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Papers by Maria-cruz Figueroa-espinoza

Molecules, 2018

Anthocyanins are water-soluble phenolic pigments. However, their poor solubility in lipidic media... more Anthocyanins are water-soluble phenolic pigments. However, their poor solubility in lipidic media limits their use. This hurdle can be overcome with the lipophilization of anthocyanins, which consists of adding an aliphatic chain to a hydrophilic compound, in order to increase its solubility in lipids. Still, the unspecific chemical lipophilization of anthocyanin-esters produces molecules with different properties from their precursors. In this work, experimental changes of anthocyanin-esters obtained by chemical lipophilization are investigated in silico aiming specifically at observing their molecular behavior and comparing it with their anthocyanin precursor. Thus, the analysis of delphinidin 3-O-sambubioside and its esters employing Density Functional Theory (DFT) methods, such as the hybrid functional B3LYP in combination with the 6-31++G(d,p) Pople basis set, provides the ground state properties, the local reactivity and the molecular orbitals (MOs) of these compounds. Excited states properties were analyzed by TD-DFT with the B3LYP functional, and the M06 and M06-2X meta-GGA functionals. Local reactivity calculations showed that the electrophilic site for all the anthocyanin-esters was the same as the one for the anthocyanin precursor, however the nucleophilic site changed depending localization of the esterification. TD-DFT results indicate that the place of esterification could change the electronic transitions and the MOs spatial distribution.

Phenolic compounds represent a huge amount of potential bioactive candidates. Concomitantly, ther... more Phenolic compounds represent a huge amount of potential bioactive candidates. Concomitantly, there is a need of conceiving effective delivery systems that would deliver such molecules to the specific locations where they would express their optimal activities. Deep Eutectic Solvents (DES) have emerged recently. These are composed of two or more components that are able to self-associate by non-covalent interactions to form a mixture with a phase transition temperature (solid-liquid) significantly lower than that of each individual component. Recently, the term Natural Deep Eutectic Solvents (NaDES) was used to describe such a DES obtained by combining molecules abundantly present in the cellular constituents. It is postulated that NaDES may be an alternative medium to water and lipids in living organisms, and although their accurate role and discovery in cells is still in investigation, their presence could explain numerous biological processes such as the biosynthesis or storage of various non-water soluble metabolites and macromolecules. The molecules forming a NaDES are connected to one another through a well-organized tridimensional system with optimum interactions via inter- and intra- molecular hydrogen-bonding. From that state of the art, we have set the hypothesis that NaDES paired with bioactive molecules could result in an efficient new delivery system. Herein, we present some examples on the activity of such formulated antioxidants in cell systems and heterophasic media

Statement of the Problem: NaDES (natural deep eutectic solvents) are new natural solvents in gree... more Statement of the Problem: NaDES (natural deep eutectic solvents) are new natural solvents in green chemistry and have been shown to allow better extraction of plant bioactive molecules, particularly phenolic compounds, by comparison to conventional solvents. NaDES would allow higher phenolic compounds absorption in mice following oral administration. However, there is a lack of information regarding their in vivo safety. The purpose of this short study was to verify the safety in rats of a mixture of polyphenols extracted from green coffee beans with NaDES. Materials & Methods: Green coffee phenolic compounds at 10 mg of chlorogenic acid equivalent/mL were extracted by NaDES betaine:glycerol (mole ratio 1:2) + 10 water (v/v). Twelve 6-weeks-old male Wistar rats were randomized into two groups of 6 animals and gavaged for 14 days either with water or with phenolic NaDES extract. Rat body weight, food consumption and drinking were determined every two days. Rats were then sacrificed and blood and tissues collected. Plasma/serum routine biochemical analyses were performed (glucose, creatinine, lipids, ASAT/ALAT, uric acid, and urea). Lipid (TBARS), protein (thiols and AOPP) and glucose oxidation (AGEs) products were measured in plasma and liver. Liver lipid and glycogen content were also quantified. Findings: oral administration of phenolic NaDES extract induced mortality in 2 mouse. In addition, it induced excessive water consumption, reduced dietary intake and weight loss, hepatomegaly, plasma oxidative stress associated with high blood lipid levels. Conclusion & Significance: this work demonstrated the toxicity of oral administration of the NaDES: betaine/glycerol, under the acute conditions tested. This occurs despite the fact that this NaDES extract contains polyphenols, the beneficial effects of which have been shown to be numerous. Therefore, complementary work is needed to find the best dose and formulation of NaDES that are safe for the environment, animals and ultimately for humans

Journal of the Science of Food and Agriculture, 2019

Background: Coffee pulp (CP), cocoa husk (CH), and pod husk (CPH) are the main agro-residues from... more Background: Coffee pulp (CP), cocoa husk (CH), and pod husk (CPH) are the main agro-residues from coffee and cocoa industries. They are sources of useful biomolecules, such as phenolic compounds, fibers, and alkaloids, among others. In this study, different compositions of deep eutectic solvents (DES) were investigated as a green and sustainable extraction media, with respect to their extraction capacity. The extraction yields were evaluated using heat stirring assisted extraction (HSE) or ultrasound-probe assisted extraction (UPAE). Results: The results showed an important effect of the DES composition. Choline chloride (ChCl) based-DES were the most effective, specifically lactic acid:ChCl (2:1 mole ratio), and the extraction capacity of DES was higher with UPAE (3 min/constant duty cycle (200 W)), in comparison with HSE (1h / 30 min). Chlorogenic acid, caffeine, and theobromine were identified as the main bioactive compounds. Interestingly, under specific conditions, DES allowed the formation of a molecule, identified as furfural by UPLC-MS, which could not be obtained using conventional extraction solvent (EtOH 70 % v/v). Conclusion: DES showed a sustainability and high extraction capacity of biomolecules. In addition, their use as extraction solvents could lead to the formation and production of valuable building block molecules from plant biomass.

Cellulose, 2019

The present work describes the production of novel highly hydrated cellulose microfibrils (CMFs) ... more The present work describes the production of novel highly hydrated cellulose microfibrils (CMFs) with unique morphology from coffee pulp waste using specific chemical treatments. The asproduced CMFs were successfully characterized and then used as an adsorbent for removal of methylene blue (MB) from concentrated aqueous solutions. Surprisingly, it was found that the novel CMFs display high water-uptake ability, with a maximum swelling ratio of 265%, and that they form an entangled hydrated network gel in water. The morphological observation and nitrogen adsorption measurement demonstrated that the extracted CMFs exhibit an average fibril diameter of 11.5 lm and mesoporous structure with an average pore size of 6.37 nm. These special features make the as-produced CMFs excellent candidates to be used as adsorbents for removal of MB from concentrated solutions. The performed adsorption studies determined that the adsorption equilibrium was reached within 90 min. The adsorption kinetics data were well fitted to the pseudo-secondorder kinetic model, and the adsorption isotherms were well described by the Freundlich isotherm model. In addition, the maximum adsorption capacity was 182.5 mg/g, much higher than that determined for other previously reported cellulose-based adsorbents. Through this study, we have demonstrated a possible strategy to give an added value to the coffee pulp waste, a by-product of the coffee processing industry, which is rich in cellulose, inexpensive and renewable source. Indeed, the extracted CMFs are very attractive for developing a sustainable and economically viable bio-sourced material for future growth of cellulose use in advanced applications.

Microbial Pathogenesis, 2013

The antifungal activities of 5-O-caffeoyl quinic acid (5-CQA) and of methyl, butyl, octyl, and do... more The antifungal activities of 5-O-caffeoyl quinic acid (5-CQA) and of methyl, butyl, octyl, and dodecyl esters or 5-CQA, were tested on five toxigenic moulds from the Aspergillus genus (Aspergillus flavus, Aspergillus nomius, Aspergillus ochraceus, Aspergillus parasiticus, Aspergillus westerdijkiae). These mycotoxin producers' moulds may contaminate many types of food crops throughout the food chain posing serious health hazard to animals and humans. The use of chemical methods to decrease mycotoxin producer moulds contamination on food crops in the field, during storage, and/or during processing, has been proved to be efficient. In this work, the antifungal effect of 5-CQA and a homologous series of 5-CQA esters (methyl, butyl, octyl, dodecyl), was investigated using the microdilution method and the minimum inhibitory concentrations (MIC 50 and MIC 80). All molecules presented antifungal activity, and two esters showed a MIC for all fungi: octyl (MIC 50 0.5e0.75 mg/mL, MIC 80 ¼ 1.0e1.5 mg/mL) and dodecyl (MIC 50 ¼ 0.75e1.25 mg/mL) chlorogenates. Dodecyl chlorogenate showed a MIC 80 (1.5 mg/mL) only for A. parasiticus. The maximum percent of growth inhibition on aspergillii was observed with octyl (78.4 e92.7%) and dodecyl (54.5e83.7%) chlorogenates, being octyl chlorogenate the most potent antifungal agent. It was thus concluded that lipophilization improved the antifungal properties of 5-CQA, which increased with the ester alkyl chain length, exhibiting a cutoff effect at 8 carbons. As far as we know, it is the first report demonstrating that lipophilization may improve the antifungal activity of 5-CQA on five toxigenic moulds from the Aspergillus genus. Lipophilization would be a novel way to synthesize a new kind of antifungal agents with a good therapeutic value or a potential use as preservative in food or cosmetics.

Biotechnology Letters, 2004

The synthesis of dodecyl pyroglutamate (or pyroglutamate lauroyl ester) was achieved in a two-ste... more The synthesis of dodecyl pyroglutamate (or pyroglutamate lauroyl ester) was achieved in a two-step process involving a pyroglutamic acid alkyl ester intermediate. The reaction was carried out either by lipase or by chemical catalysis using ion exchange resin. Among the various tested lipases, the one from Candida antarctica B gave the best results allowing 73% formation of the desired ester after 6 h. Comparing the efficiency of this latter lipase with the one of Amberlyst IR120H resin in catalyzing this reaction, the biocatalyst gave a molar yield of pyroglutamate lauroyl ester of 79% compared to 69% when using the ion exchange resin starting with 1.04 mmol substrate in each case.

Encyclopedia of Food Chemistry

Lipophilized antioxidants are amphiphilic molecules constituted of a lipid moiety covalently link... more Lipophilized antioxidants are amphiphilic molecules constituted of a lipid moiety covalently linked to a polar group possessing antioxidant properties. They are multifunctional molecules possessing interesting physicochemical (antioxidant, surface active) and biological (antimicrobial, antiviral, antiinflammatory, anticarcinogenic, etc.) properties. They can be used to limit lipid oxidation in heterogeneous systems such as food and nonfood emulsions, liposomes, microorganisms, and cultured cells. Their activity is related to their hydrophobicity and follows a nonlinear trend named “cut-off effect,” meaning that it increases progressively with hydrophobicity until a critical point, beyond which activity collapses. The antioxidant and biological properties in heterogeneous system of lipophilized antioxidants are dictated by their reducing activity, the parent molecule toxicity, their hydrophobicity, and the position of the lipophilic group in the parent molecule. The hydrophilic/lipophilic balance of lipophilized antioxidants influences their partitioning in every phase constituting the dispersed system, and their capacity to self-aggregate, e.g., to form micelles, and/or with other molecules present, e.g., in the continuous, discontinuous, or interface in an emulsion, or in membranes in microorganisms or cells. Therefore, lipophilized antioxidants possess an interesting potential to be used as antioxidant and biological agents in food, cosmetics, and pharmaceutical products, since most of them exist as complex heterogeneous lipid dispersions

Centre de coopération internationale en recherche agronomique pour le développement 73, rue J.-F.

Hybrid of gas/liquid obtain under specific conditions of temperature and pressure (most popular i... more Hybrid of gas/liquid obtain under specific conditions of temperature and pressure (most popular is carbon dioxide). Tuning properties, strong and unusual solvation properties. Restricted range of molecule solubility, high cost. Biomass-derived solvents: such as EtOH, limonene, ethyl lactate, glycerol, or 2-methyltetrahydrofuran. Biorenewable, innocuous, and not very expensive. Low choice, restricted versatility and solvation properties. (P. Walden) 2003 (AP. Abbott) 2011 (R. Verpoorte) Organic solvents: such as acetone and ethyl acetate, or alkyl alcohols such as methanol (MeOH), ethanol (EtOH), and propanol. Large choice with several and different solubilization and extraction capacities. Accumulation in the atmosphere (low boiling points), flammability, high toxicity, limited-biodegradability, synthetic from fossil source, cost. Water Natural ressource, easy to obtain, low cost, safe. Restricted solvation properties, high reactivity. Mixing of at least two molecules in such proportions that they can lead to a liquidus temperature significantly lower than pure equivalents. BIOCATALYSIS AND SOLVENTS Solvents obtained by mixing ammonium/phosphonium salts with hydrogen-bond donors (HBD) in proportions such that, at the "eutectic point", the mixture behaves like a pure compound with a melting point lower than that of each pure component. Eutectic point Variable eutectic point depending on Salt ant HBD type and ratio Hydrogen-Bond Donor (HBD) Alcohols, Acids, Amines, Amides, Thiols… Ammonium (N +) or phosphonium (P+) salt Choline chloride, Betaine Methyltriphenylphosphonium bromide Lower and unique melting point temperature

Measurement of antioxidant capacity of olive leaf flavonoids & secoiridoids by the use of a conju... more Measurement of antioxidant capacity of olive leaf flavonoids & secoiridoids by the use of a conjugated autoxidizable triene assay [1] Laguerre et al. Conjugated autoxidizable triene (CAT) assay: A novel spectrophotometric method for Determination of antioxidant capacity using triacylglycerol as ultraviolet probe.

Chlorogenic acid (CGA) extracted from Mexican green coffee beans (Coffea arabica) was esterified ... more Chlorogenic acid (CGA) extracted from Mexican green coffee beans (Coffea arabica) was esterified to alcohols of different chain length (methanol, butanol, octanol, and dodecanol). CGA and lipophilized CGA (L-CGA) antifungal activities were tested on five toxigenic moulds from the Aspergillus genus (A. flavus, A. nomius, A. ochraceus, A. parasiticus, and A. westerdijkiae) using the microdilution method and the minimum inhibitory concentrations (MIC50 and MIC90) were determined. All molecules presented antifungal activity, however, only dodecyl chlorogenate and octyl chlorogenate showed a MIC50 for all fungi. Octyl chlorogenate had a MIC90 for A. flavus, A. parasiticus, and A. nomius. Lipophilization improves hydrophobicity of CGA resulting in amphiphilic molecules with antifungal properties. (Resume d'auteur)

LWT, 2021

Abstract The effect of the presence of surfactant micelles and of the mode of incorporation (pre-... more Abstract The effect of the presence of surfactant micelles and of the mode of incorporation (pre-homogenization or post-homogenization) on the antioxidant efficiency of a homologous series of n-alkyl gallates phenolipids (G0, G3, G8, G12 or G16) was investigated in oil-in-water nanoemulsions. In both absence and presence of surfactant micelles, G12 and G16 were the best antioxidants. The effect of the mode of incorporation was modulated by the presence of surfactant micelles. In absence of surfactant micelles, G8 and G16 had higher efficiency when incorporated pre-homogenization, suggesting that the mode of incorporation promoted a distinct initial distribution of these compounds. In contrast, in presence of surfactant micelles, the antioxidants could be incorporated in any phases without efficiency loss. These results demonstrate the important role of surfactant micelles in modulating the antioxidant efficiency and could be used by the food industry to optimize emulsion formulations.

Chemistry and Physics of Lipids, 2017

Highlights  A new oxidation high-throughput assay based on the UV properties of a phospholipid p... more Highlights  A new oxidation high-throughput assay based on the UV properties of a phospholipid probe is proposed.  Two site of oxidation (membrane or aqueous phase) were developed.  The new method, tested with several antioxidants, is rapid and reproducible.  Aqueous or membrane-induced oxidations provide further information on the antioxidants efficacy.

Food & Function, 2019

Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are isoprostanoids that result from the peroxi... more Phytoprostanes (PhytoPs) and phytofurans (PhytoFs) are isoprostanoids that result from the peroxidation of α-linolenic acid and are biomarkers of oxidative stress in plants and humans.

European Journal of Lipid Science and Technology, 2019

† This article has been accepted for publication and undergone full peer review but has not been ... more † This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

Journal of Agricultural and Food Chemistry, 2018

Natural deep eutectic solvents (NaDES) are new natural solvents in green chemistry that in some c... more Natural deep eutectic solvents (NaDES) are new natural solvents in green chemistry that in some cases have been shown to allow better extraction of plant bioactive molecules compared to conventional solvents and higher phenolic compound absorption in rodents. However, there is a serious lack of information regarding their in vivo safety. The purpose of this study was to verify the safety of a NaDES (betaine:glycerol (1:2 mole ratio) of water) extract from green coffee beans, rich in polyphenols. Twelve 6-week-old male Wistar rats were randomized into two groups of 6 animals each and twice daily gavaged for 14 days either with 3 mL of water or 3 mL of phenolic NaDES extract. Oral administration of phenolic NaDES extract induced mortality in two rats. In addition, it induced excessive water consumption, reduced dietary intake and weight loss, hepatomegaly, and plasma oxidative stress associated with high blood lipid levels. In conclusion, this work demonstrated the toxicity of oral administration of the selected NaDES under a short-term condition. This occurs despite the fact that this NaDES extract contains polyphenols, whose beneficial effects have been shown. Therefore, complementary work is needed to find the best dose and formulation of NaDES that are safe for the environment and animals and ultimately for humans.

European Journal of Lipid Science and Technology, 2018