betadex and myricetin

The application of macrocyclic hosts for construction of different electrochemical devices and separation matrices has attracted much attentions due to their benign biocompatibility and simplicity of synthesis. Myricetin and rutin are considered two of the most bioactive flavonoids, which have been proved to exhibit various physiological functions. This work reports a simple and facile approach for the synthesis of β-cyclodextrin-gold@3, 4, 9, 10-perylene tetracarboxylic acid functionalized single-walled carbon nanohorns (β-CD-Au@PTCA-SWCNHs) nanohybrids. The simultaneous electrochemical determination of myricetin and rutin using a β-CD-Au@PTCA-SWCNHs-modified glassy carbon electrode was established. The results show that the β-CD-Au@PTCA-SWCNHs-modified electrode displayed electrochemical signal superior to those of Au@PTCA-;SWCNHs and SWCNHs towards myricetin and rutin. The proposed modified electrode has a linear response range of 0.01-10.00 μM both for myricetin and rutin with relatively low detection limits of 0.0038 μM for myricetin and 0.0044 μM (S/N = 3) for rutin, respectively. The excellent performance of the sensing platform is considered to be the synergic effects of the SWCNHs (e.g. their good electrochemical properties and large surface area) and β-CD (e.g. a hydrophilic external surface, a high supramolecular recognition, and a good enrichment capability).

Topics: beta-Cyclodextrins; Electrochemical Techniques; Electrodes; Flavonoids; Gold; Humans; Hydrogen-Ion Concentration; Nanotubes, Carbon; Perylene; Rutin

Myricetin, a bioactive plant flavonol, readily forms inclusion complex with the drug delivery vehicle beta-cyclodextrin (β-CD). Appearance of typical "dual emission", consisting of normal (470 nm) and ESIPT tautomer (530 nm) bands, with concomitant rise in fluorescence intensity and dramatically blue shifted normal fluorescence of myricetin with increasing β-CD concentration, indicates facile entry of myricetin into the cavity of β-CD. The stoichiometry of the inclusion complex has been established to be equimolar (1:1), with an equilibrium constant of 439 ± 18 M(-1) at 25 °C. The driving force of inclusion is attributed to strong van der Waals interaction and formation of hydrogen bond between host (β-CD) and guest (myricetin). Both experimental and theoretical studies indicate that myricetin possibly incorporates within β-CD through its benzoyl moiety. Inclusion in β-CD increases the antioxidant potency of myricetin which has been attributed to the less delocalised HOMO and reduced HOMO-LUMO energy gap in the confined state.

Topics: beta-Cyclodextrins; Biphenyl Compounds; Circular Dichroism; Drug Carriers; Flavonoids; Hydrogen Bonding; Kinetics; Models, Molecular; Molecular Docking Simulation; Molecular Structure; Picrates; Quantum Theory; Solubility; Spectrometry, Fluorescence; Thermodynamics

Myricetin shows low oral bioavailability (<10%) in rats due to poor aqueous solubility, though it has various pharmacological activities. Complexation with cyclodextrins (CDs) is a potent pharmaceutical method to enhance the bioavailability of poorly soluble compounds. The myricetin/HP-β-CD inclusion complex was prepared and confirmed by DSC, PXRD, and SEM. Here, the inclusion mode is described in detail with regard to structural and energetic aspects using a phase solubility diagram and 1H NMR, NOESY, and FT-IR spectra. The water solubility and dissolution rate of myricetin were greatly enhanced by forming the myricetin/HP-β-CD inclusion complex. Consequently, the oral bioavailability of the myricetin/HP-β-CD inclusion complex in rats was effectively increased 9.4-fold over free myricetin, and its antioxidant activity was also improved. The present study provides useful information for the potential application of complexation with myricetin, a naturally occurring hydrophobic phenolic compound in herbal medicine.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Administration, Oral; Animals; Antioxidants; beta-Cyclodextrins; Biological Availability; Biphenyl Compounds; Drug Carriers; Flavonoids; Male; Picrates; Rats; Rats, Sprague-Dawley; Solubility