An inclusion complex of eugenol into β-cyclodextrin: Preparation, and physicochemical and antifungal characterization

Enhancement in Antibacterial Activities of Eugenol-Entrapped Ethosome Nanoparticles via Strengthening Its Permeability and Sustained Release

The antibacterial efficiency and synergistic mechanisms of novel formulated eugenol entrapped ethosome nanoparticles (ELG-NPs) against fruit anthracnose were investigated. The results showed that concentrations of eugenol and ethanol significantly influenced the particle size and entrapment efficiency of nanoethosome, and the particle size significantly influenced the antibacterial effect. Superior ELG-NPs with optimized process (0.5% eugenol, 2% lecithin, and 30% ethanol) were obtained with a size of 44.21 nm and entrapment efficiency of 82%. ELG-NPs exhibited an antibacterial activity (>93%) against fruit pathogens that was greater than that of free eugenol and showed 100% inhibition of the anthracnose incidence in postharvest loquat after 6 d. The permeability study, first visualized in banana cortex with fluorescent indicators, demonstrated that eugenol delivered to the interior with ELG-NPs was 6-fold higher than that of free eugenol. ELG-NPs showed a satisfactory slow-release and prolonged antibacterial action. This work provides a promising strategy for disease controls in agricultural, food, cosmetic, and medical areas.

Impact of Gelatin Supplemented with Gum Arabic, Tween 20, and β-Cyclodextrin on the Microencapsulation of Turkish Oregano Extract

Microencapsulation protects core materials from deteriorating due to environmental conditions, such as moisture or oxidation, and improves the bioavailability of active compounds, allowing one to make solid formulations from oils and increase their solubility. Wall and core material properties determine the microencapsulation efficiency and the best results are achieved when a wall material mixture is used to prepare the microcapsules. In this work, we optimized the wall material composition (gelatin supplemented with gum Arabic, Tween 20, and β-cyclodextrin) of Turkish oregano microcapsules prepared by spray-drying technology to increase the product yield, the encapsulation efficiency, and to achieve narrower particle size distribution. When the wall material solution contained 10 g of gelatin, 7.5 g of gum Arabic, 1.99 g of Tween 20, 1.98 g of β-cyclodextrin, and 20 g of ethanolic oregano extract, the encapsulation efficiency of oregano's active compounds, rosmarinic acid and carvacrol, were 96.7% and 99.8%, respectively, and the product yield was 85.63%. The physicochemical properties, microscopic morphology, and in vitro release of the prepared microcapsules were characterized in the study. The use of gelatin as the main coating material, in supplementation with gum Arabic, Tween 20, and β-cyclodextrin, not only improved the encapsulation efficiency, but also increased the in vitro release of both main active compounds of Turkish oregano extract-rosmarinic acid and carvacrol.

Effect of Selective Encapsulation of Hydroxypropyl-β-cyclodextrin on Components and Antibacterial Properties of Star Anise Essential Oil

Star anise essential oil (SAEO) is a plant essential oil with good antibacterial activity, but its applications are limited due to its high volatility, strong smell, and unstable physical and chemical properties. The effect of selective encapsulation of SAEO by hydroxypropyl-β-cyclodextrin (HPCD) on its compositions, volatility stability and antibacterial activity was investigated. The GC-MS results indicated that the compositions reduced and content of the compositions of SAEO changed after encapsulation. Most of the components in SAEO were successfully encapsulated by HPCD, which can be supported by data from FTIR and ¹H NMR. According to the molecular modeling results, the three guest molecules (trans-anethole, estragole and trans-foeniculin) were all docked in the cavity of HPCD on the isoallyl (or allyl) side. The volatile stability of SAEO before and after encapsulation was evaluated by electronic nose, and the results confirmed that encapsulation significantly reduced the irritating smell of SAEO and makes the clathrate have a sustained release effect. Furthermore, in the antibacterial test, the selective encapsulation of HPCD improved the inhibition effect of SAEO on Rhizopus stolonoifer, Saccharomyces cerevisiae, and E. coli and its antibacterial stability in 24 h.

The inclusion complex of oxyresveratrol in modified cyclodextrins: A thermodynamic, structural, physicochemical, fluorescent and computational study

The interaction between oxyresveratrol (a type of stilbene with high biological activity) and modified cyclodextrins (CDs) was studied. Using HPLC-RP, was seen to form a 1:1 complex with all the CDs tested. The best CD in this respect was MβCD (K_F=606.65±30.18M^-1), the complexation showing a strong dependence on pH and temperature: The complexation constant (K_F) decreased as the pH and temperature increased. The thermodynamic parameters studied (ΔH°, ΔS° and ΔG°) showed negative entropy, enthalpy and Gibbs free energy change at 25°C. In addition, fluorescence signal of oxyresveratrol increased when MβCD was added. The oxyresveratrol emission and excitation spectra were obtained for first time. A ¹H NMR was carried out to study the structure of the complex and, DSC studied demonstrated the complexation. A computational study by molecular docking was made to complement the structural study.

Novel synthesized 2, 4-DAPG analogues: antifungal activity, mechanism and toxicology

2, 4-Diacetylphloroglucinol (2,4-DAPG), a natural phenolic compound, has been investigated in light of its biological activities against plant pathogens. To improve its potential application, fourteen 2,4-DAPG analogous were synthesized through the Friedel-Crafts reaction using acyl chlorides and phloroglucinol. Of the 2,4-DAPG derivatives, MP4 exhibited much higher antifungal activity against Penicillium digitatum and P. italicum, the major pathogenic fungi in citrus fruit, than 2, 4-DAPG in vitro, and significantly inhibited the development of decay in harvested mandarin (Citrus reticulata Blanco cv. Shatang.) fruit in vivo. It was found that MP4 resulted in the wrinkle of the hyphae in both fungi with serious folds and breakage. In addition, the expression of several cytochrome P450 (CYP) genes were also modified in both fungi by MP4, which might be associated with the disorder of cell membrane formation. Furthermore, the toxicology of MP4 by evaluating the cell proliferation effect on human normal lung epithelial (16HBE) and kidney 293 (HEK293) cells, was significantly lower than that of albesilate, a widely used fungicide in harvested citrus fruit. In summary, the synthesized MP4 has shown a great potential as a novel fungicide that might be useful for control of postharvest decay in citrus fruit.