curcumin and hydroxide-ion

Applying hydrophilic coatings on polymeric nanofibers combined with layered double hydroxide (LDH) not only enhances the efficiency of drug delivery systems but also increases cell adhesion. This work aimed to prepare poly(vinyl alcohol)/sodium alginate (PVA/SA) (2/1)-coated poly(lactic acid) (PLA) nanofibers containing curcumin-loaded layered double hydroxide (LDH) and to investigate their drug release and mechanical properties and their biocompatibility. The optimum PLA nanofibrous sample was considered to be that based on 3 wt% of curcumin-loaded LDH (PLA-3%LDH) with a drug encapsulation efficiency of ∼18% in which a minimum average nanofiber diameter of ∼476 nm along with a high tensile strength of 3.00 MPa were obtained. In the next step, a PVA/SA (2/1) layer was coated on the PLA-3%LDH; as a result, the hydrophilicity of the sample was improved and the elongation at break was decreased remarkably. In this regard the cell viability reached 80% for the coated PLA. Moreover, the formation of a layer of (PVA/SA) on the PLA nanofibers lowered the burst release and resulted in a more sustained drug release, which is a vital feature in dermal applications. A multiscale modeling method was applied for simulation of the mechanical properties of the composite scaffold and the results showed that this method can predict the data with 83% accuracy. The results of this study indicate that the formation of a layer of PVA/SA (2/1) has a significant effect on hydrophilicity and consequently improves cell adhesion and proliferation.

Topics: Curcumin; Hydroxides; Lactic Acid; Nanofibers; Polyesters; Polyvinyl Alcohol

A series of polyphenolic curcumin analogs were synthesized and their inhibitory effects on mushroom tyrosinase and the inhibition of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical formation were evaluated. The results indictated that the analogs possessing m-diphenols and o-diphenols exhibited more potent inhibitory activity on tyrosinase than reference compound rojic acid, and that the analogs with o-diphenols exhibited more potent inhibitory activity of DPPH free-radical formation than reference compound vitamin C. The inhibition kinetics, analyzed by Lineweaver-Burk plots, revealed that compounds B(2) and C(2) bearing o-diphenols were non-competitive inhibitors, while compounds B(11) and C(11) bearing m-diphenols were competitive inhibitors. In particular, representative compounds C(2) and B(11) showed no side effects at a dose of 2,000 mg/kg in a preliminary evaluation of acute toxicity in mice. These results suggest that such polyphenolic curcumin analogs might serve as lead compounds for further design of new potential tyrosinase inhibitors.

Topics: Agaricales; Animals; Biphenyl Compounds; Catalytic Domain; Curcumin; Drug Discovery; Enzyme Inhibitors; Female; Free Radical Scavengers; Hydroxides; Inhibitory Concentration 50; Male; Mice; Models, Molecular; Monophenol Monooxygenase; Picrates; Polyphenols

Curcumin, a known phytochemical antioxidant was found to be useful as a potential sensor for some small biologically important molecules. Hydrogen peroxide, the sodium salt of nitrite (NO2-), hydroxide (OH-), bromide (Br-) and iodide (I-) were observed to quench the fluorescence of sol-gel encapsulated curcumin, which emits radiation at 530 nm when excited at 420 nm. The observed bimolecular quenching constant which is related to the Stern-Volmer quenching constant, KSV, for the species studied in this work was determined by a modified Stern-Volmer relation for molecular surface accessibility, was observed to be specific for each of these anions and correlates quite well with their half-wave potentials, E1/2. The extent of permeability of these molecules through the pores of the sol-gel matrix was determined and they, also, correlated with these molecules' charge densities and sizes. In all the species, the reaction was quite exergonic and the free energy change, DeltaGoET, obtained in each case, suggest an outer-sphere, long range electron transfer mechanism. These observations open up the possible use of curcumin as a sensor for probing and characterizing some relevant bio-molecules in biological systems.

Topics: Biological Factors; Biosensing Techniques; Bromides; Curcumin; Drug Compounding; Fluorescent Dyes; Gels; Hydrogen Peroxide; Hydroxides; Iodine; Models, Biological; Nitrogen Dioxide; Polymethyl Methacrylate; Spectrometry, Fluorescence