Preparation of gallic acid-hydroxypropyl-β-cyclodextrin inclusion compound and study on its effect mechanism on Escherichia coli in vitro

The purpose of this paper is to optimize the preparation process of gallic acid-hydroxypropyl-β-cyclodextrin inclusion compound and to study its antibacterial effect in vitro. Orthogonal test was used to screen the preparation method of the compound. The microscopic appearance of the compound was observed by microscope, and the solubility of the compound was detected by the dissolution method. The antibacterial activity of the compound was measured by the Oxford cup method. Under the transmission electron microscope, the microstructure of the cells and the intracellular ultrastructure changes were observed. The results showed that when the molar ratio of gallic acid and hydroxypropyl-β-cyclodextrin inclusion was 1:1, the ethanol concentration was 80%, the inclusion temperature was 30 °C, and the inclusion time was 0.5 h, the inclusion effect was the best with an inclusion rate of 99.45%; the solubility of gallic acid before the inclusion was (6.515 ±0.55) mg/mL, while after the inclusion, the solubility increased by more than 100 times to (710.048 ±1.08) mg/mL; gallic acid-hydroxypropyl-β-cyclodextrin inclusion compound could dissolve and destroy the cell membrane of Escherichia coli. The preparation process of gallic acid-hydroxypropyl-β-cyclodextrin inclusion compound was stable and feasible, and there was a good inclusion effect. After the inclusion, the solubility of gallic acid increased significantly; the prepared inclusion compound could inhibit the gram-negative bacteria Escherichia coli by destroying the integrity of the bacterial cell membrane, which could provide data support for the application and development of gallic acid.

Solid γ-Cyclodextrin Inclusion Compound with Gingerols, a Multi-Component Guest: Preparation, Properties and Application in Yogurt

Gingerols from the rhizome of fresh ginger (Zingiber officinale) were obtained by a simple extraction, followed by purification. The gingerols extract was composed of 6-gingerol (54%), 8-gingerol (20%), and 10-gingerol (26%). It was included into γ-cyclodextrin by classic co-dissolution procedures. Solid-state characterisation of γ-cyclodextrin·gingerols shows that this inclusion compound features 1:1 host-to-guest stoichiometry and that it is a microcrystalline powder with a crystalline cell that belongs to the tetragonal space group 4212, having the host molecules stacked in infinite channels where the gingerols are accommodated. In chimico studies with ABTS•+ scavenging, NO• scavenging, β-carotene peroxidation, and 5-LOX inhibition show that γ-cyclodextrin is a suitable carrier for gingerols, because it does not alter their reactivity towards these substances. Yogurt was tested as a matrix for the incorporation of gingerols and γ-cyclodextrin·gingerols into foodstuff. The colour of the fortified yogurt suffered little alterations. In the case of yogurt with the inclusion compound, γ-cyclodextrin·gingerols, as fortificant, these alterations were not perceptible to the naked eye. Moreover, yogurt with γ-cyclodextrin·gingerols showed a good antioxidant activity, thus being suitable for use in nutraceutical applications.

Advance on the nano delivery system of curcumin

Curcumin has various physiological functions such as anti-oxidation, anti-cancer and prevention of Alzheimer's disease, but its poor water solubility and unstable physicochemical property limits the development and application of curcumin. The nano delivery carriers for curcumin prepared by nanotechnology can effectively solve these problems above. This paper summarized the research reports and literatures at home and abroad in recent years, categorized the nanocarriers of curcumin and analysed the definitions, preparation methods, properties and features, advantages and disadvantages of nano-emulsion, solid lipid particles, liposome, cyclodextrin inclusion compound respectively. In addition, this paper predicted application prospects of curcumin in the fields of food and medicine and provided references for the comprehensive development and utilization of curcumin.