Exploiting the Complementarity between Dereplication and Computer-Assisted Structure Elucidation for the Chemical Profiling of Natural Cosmetic Ingredients: <i>Tephrosia purpurea</i> as a Case Study

The aqueous-ethanolic extract of <i>Tephrosia purpurea</i> seeds is currently exploited in the cosmetic industry as a natural ingredient of skin lotions. The aim of this study was to chemically characterize this ingredient by combining centrifugal partition extraction (CPE) as a fractionation tool with two complementary identification approaches involving dereplication and computer-assisted structure elucidation. Following two rapid fractionations of the crude extract (2 g), seven major compounds namely, caffeic acid, quercetin-3-<i>O</i>-rutinoside, ethyl galactoside, ciceritol, stachyose, saccharose, and citric acid, were unambiguously identified within the CPE-generated simplified mixtures by a recently developed ¹³C NMR-based dereplication method. The structures of four additional compounds, patuletin-3-<i>O</i>-rutinoside, kaempferol-3-<i>O</i>-rutinoside, guaiacylglycerol 8-vanillic acid ether, and 2-methyl-2-glucopyranosyloxypropanoic acid, were automatically elucidated by using the Logic for Structure Determination program based on the interpretation of 2D NMR (HSQC, HMBC, and COSY) connectivity data. As more than 80% of the crude extract mass was characterized without need for tedious and labor-intensive multistep purification procedures, the identification tools involved in this work constitute a promising strategy for an efficient and time-saving chemical profiling of natural extracts

Unveiling the Interplay Between Diffusing CO₂ and Ethanol Molecules in Champagne Wines by Classical Molecular Dynamics and ¹³C NMR Spectroscopy

The diffusion coefficients of carbon dioxide (CO₂) and ethanol (EtOH) in carbonated hydroalcoholic solutions and Champagne wines are evaluated as a function of temperature by classical molecular dynamics (MD) simulations and ¹³C NMR spectroscopy measurements. The excellent agreement between theoretical and experimental diffusion coefficients suggest that ethanol is the main molecule, apart from water, responsible for the value of the CO₂ diffusion coefficients in typical Champagne wines, a result that could likely be extended to most sparkling wines with alike ethanol concentrations. CO₂ and EtOH hydrodynamical radii deduced from viscometry measurements by applying the Stokes–Einstein relationship are found to be mostly constant and in close agreement with MD predictions. The reliability of our approach should be of interest to physical chemists aiming to model transport phenomena in supersaturated aqueous solutions or water/alcohol mixtures

¹³C NMR and LC-MS Profiling of Stilbenes from Elicited Grapevine Hairy Root Cultures

Resveratrol and related oligostilbenes are defense molecules produced by grapevine in response to stresses including various elicitors or signal molecules. Together with their prominent role <i>in planta,</i> these compounds have been the center of much attention in recent decades due to their pharmacological properties. The cost-effective production of resveratrol derivatives such as viniferins or more structurally complex stilbene oligomers remains a challenging task. In this study, the chemical diversity of stilbenes produced by <i>Vitis vinifera</i> Pinot Noir hairy roots was investigated after elicitation for 4 days with a mixture of methyl jasmonate (100 μM) and cyclodextrins (50 mM). Two crude extracts obtained from the culture medium and from the hairy roots were fractionated by centrifugal partition chromatography. The fractions were chemically investigated by two complementary identification approaches involving a ¹³C NMR-based dereplication method and liquid chromatography coupled to mass spectrometry (LC-MS). In total, groups of 21 and 18 molecules, including flavonoids and stilbenes, were detected in the culture medium and root extracts, respectively. These included resveratrol monomers, dimers, trimers, and a tetramer, thus highlighting the ability of elicited hairy root culture systems to synthesize a wide diversity of secondary metabolites of pharmaceutical significance. The main compounds were unambiguously identified as <i>trans</i>-resveratrol, ε-viniferin, <i>trans</i>-piceatannol, pallidol, scirpusin A, eriodictyol, naringenin, vitisin B, and maackin

A cross-platform format to associate NMR-extracted data (NMReDATA) to chemical structures

Poster presented at EUROMAR Meeting July 201

A cross-platform format to associate NMR-extracted data (NMReDATA) to chemical structures

Poster presented at SMASHNMR meeting Sep 201