Antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, on Leishmania (Leishmania) amazonensis.

BACKGROUND: Leishmaniasis, a neglected disease caused by the parasite Leishmania, is treated with drugs associated with high toxicity and limited efficacy, in addition to constant reports of the emergence of resistant parasites. In this context, snake serums emerge as good candidates since they are natural sources with the potential to yield novel drugs. OBJECTIVES: We aimed to show the antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, against Leishmania (Leishmania) amazonensis. METHODS: Promastigotes forms were exposed to γCdcPLI, and we assessed the parasite viability and cell cycle, as well as invasion and proliferation assays. FINDINGS: Despite the low cytotoxicity effect on macrophages, our data indicate that γCdcPLI has a direct effect on parasites promoting an arrest in the G1 phase and reduction in the G2/M phase at the highest dose tested. Moreover, this PLA2 inhibitor reduced the parasite infectivity when promastigotes were pre-treated. Also, we demonstrated that the γCdcPLI treatment modulated the host cell environment impairing early and late steps of the parasitism. MAIN CONCLUSIONS: γCdcPLI is an interesting tool for the discovery of new essential targets on the parasite, as well as an alternative compound to improve the effectiveness of the leishmaniasis treatment.

Assessment of mouth opening before and after head and neck radiotherapy in patients with intraoral stents.

Background: We evaluated the evolution of mouth opening before and after radiotherapy of the head and neck in patients using intraoral stents. Materials and methods: Twenty-one patients with head and neck cancer who were indicated for radiotherapy participated in this study. Maximum interincisal opening measurements were performed before and after radiotherapy. Paired analyses of the pre- and post-radiotherapy groups were performed using paired samples t-tests and correlation analyses using Spearman's correlation test, with p < 0.05 considered statistically significant. Results: Paired analyses of the pre- and post-radiotherapy groups revealed a statistically significant reduction in post-radiotherapy maximum interincisal opening (p < 0.001). However, only four individuals were diagnosed with trismus after radiotherapy. Regarding the correlation tests, no statistically significant differences were observed between the differences in pre- and post-radiotherapy maximum interincisal opening values and the study variables. Conclusion: The use of prosthetic devices during head and neck radiotherapy can reduce radiation doses in areas of no interest, thereby preventing the acute and late toxicities associated with cancer therapy.

Biochemical characterization and assessment of leishmanicidal effects of a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom (CollinLA AO-I).

This study reports the isolation of CollinLAAO-I, a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom, its biochemical characterization and leishmanicidal potential in Leishmania spp. CollinLAAO-I (63.1 kDa) was successfully isolated with high purity using two chromatographic steps and represents 2.5% of total venom proteins. CollinLAAO-I displayed high enzymatic activity (4262.83 U/mg/min), significantly reducing after 28 days. The enzymatic activity of CollinLAAO-I revealed higher affinity for hydrophobic amino acids such as L-leucine, high enzymatic activity in a wide pH range (6.0-10.0), at temperatures from 0 to 25 °C, and showed complete inhibition in the presence of Na+ and K+. Cytotoxicity assays revealed IC50 of 18.49 and 11.66 µg/mL for Leishmania (L.) amazonensis and Leishmania (L.) infantum, respectively, and the cytotoxicity was completely suppressed by catalase. CollinLAAO-I significantly increased the intracellular concentration of reactive oxygen species (ROS) and reduced the mitochondrial potential of both Leishmania species. Furthermore, CollinLAAO-I decreased the parasite capacity to infect macrophages by around 70%, indicating that even subtoxic concentrations of CollinLAAO-I can interfere with Leishmania vital processes. Thus, the results obtained for CollinLAAO-I provide important support for developing therapeutic strategies against leishmaniasis.

A covid-19 como um analisador do sofrimento de enfermeiras: um ensaio teórico / Covid-19 as a suffering analyzer for female nurses: a theoretical essay / El covid-19 como analizador de sufrimiento de enfermeras: un ensayo teórico

Este ensaio propõe que a Covid-19 pode operar como um analisador, dentro da perspectiva da análise institucional, iluminando um determinado modo de organização social que promove profundas desigualdades e ameaça a vida em diversos níveis e revelando as condições sociais, institucionais e políticas de produção de sofrimento no corpo profissional de Enfermagem. A pandemia desvelou um conjunto de marcas relacionadas à profissão, agravadas pela crise sanitária, reforçando a naturalização das relações de cuidado atribuídas ao feminino, bem como um conjunto de clivagens e hierarquias internas à profissão a partir da sinergia de marcadores da diferença, como gênero, cor/raça, classe e geração. Além disso, este trabalho mostra a presença de uma necropolítica nas respostas à pandemia que banaliza a vida e permite morrer determinados grupos sociais. A ideia de "profissionais de linha de frente" é criticada em suas metáforas bélicas, mas tomada como figura de linguagem em sua potência para afirmar que existem corpos que, pelas marcas sociais e históricas e pela interdependência do cuidado, são mais presentes e exigidos e, portanto, mais vulneráveis à doença e ao sofrimento dela decorrente.(AU)

The essay proposes that Covid-19 can operate as an analyzer, within the perspective of institutional analysis, illuminating a certain mode of social organization that promotes profound inequalities and threatens life at various levels, revealing the social, institutional and political conditions for the production of suffering in the professional nursing body. The pandemic would unveil a set of marks related to the profession, aggravated by the sanitary crisis, reinforcing the naturalization of the care relations attributed to the feminine, as well as a set of cleavages and internal hierarchies to the profession from the synergy of markers of difference as gender, color/race, class and generation. The work shows the presence of necropolitics in responses to the pandemic, which trivializes life and allows certain social groups to die. The idea of "front-line professionals" is criticized in its war metaphors, but taken as a figure of speech in its potency to affirm that there are bodies that by social and historical marks, and by the interdependence of care, are more present and demanded, and therefore more vulnerable to disease and the resulting suffering.(AU)

El ensayo propone que el Covid-19 puede funcionar como analizador, desde la perspectiva del análisis institucional, revelando las condiciones sociales, institucionales y políticas de producción de sufrimiento de enfermeras. La pandemia revela algunas marcas relacionadas con la profesión, agravadas por la crisis de salud, reforzando la naturalización de la atribución del cuidado a lo femenino y un conjunto de jerarquías internas de la profesión. El trabajo también muestra la presencia de una necropolítica en las respuestas a la pandemia. La idea de "profesionales de primera línea" es criticada, pero tomada como una figura del lenguaje en su potencia para afirmar que hay cuerpos que, por las marcas sociales e históricas y por la interdependencia del cuidado, están más presentes y demandados, y por lo tanto más vulnerables a la enfermedad.(AU)

Antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, on Leishmania (Leishmania) amazonensis

BACKGROUND Leishmaniasis, a neglected disease caused by the parasite Leishmania, is treated with drugs associated with high toxicity and limited efficacy, in addition to constant reports of the emergence of resistant parasites. In this context, snake serums emerge as good candidates since they are natural sources with the potential to yield novel drugs. OBJECTIVES We aimed to show the antileishmanial effects of γCdcPLI, a phospholipase A2 inhibitor from Crotalus durissus collilineatus snake serum, against Leishmania (Leishmania) amazonensis. METHODS Promastigotes forms were exposed to γCdcPLI, and we assessed the parasite viability and cell cycle, as well as invasion and proliferation assays. FINDINGS Despite the low cytotoxicity effect on macrophages, our data indicate that γCdcPLI has a direct effect on parasites promoting an arrest in the G1 phase and reduction in the G2/M phase at the highest dose tested. Moreover, this PLA2 inhibitor reduced the parasite infectivity when promastigotes were pre-treated. Also, we demonstrated that the γCdcPLI treatment modulated the host cell environment impairing early and late steps of the parasitism. MAIN CONCLUSIONS γCdcPLI is an interesting tool for the discovery of new essential targets on the parasite, as well as an alternative compound to improve the effectiveness of the leishmaniasis treatment.

Biochemical characterization and assessment of leishmanicidal effects of a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom (CollinLA AO-I)

This study reports the isolation of CollinLAAO-I, a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom, its biochemical characterization and leishmanicidal potential in Leishmania spp. CollinLAAO-I (63.1 kDa) was successfully isolated with high purity using two chromatographic steps and represents 2.5% of total venom proteins. CollinLAAO-I displayed high enzymatic activity (4262.83 U/mg/min), significantly reducing after 28 days. The enzymatic activity of CollinLAAO-I revealed higher affinity for hydrophobic amino acids such as L-leucine, high enzymatic activity in a wide pH range (6.0–10.0), at temperatures from 0 to 25 °C, and showed complete inhibition in the presence of Na+ and K+. Cytotoxicity assays revealed IC50 of 18.49 and 11.66 μg/mL for Leishmania (L.) amazonensis and Leishmania (L.) infantum, respectively, and the cytotoxicity was completely suppressed by catalase. CollinLAAO-I significantly increased the intracellular concentration of reactive oxygen species (ROS) and reduced the mitochondrial potential of both Leishmania species. Furthermore, CollinLAAO-I decreased the parasite capacity to infect macrophages by around 70%, indicating that even subtoxic concentrations of CollinLAAO-I can interfere with Leishmania vital processes. Thus, the results obtained for CollinLAAO-I provide important support for developing therapeutic strategies against leishmaniasis.

Impact of a Purified Blueberry Extract on In Vitro Probiotic Mucin-Adhesion and Its Effect on Probiotic/Intestinal Pathogen Systems.

Several arguments have been made to substantiate the need for natural antimicrobials for the food industry. With blueberry extracts, the most compelling are both their healthy connotation and the possibility of obtaining a multipurpose solution that can be an antioxidant, colorant, and antimicrobial. From an antimicrobial perspective, as blueberry/anthocyanin-rich extracts have been associated with a capacity to inhibit harmful bacteria while causing little to no inhibition on potential probiotic microorganisms, the study of potential benefits that come from synergies between the extract and probiotics may be of particular interest. Therefore, the present work aimed to evaluate the effect of an anthocyanin-rich extract on the adhesion of five different probiotics as well as their effect on the probiotics' capacity to compete with or block pathogen adhesion to a mucin/BSA-treated surface. The results showed that, despite some loss of probiotic adhesion, the combined presence of extract and probiotic is more effective in reducing the overall amount of adhered viable pathogen cells than the PROBIOTIC alone, regardless of the probiotic/pathogen system considered. Furthermore, in some instances, the combination of the extract with Bifidobacterium animalis Bo allowed for almost complete inhibition of pathogen adhesion.

Mutagenic and genotoxic activities of Phospholipase A2 Bothropstoxin-I from Bothrops jararacussu in Drosophila melanogaster and human cell lines.

Phospholipase A2 Bothropstoxin-I (PLA2 BthTX-I) is a myotoxic Lys49-PLA2 from Bothrops jararacussu snake venom. In order to evaluate the DNA damage caused by BthTX-I, we used the Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster and Comet assay in HUVEC and DU-145 cells. For SMART, different concentrations of BthTX-I (6.72 to 430 µg/mL) were used and no significant changes in the survival rate were observed. Significant frequency of mutant spots was observed for the ST cross at the highest concentration of BthTX-I due to recombinogenic activity. In the HB cross, BthTX-I increased the number of mutant spots at intermediate concentrations, being 53.75 µg/mL highly mutagenic and 107.5 µg/mL predominantly recombinogenic. The highest concentrations were neither mutagenic nor recombinogenic, which could indicate cytotoxicity in the wing cells of D. melanogaster. In vitro, all BthTX-I concentrations (1 to 50 µg/mL) induced decrease in HUVEC cell viability, as well as in DU-145 cells at concentrations of 10, 25, and 50 µg/mL. The comet assay showed that in HUVEC and DU-145 cells, all BthTX-I concentrations promoted increase of DNA damage. Further studies should be performed to elucidate the mechanism of action of PLA2 BthTX-I and its possible use in therapeutic strategies against cancer.

Antiangiogenic effects of phospholipase A2 Lys49 BnSP-7 from Bothrops pauloensis snake venom on endothelial cells: An in vitro and ex vivo approach.

Antiangiogenic strategies are promising tools for cancer treatment and several other disorders. In this sense, phospholipases A2 (PLA2s) from snake venom have been described to possess antiangiogenic properties. In this study, we evaluated both in vitro and ex vivo antiangiogenic effects induced by BnSP-7, a Lys49 PLA2 isolated from Bothrops pauloensis snake venom. BnSP-7 was able to inhibit endothelial cell (HUVEC) proliferation, which was indeed confirmed by a modulation of cell cycle progression. Interestingly, BnSP-7 also inhibited the adhesion and migration of HUVECs and blocked in vitro angiogenesis in a VEGF-dependent manner, an important proangiogenic factor. Finally, BnSP-7 was capable of inhibiting sprouting angiogenic process through an ex vivo aortic ring assay. Taken together, these results indicate that BnSP-7 has potent in vitro and ex vivo antiangiogenic effect.

Optimizing the extraction of phenolic antioxidants from chestnut shells by subcritical water extraction using response surface methodology.

The objective of this study was to evaluate the optimal Subcritical Water Extraction (SWE) conditions of antioxidants and polyphenols from chestnut shells using Response Surface Methodology (RSM). A central composite design (CCD) was conducted to analyse the time (6-30 min) and temperature (51-249 °C) effects in antioxidant activity (ABTS, DPPH and FRAP) and Total Phenolic Compounds (TPC). TPC ranged from 315.21 to 496.80 mg gallic acid equivalents (GAE)/g DW; the DPPH from 549.23 to 1125.68 mg Trolox equivalents (TE)/g DW; ABTS varied between 631.16 and 965.45 mg ascorbic acid equivalents (AAE)/g DW and FRAP from 2793.95 to 11393.97 mg ferrous sulphate equivalents (FSE)/g DW. The optimal extraction conditions were 30 min/220 °C, revealing excelling scavenging efficiencies against HOCl (IC50 = 0.79 µg/mL) and O2- (IC50 = 12.92 µg/mL) without toxicity on intestinal cells (0.1 µg/mL). The phenolic composition revealed high amounts of pyrogallol and protocatechuic acid. SWE can be a useful extraction technique for the recovery of polyphenolics from chestnut shells.

Antiangiogenic effects of phospholipase A2 Lys49 BnSP-7 from Bothrops pauloensis snake venom on endothelial cells: An in vitro and ex vivo approach

Antiangiogenic strategies are promising tools for cancer treatment and several other disorders. In this sense, phospholipases A2 (PLA2s) from snake venom have been described to possess antiangiogenic properties. In this study, we evaluated both in vitro and ex vivo antiangiogenic effects induced by BnSP-7, a Lys49 PLA2 isolated from Bothrops pauloensis snake venom. BnSP-7 was able to inhibit endothelial cell (HUVEC) proliferation, which was indeed confirmed by a modulation of cell cycle progression. Interestingly, BnSP-7 also inhibited the adhesion and migration of HUVECs and blocked in vitro angiogenesis in a VEGF-dependent manner, an important proangiogenic factor. Finally, BnSP-7 was capable of inhibiting sprouting angiogenic process through an ex vivo aortic ring assay. Taken together, these results indicate that BnSP-7 has potent in vitro and ex vivo antiangiogenic effect.

Infusions and decoctions of dehydrated fruits of Actinidia arguta and Actinidia deliciosa: Bioactivity, radical scavenging activity and effects on cells viability.

Actinidia deliciosa and A. arguta fruits (kiwifruit and kiwiberry, respectively) are an excellent source of bioactive compounds. The aim of this paper is to valorize the fruits that are not commercialized (e.g. due to inadequate size or physical damage) in infusions and decoctions. The antioxidant activity, the scavenging activity against reactive species, the phenolic profile and the intestinal effects of infusions and decoctions of dehydrated fruits were evaluated and compared. Decoctions presented the highest antioxidant activity and a good ability to capture HOCl and NO. The phenolic composition of A. arguta present quinic acid, cis-caftaric acid and its derivatives, caffeoyl hexoside, luteolin glucuronide, quercetin derivatives and myristin, while A. deliciosa extracts were characterized by the presence of quinic acid, caffeic acid and its derivatives and caffeoyl hexoside. No adverse effects were observed on Caco-2 and HT29-MTX cells. Kiwiberry decoctions showed to be the best option to keep the fruits benefits.

Olive pomace as a valuable source of bioactive compounds: A study regarding its lipid- and water-soluble components.

Olive pomace is a major output of olive oil processing. This by-product is a valuable source of bioactive compounds with well-recognized benefits for human health and well-being. In this work, the proximate composition and the profiles of vitamin E (HPLC-DAD-FLD), fatty acids (GC-FID) and phenolics (HPLC-DAD-FL/MSn) were determined. Additionally, a sustainable process for antioxidants extraction - Multi-frequency Multimode Modulated (MMM) ultrasonic technique - was compared to a conventional solid-liquid extraction. The total phenolics content and antioxidant activity (ferric reducing antioxidant power and DPPH scavenging ability) of the extracts were analysed to assess the efficacy of both extraction methodologies. The vitamin E profile of the olive pomace comprised the vitamers α-tocopherol, ß-tocopherol, α-tocotrienol and γ-tocopherol. α-Tocopherol was the major form (2.63 mg/100 g), while the other vitamers were present in amounts lower than 0.1 mg/100 g. The lipid fraction was especially rich in oleic acid (75%), followed by palmitic (10%), linoleic (9%), and stearic (3%) acids. Hydroxytyrosol and comsegoloside represented ≈79% of the total phenolics present in olive pomace. Hydroxytyrosol content was 83.6 mg/100 g, while tyrosol was present in lower amounts (3.4 mg/100 g). Concerning the antioxidants extraction, the MMM technique allowed a faster and higher recovery (p < 0.05) of the compounds, compared to the conventional solid-liquid extraction. By this way, it seems to be a very promising eco-friendly and effective methodology to extract antioxidants from this and other matrices.

Antiparasitic effects induced by polyclonal IgY antibodies anti-phospholipase A2 from Bothrops pauloensis venom.

Activities of phospholipases (PLAs) have been linked to pathogenesis in various microorganisms, and implicated in cell invasion and so the interest in these enzymes as potential targets that could contribute to the control of parasite survival and proliferation. Chicken eggs immunized with BnSP-7, a Lys49 phospholipase A2 (PLA2) homologue from Bothrops pauloensis snake venom, represent an excellent source of polyclonal antibodies with potential inhibitory activity on parasite PLAs. Herein, we report the production, characterization and anti-parasitic effect of IgY antibodies from egg yolks of hens immunized with BnSP-7. Produced antibodies presented increasing avidity and affinity for antigenic toxin epitopes throughout immunization, attaining a plateau after 4weeks. Pooled egg yolks-purified anti-BnSP-7 IgY antibodies were able to specifically recognize different PLA2s from Bothrops pauloensis and Bothrops jararacussu venom. Antibodies also neutralized BnSP-7 cytotoxic activity in C2C12 cells. Also, the antibodies recognized targets in Leishmania (Leishmania) amazonensis and Toxoplasma gondii extracts by ELISA and immunofluorescence assays. Anti-BnSP-7 IgY antibodies were cytotoxic to T. gondii tachyzoite and L. (L.) amazonensis promastigotes, and were able to decrease proliferation of both parasites treated before infection. These data suggest that the anti-BnSP-7 IgY is an important tool for discovering new parasite targets and blocking parasitic effects.

Structure-Based Discovery of Thiosemicarbazone Metalloproteinase Inhibitors for Hemorrhage Treatment in Snakebites.

The venoms of snakes are composed by many toxins, which are responsible for various toxic effects including intense pain, bleeding disorders, and local tissue damage caused by hemorrhage and necrosis. The snake venom metalloproteinases (SVMPs) are proteolytic zinc-dependent enzymes acting in different hemostatic mechanisms. In this work, a structure-based molecular modeling strategy was used for the rational design, by means of a homology 3D model of an SVMP isolated from Bothrops pauloensis venom (BpMP-I), followed by synthesis and in vitro evaluation of new thiosemicarbazones as the first inhibitors of the B. pauloensis SVMP. Besides being effective for the SVMP inhibition, two molecules were shown to be effective also in vivo, inhibiting hemorrhage caused by the B. pauloensis whole venom. Docking studies on metalloproteinases from other snake species suggest that the thiosemicarbazones activity is not confined to BpMP-I, but seems to be a common feature of metzincins.

Identification and quantification of anthocyanins in fruits from Neomitranthes obscura (DC.) N. Silveira an endemic specie from Brazil by comparison of chromatographic methodologies.

Neomitranthes obscura (DC.) N. Silveira is a Brazilian fruit belonging to the Myrtaceae family that contains anthocyanins in the peel and was studied for the first time in this work. Delphinidin-3-O-galactoside, delphinidin-3-O-glucoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, cyanidin-3-O-arabinoside, petunidin-3-O-glucoside, pelargonidin-3-O-glucoside, peonidin-3-O-galactoside, peonidin-3-O-glucoside, cyanidin-3-O-xyloside were separated and identified by LC/DAD/MS and by co-elution with standards. Reliable quantification of anthocyanins in the mature fruits was performed by HPLC/DAD using weighted linear regression model from 0.05 to 50mg of cyaniding-3-O-glucoside L(-1) because it gave better fit quality than least squares linear regression. Good precision and accuracy were obtained. The total anthocyanin content of mature fruits was 263.6 ± 8.2 mg of cyanidin-3-O-glucoside equivalents 100 g(-1) fresh weight, which was in the same range found in literature for anthocyanin rich fruits.

Evolution of phenolic composition of red wine during vinification and storage and its contribution to wine sensory properties and antioxidant activity.

The objective of this work was to study the evolution of the phenolic composition of red wine during vinification and storage and its relationship with some sensory properties (astringency and bitterness) and antioxidant activities. Thus, red wine was made by a classic vinification method with Castelão and Tinta Miúda grapes (Vitis vinifera L.) harvested at maturity (3:2; w/w). Samples were taken at 2 and 7 days of maceration, at second racking, at the time of bottling and at 6 and 14 months after bottling. The total polyphenols extract (TPx) in each sample was isolated by column chromatography. The phenolic composition (anthocyanins and proanthocyanidins), in vitro antioxidant activity, and sensory property (astringency, bitterness) of the isolated TPx from different winemaking stages were evaluated through high-performance liquid chromatography-diode array detection, 1,1-diphenyl-2-picrylhidrazyl radical test, ferric reducing antioxidant power assay, total phenolic index, MWI (polyphenol molecular weight index), TSA (tannin specific activity), and sensory panel tasting. The results showed that the phenolic composition of red wine varied significantly during winemaking. The intensity of astringency (IA) and the intensity bitterness (IB) of the isolated TPx from different winemaking stages increased from 2 days of maceration until second racking and then decreased. Furthermore, MWI and TSA are positively correlated with IA and IB. The in vitro antioxidant activity of the isolated TPx from different winemaking stages maintained unchanged after alcoholic fermentation, which was independent of the variation of phenolic composition and sensory properties.

Chemical characterization and antioxidant activities of oligomeric and polymeric procyanidin fractions from grape seeds.

Two procyanidin fractions, namely oligomers and polymers isolated from grape seed methanolic extract were characterized. Phenolic composition and procyanidin purity of these fractions were determined by normal-phase and reverse-phase HPLC, thioacidolysis-HPLC, ESI-MS analyses, formaldehyde-HCl precipitation and elemental analysis. Antioxidant activities of these fractions and other well-known antioxidants were measured using xanthine-xanthine oxidase system for generating superoxide radical ({O2(-)}), the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical method and the Fenton system for generating hydroxyl radical (HO). The results showed that both oligomeric and polymeric procyanidin fractions were highly pure, with the degree of polymerization ranging from 2 to 17-18 and 12 to 32-37, respectively. On the basis of molar concentration, polymeric procyanidins appeared the highest antioxidant activities, followed by oligomeric procyanidins, whereas catechins presented a lower antioxidant activity than its oligomers and polymers. These results indicate that the antioxidant activities of grape seed procyanidins are positively related to their degree of polymerization. Moreover, grape seed procyanidins presented higher antioxidant activities than other well-known antioxidants such as vitamin C, suggesting that grape seed procyanidins might be of interest to be used as alternative antioxidants.

High-performance liquid chromatography/electrospray ionization mass spectrometric characterization of new products formed by the reaction between flavanols and malvidin 3-glucoside in the presence of acetaldehyde.

Monomer and polymer flavan-3-ols and anthocyanins are the two major groups of phenolic compounds in red wine and one of the most important reactions during red wine ageing is the condensation reaction, either direct or indirect, between these two classes of compounds. In this work, the reaction of (+)-catechin, (-)-epicatechin and dimer procyanidin B2 with malvidin 3-glucoside, in the presence of acetaldehyde, was carried out in wine model solutions at pH 1.7 and 3.2. Identification of the reaction products was carried out by high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) and MS(n) analysis. Various reaction products were detected. The structures of three condensation products - malvidin-3-glucoside-ethyl-(epi)catechin-1''-hydroxyethyl, malvidin-3-glucoside-ethyl-dimer-vinyl and malvidin-3-glucoside-ethyl-dimer-1''-hydroxyethyl - were identified in a model solution for the first time. Moreover, in the reaction solution containing dimer B2 at pH 3.2, monomer epicatechin, trimer and tetramer procyanidins were also detected indicating that, under these conditions, dimer procyanidins can either be hydrolyzed to monomers or polymerized to higher oligomer or polymers.

Modulation of MPP+ uptake by procyanidins in Caco-2 cells: involvement of oxidation/reduction reactions.

It is becoming increasingly evident that the absorption of certain nutrients and drugs and their effects are largely influenced by the concomitant ingestion of other substances. As various xeno- and endobiotics belong to the class of organic cations, the aim of this work was to study the modulation of the intestinal apical uptake of organic cations by diet procyanidins. Five procyanidin fractions with different structural complexity were obtained after fractionation of a grape seed extract. The effect of these compounds on 1-methyl-4-phenylpyridinium (MPP+) uptake was evaluated in Caco-2 cells. Apical uptake of 3H-MPP+ by Caco-2 cells was increased by a 60 min exposure to 600 microg ml(-1) of procyanidin fractions, that increase being positively related with procyanidins structural complexity. It was verified that 3H-MPP+ uptake increased with preincubation time. It was speculated that procyanidins were oxidized during preincubation, this change could interfered with transport activity. Tested oxidizing agents showed that the redox state of the transporter could affect its activity. Additionally, trans-stimulation experiments showed that catechin and fraction I (the simpler fraction) can use the same transporter as MPP+. The results are compatible with the hypothesis of these compounds being competitive inhibitors of MPP+ transport. In conclusion, procyanidins are capable to modulate MPP+ apical uptake in Caco-2 cells, this transport being most probably modulated through oxidation-reduction phenomena. Interactions between these compounds and drugs present in the diet may affect their absorption and bioavailability. Both the concentration and complexity of the procyanidin compounds should be taken into account in medical practice.