Marisanna Centini

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).

Quinoline alkaloids in honey: Further analytical (HPLC-DAD-ESI-MS, multidimensional diffusion-ordered NMR spectroscopy), theoretical and chemometric studies

The wound-healing properties of honey are well established and it has been suggested that, among its pharmaco-active constituents, kynurenic acid (KA) exerts antinociceptive action on injured tissue by antagonizing NMDA at peripheral GABA receptors. The aim of this study was to investigate the quantitative profile of KA and of two recently identified, structurally related derivatives, 3-pyrrolidinyl-kynurenic acid (3-PKA) and its gamma-lactamic derivative (gamma-LACT-3-PKA), by examining their mass spectrometric behavior, in honeys from different botanical sources. We used a combination of HPLC-DAD-ESI-MS and NMR techniques (one-dimensional (1)H NMR and diffusion-ordered spectroscopy NMR). Chestnut honey constantly contained KA (2114.9-23 g/kg), 3-PKA (482.8-80 mg/kg) and gamma-LACT-3-PKA (845.8-32 mg/kg), confirming their reliability as markers of origin. A new metabolite, 4-quinolone (4-QUIN), was identified for the first time in one chestnut honey sample (743.4 mg/kg). Small amounts of KA were found in honeydew, sunflower, multifloral, almond and eucalyptus honeys, in the range of 23.1-143 mg/kg, suggesting contamination with chestnut honey. Total phenol content (TPC) was in the range from 194.9 to 1636.3 mg(GAE)/kg and total antiradical activity (TAA) from 61 to 940 mg/(GAE)/kg), depending on the botanical origin. Principal component analysis (PCA) was then done on these data. The three different clusters depicted: (i) antinociceptive activity from KA and/or its derivatives, typical of chestnut honey; (ii) antioxidant/radical scavenging activity by antioxidants responsible for the antiinflammatory action (dark honeys); (iii) peroxide-dependent antibacterial activity due to H(2)O(2) production by glucose oxidase in honey. The PCA findings provide useful indications for the dermatologist for the treatment of topical diseases, and the profiling of KA and its derivatives may shed light on new aspects of the kynurenine pathway involved in tryptophan metabolism.

GC–MS profiling of the phytochemical constituents of the oleoresin from Copaifera langsdorffii Desf. and a preliminary in vivo evaluation of its antipsoriatic effect

Copaiba is the oleoresin (OR) obtained from Copaifera (Fabaceae), a neotropical tree which grows in Amazon regions. The balsam, constituted by an essential oil and a resinous fraction is used as folkloristic remedy in the treatment of several inflammatory diseases and for its antioxidant and antibacterial properties. Aim of this work was (a) to carry out a characterization by GC-MS of the volatile and nonvolatile constituents of Copaifera langsdorffii Desf. oleoresin (OR); (b) to investigate the mechanism of its anti-inflammatory activity; (c) to evaluate its antipsoriatic effect after oral intake/topical application. The volatile fraction (yield: 22.51%, w/w) shows: α-bergamotene (48.38%), α-himachalene (11.17%), β-selinene (5.00%) and β-caryophyllene (5.47%). The OR residue (77.49%, w/w), after derivatization, showed as main constituents the following compounds: copalic, abietic, daniellic, lambertinic, labd-7-en-15-oic, pimaric, isopimaric acids and kaur16-en18-oic acid. Preincubation of LPS-stimulated human THP-1 monocytes with increasing concentrations of the OR purified fraction (OR-PF), containing diterpene acids, diterpenes and sesquiterpenes, reduced the release of pro-inflammatory cytokines (IL-1β, IL-6, TNFα) in a dose-range of 0.1-10 μM. In addition, in cell culture system of human THP-1 monocytes, 1 μM OR-PF counteracts LPS-driven NF-κB nuclear translocation. In a preliminary clinical trial three patients affected by chronic psoriasis, treated with oral intake or topical application of the OR, exhibited a significant improvement of the typical signs of this disease, i.e. erythema, skin thickness, and scaliness. In conclusion, the results of this work, beside an extensive analytical characterization of the OR chemical composition, provide strong evidences that its anti-inflammatory activity is related to the inhibition of the NF-κB nuclear translocation, and consequently of proinflammatory cytokines secretion.

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.

Substantivity of sunscreens —in vitro evaluation of the transdermal permeation characteristics of some benzophenone derivatives

The in vitro permeation through excised hairless mouse skin of a series of 4‐O‐(N, N‐dimethylaminoalkyl)‐benzophenones, non‐quaternarized and quaternarized, and of two commercial benzophenone sunscreens, taken as reference compounds, was investigated. The aim of the study was to verify the skin penetration of the highly skin‐substantive quaternary ammonium derivatives, in comparison with their parent, non‐quaternarized compounds. While the quaternary derivatives proved unable to permeate the skin during the period of observation (45 h), their parent amine hydrochlorides and the reference sunscreens (2‐hydroxy‐4‐methoxy‐benzophenone‐5‐sulphonic acid and 2,2′‐dihydroxy‐4,4′‐dimethoxy‐benzophenone 5,5′‐sodium disulphonate), showed appreciable transdermal fluxes.

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.

COMPARATIVE CONFORMATIONAL AND DYNAMICAL STUDY OF SOME N-QUATERNARIZED UV FILTERS : STRUCTURE-ACTIVITY RELATIONSHIPS

A comparative conformational and dynamical study of a series of structurally related molecules with UV-filtering properties, i.e. N,N-dimethyl-N-[2-(4-benzoyl-2-hydroxyphenoxy)ethyl]-N-dodecyl ammonium bromide 2, N,N-dimethyl-N-[6-(4-benzoylphenoxy)hexyl]-N-dodecyl ammonium bromide 3 and N,N-dimethyl-N-[3-(salicyloylamino)propyl]-N-dodecyl ammonium bromide 5, has been performed in CDCl3 and [2H6] DMSO solutions. The main conformers of 2 and 3 (extensively folded conformations) and 5 (‘linear’ conformations) were determined by means of selective spin-lattice proton relaxation rates, carbon spin-lattice relaxation rates and 1D nuclear Overhauser effects. On the basis of these results a possible correlation between conformation and antibacterial activity is discussed.