betadex and 4-hydroxyphenylethanol

The extraction of phenolic compounds from olive mill wastes is important, not only to avoid environmental damages, but also because of the intrinsic value of those biophenols, well-known for their high antioxidant potential and health benefits. This study focuses on tyrosol (Tyr) and hydroxytyrosol (HT), two of the main phenolic compounds found in olive mill wastes. A new, simple, and eco-friendly extraction process for the removal of phenolic compounds from aqueous solutions using native β-cyclodextrin (β-CD) in the solid state has been developed. Several β-CD/biophenol molar ratios and biophenol concentrations were investigated, in order to maintain β-CD mostly in the solid state while optimizing the extraction yield and the loading capacity of the sorbent. The extraction efficiencies of Tyr and HT were up to 61%, with a total solid recovery higher than 90% using an initial concentration of 100 mM biophenol and 10 molar equivalents of β-CD. The photochemical stability of the complexes thus obtained was estimated from ∆E*ab curve vs. illumination time. The results obtained showed that the phenols encapsulated into solid β-CD are protected against photodegradation. The powder obtained could be directly developed as a safe-grade food supplement. This simple eco-friendly process could be used for extracting valuable biophenols from olive mill wastewater.

Topics: Antioxidants; beta-Cyclodextrins; Dietary Supplements; Olea; Olive Oil; Phenylethyl Alcohol; Plant Extracts; Wastewater

Olives and olive oil, a key food type of the Mediterranean diets, are packed with various important polyphenols including oleuropein (OLE), hydroxytyrosol (HTY) and tyrosol (TYR). OLE and HTY are highly powerful antioxidants and play a prime role in the therapeutics of free radical-related diseases. Their molecular stabilities and antioxidant properties can be improved by cyclodextrin (CD) encapsulation. Here, we present a systematic investigation on the inclusion complexes of β-CD-TYR (1), β-CD-HTY (2) and β-CD-OLE (3) by combined single-crystal structure determination, DFT complete-geometry optimization and DPPH antioxidant assay. X-ray analysis and DFT calculation reveal the preference of inclusion geometry with deep protrusion of the aromatic ring moieties of TYR, HTY and OLE from the β-CD O6-H-side, and the common host-guest stabilization scheme via intermolecular O-H⋯O hydrogen bonding interactions. No polyphenol OH group is shielded in the β-CD cavity, in contrast to the structures of β-CD-tea catechins complexes. The established host-guest O-H⋯O hydrogen bonds help to elevate antioxidant capacities of the olive polyphenols upon β-CD encapsulation. The order of antioxidant activity 2 >3 ≫ 1 based on the DPPH measurement is in fair agreement with their relative thermodynamic stabilities derived from DFT calculation.

Topics: beta-Cyclodextrins; Crystallography, X-Ray; Free Radical Scavengers; Hydrogen Bonding; Iridoid Glucosides; Iridoids; Models, Chemical; Molecular Structure; Phenylethyl Alcohol; Quantum Theory; Structure-Activity Relationship; Thermodynamics

Alperujo-a two-phase olive mill waste that is composed of olive vegetation water and solid skin, pulp, and seed fragments - is a highly valuable olive by-product due to its high content in phenolic compounds. In this study, we assessed whether β-cyclodextrin (β-CD), which is used to extract and protect alpejuro phenolic compounds (hydroxytyrosol-

Topics: Antioxidants; beta-Cyclodextrins; Biological Availability; Caco-2 Cells; Caffeic Acids; Coumaric Acids; Glucosides; Humans; Olea; Phenols; Phenylethyl Alcohol; Plant Extracts; Propionates

Tyrosol and caffeic acid are biophenols that contribute to the beneficial properties of virgin olive oil. The influence of hydroxypropyl-β-cyclodextrin (HPβ-CD) on their respective antioxidant capacities was analyzed. The ORAC antioxidant activity of tyrosol (expressed as μM Trolox equivalents/μM Tyrosol) was 0.83 ± 0.03 and it increased up to 1.20 ± 0.11 in the presence of 0.8 mM HPβ-CD. However, the ORAC antioxidant activity of caffeic acid experienced no change. The different effect of HPβ-CD on each compound was discussed. In addition, the effect of increasing concentrations of different cyclodextrins in the development of ORAC-fluorescence (ORAC-FL) assays was studied. The ORAC signal was higher for HPβ-CD, followed by Mβ-CD, β-CD, γ-CD and finally α-CD. These results could be explained by the formation of inclusion complexes with fluorescein.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Antioxidants; beta-Cyclodextrins; Caffeic Acids; Cyclodextrins; Phenylethyl Alcohol; Spectrometry, Fluorescence