydrocurcumin and its complex with zinc were compared using elemental analysis, mass spectrometry (MS), proton, and carbon-13 nuclear magnetic resonance spectroscopy (NMR), ultraviolet-visible (UV) absorption spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. Results: MS data indicates a Zn molecule holds two THCur components together. NMR data provide evidence that the zinc ion is associated with the 1,3-diketone part of the linker region of the associated THCur. FTIR data is consistent with zinc interaction with the enol tautomer of the 1,3-diketone at the center of the linker region of THCur. UV data indicate that a zinc-dependent shift in absorbance maximum is consistent with changes in the structure of THCur resulting from complexation with zinc. Together, this data indicates the complexation of zinc with tetrahydrocurcumin is consistent with zinc linking two molecules of tetrahydrocurcumin together by binding to the enol forms of the 1,3-diketone moieties located in the linker regions between the aromatic rings. Conclusion: The spectral properties of the tetrahydrocurcumin-zinc complex are consistent with a structure in which zinc is encased in two tetrahydrocurcumin moieties. Additional studies are needed to determine if this structure results in altered bioavailability, antioxidant activity and other properties important for pharmaceutical development

Prediction of anti-Alzheimer’s activity of flavonoids targeting acetylcholinesterase in silico

Introduction – Prenylated and pyrano-flavonoids of the genus Artocarpus J. R. Forster & G. Forster are well known for their acetylcholinesterase (AchE) inhibitory, anticholinergic, antiinflammatory, antimicrobial, antioxidant, antiproliferative and tyrosinase inhibitory activities. Some of these compounds have also been shown to be effective against Alzheimer’s disease. Objective – The aim of the in silico study was to establish protocols to predict the most effective flavonoid from prenylated and pyrano-flavonoid classes for AchE inhibition linking to the potential treatment of Alzheimer’s disease. Methodology – Three flavonoids isolated from Artocarpus anisophyllus Miq. were selected for the study. With these compounds, Lipinski filter, ADME/Tox screening, molecular docking and QSAR were performed in silico. In vitro activity was evaluated by bioactivity staining based on the Ellman’s method. Results – In the Lipinski filter and ADME/Tox screening, all test compounds produced positive results, but in the target fishing, only one flavonoid could successfully target AchE. Molecular docking was performed on this flavonoid, and this compound gained the score as -13.5762. From the QSAR analysis the IC50 was found to be 1659.59 nM. Again, 100 derivatives were generated from the parent compound and docking was performed. The derivative number 20 was the best scorer i.e., -31.6392 and IC50 was predicted as 6.025 nM. Conclusion – Results indicated that flavonoids could be efficient inhibitors of AchE and thus, could be useful in the management of Alzheimer’s disease