Anna Buonocore

Non-covalent inclusion of ferulic acid with α-cyclodextrin improves photo-stability and delivery: NMR and modeling studies

Ferulic acid (FA) is a highly effective antioxidant and photo-protective agent, already approved in Japan as a sunscreen, but it is poorly suited for cosmetic application because of its low physicochemical stability. We prepared the inclusion complex of FA with alpha-cyclodextrin by co-precipitation from an aqueous solution, and used (1)H NMR and molecular dynamics to investigate the most probable structure of the inclusion complex. In rotating frame nuclear Overhouser effect spectroscopy (ROESY) experiments FA penetrated the alpha-CD hydrophobic cavity with the alpha,beta-unsaturated part of the molecule and some of its aromatic skeleton. In proton chemical shift measurements of FA and alpha-cyclodextrins we determined the stoichiometry of the association complex (1:1) by Jobs method, and its stability constant (K(1:1) 1162+/-140 M(-1)) and described the molecular dynamics of the complex on the basis of theoretical studies. Encapsulation with alpha-cyclodextrin improves (i) the chemical stability of FA against UVB stress (10 MED [Minimal Erythemal Dose: 1 MED=25 mJ/cm(2) for skin phototype II: 30]), since no degradation products are formed after irradiation, and (ii) the bioavailability of FA on the skin, slowing its delivery (Strainer cell model).

New microencapsulated sunscreens: technology and comparative evaluation

The aim of this work is to obtain new technologically improved microencapsulated sunscreens characterised by UV-radiation stability, good substantivity, low toxicity, a better tolerability and easiness to formulation. For this purpose we prepared two different systems using semisynthetic Hyaluronic Acid (HA) benzyl ester and a synthetic polymer (patent pending). We obtained these systems using two different methodologies: emulsification/solvent evaporation and emulsification/solvent extraction. The comparison between the two formulated systems was carried out in terms of their chemical-physical and biological properties.

The human olfactory receptor 17-40

To gain structural insight on the interactions between odorants and the human olfactory receptor, we did homology modelling of the receptor structure, followed by molecular docking simulation with ligands. Molecular dynamics simulation on the structures resulting from docking served to estimate the binding free energy of the various odorant families. A correlation with the odorous properties of the ligands is proposed. We also investigated which residues were involved in the binding of a set of properly synthesised ligands and which were required for fitting inside the binding pocket. Olfactive stimulation of the olfactory receptor with odorous molecules was also investigated, using calcium imaging or electrophysiological recordings.

Research article: The human olfactory receptor 17-40: Requisites for fitting into the binding pocket

To gain structural insight on the interactions between odorants and the human olfactory receptor, we did homology modelling of the receptor structure, followed by molecular docking simulation with ligands. Molecular dynamics simulation on the structures resulting from docking served to estimate the binding free energy of the various odorant families. A correlation with the odorous properties of the ligands is proposed. We also investigated which residues were involved in the binding of a set of properly synthesised ligands and which were required for fitting inside the binding pocket. Olfactive stimulation of the olfactory receptor with odorous molecules was also investigated, using calcium imaging or electrophysiological recordings.

Thermal mud maturation: organic matter and biological activity

Many of the therapeutic and cosmetic treatments offered in spas are centred on mud therapy, to moisturize the skin and prevent skin ageing and rheumatic diseases. Thermal mud is a complex matrix composed of organic and inorganic elements which contribute to its functions. It is a natural product derived from the long mixing of clay and thermal water. During its maturation, organic substances are provided by the microalgae, which develop characteristic of the composition of thermal water.

New multifunctional surfactants from natural phenolic acids.

Several new multifunctional molecules derived from natural sources such as amino acids and hydroxycinnamic acids were synthesized. They exhibit various activities such as emulsifying, UV-protecting, and radical scavenging, thereby conforming to the latest requirements for cosmetic ingredients. The synthesis comprises only a few steps: (i) the amino acid, the acid groups of which are protected by esterification, is coupled with ferulic or caffeic acid; (ii) the p-hydroxyl group of the cinnamic derivative reacts with dodecyl bromide in the presence of potassium carbonate (the resulting compounds are highly lipophilic and tested as water/oil (W/O) emulsifiers); (iii) these molecules, by deprotonating the acid groups of the amino acids, with successive salification, are more hydrophilic, with stronger O/W emulsifying properties. The new multifunctional surfactants might prove useful for the treatment of multiple skin conditions, including loss of cellular antioxidants, damage from free radicals, damage from UV, and others.

Improving photoprotection: 4-methylbenzylidene camphor microspheres

Abstract We propose a new approach for photoprotection. 4-Methylbenzylidene camphor (4-MBC), one of the most widely used UV filters, was encapsulated in microspheres, with a view to overcoming problems (percutaneous absorption, photodegradation and lack of lasting effect) arising with organic sunscreens, and to achieve safe photoprotection. We focused on this filter in the light of the Cosmetics Europe opinion concerning its possible effects on the thyroid gland. Microspheres were prepared by emulsification–solvent evaporation, using different amounts of 4-MBC and characterized for morphology, encapsulation efficiency and particle size. The particles were then mixed in O/W emulsions. The in vitro sun protection factors, in vitro release and photostability were investigated and compared with emulsions containing the free sunscreen. The new microspheres offer good morphology and loading (up to 40%), and the same photoprotection as the free filter while at the same time protecting it from photodegradation. The systems also give a slower release from the emulsions.

Comparison of the conformation of floral odorants: an NMR and molecular dynamics studyElectronic supplementary information (ESI) available: additional NMR data for compounds 1???4. See http://www.rsc.org/suppdata/p2/b2/b205255e/

Odorous molecules, cis- and trans-4-methylcyclohexyl tetrahydrofuran-2-yl or pyranyl ethers, have been studied from the points of view of conformation and dynamics with the aim of extracting information on the relationships between white flower odour and structure. Both NMR and molecular dynamics analyses showed that cis derivatives, endowed with a main white flower note, have a bent structure corresponding to an oval molecular shape; the trans derivatives, exhibiting different odours, possess an extended structure corresponding to a cylindrical molecular shape. This comparison was also applied to two aromatic ethers both with a main floral note, 4-tert-butylphenyl tetrahydropyran-2-yl ether and 4-isopropylphenyl tetrahydrofuran-2-yl ether. These molecules also have similar conformations. All conformations for all molecules are independent of the solvent used, CDCl3 or [2H6]DMSO (NMR) or vacuum, CHCl3 or DMSO (molecular dynamics).