Benjamín Alberto Rojano

Antioxidant capacity of pure compounds and complex mixtures evaluated by the ORAC-pyrogallol red assay in the presence of Triton X-100 micelles.

The protective effect of different antioxidants and complex mixtures on the consumption of pyrogallol red (PGR) induced by peroxyl radicals was studied in the absence and presence of Triton X-100 micelles. The presence of micelles decreased significantly the protection of PGR afforded by lipophilic antioxidants (β-carotene, octyl gallate), while no effect of micelles was observed for hydrophilic antioxidants such as Trolox, caffeic acid, gallic acid, and ascorbic acid. In the presence of complex mixtures a clear effect of Triton X-100 micelles was also observed in the protection afforded by wines, tea infusions, and seed extracts of Eugenia jambolana and Myrciaria cauliflora. On the other hand, no effect of micelles was observed for orange juice and pulp fruit extracts. The ORAC (Oxygen Radical Absorbance Capacity) index was evaluated in the absence (ORAC-PGR) and presence of Triton X-100 micelles (ORAC-PGRMIC). Triton X-100 micelles affect ORAC-PGR values of antioxidants in a lipophilicity-dependent way. From the obtained results, we conclude that ORAC-PGR and ORAC-PGRMIC assays could be considered as an alternative to estimate the antioxidant ability (ORAC-PGR) and to infer the association to Triton X-100 micelles (ORAC-PGR/ORAC-PGRMIC) of pure antioxidants and their complex mixtures.

Structure-activity relationship in the interaction of substituted perinaphthenones with Mycosphaerella fijiensis.

The levels of native fungitoxic perinaphthenone phytoalexins in susceptible Musa varieties (banana), which are commercially grown in large plantations, are too low to provide plants with long-lasting protection against highly pathogenic fungi. Novel strategies for plant protection are necessary to reduce crop losses and to prevent the development of resistant fungal strains. The synthesis of novel fungicides based on the structures of perinaphthenone natural products is considered to be a promising strategy. Thirteen substituted perinaphthenones, among them two known natural products (1, 2) and 11 synthetics (3-13), were evaluated for their activity against Mycosphaerella fijiensis , and their half-maximal inhibitory concentrations (IC(50)) were calculated to establish structure-activity relationships (SAR). A SAR trend was hypothesized, leading to the design of a new compound, 4-methoxy-2-nitro-1H-phenalen-1-one (14); the new compound displayed significantly enhanced in vitro activity against M. fijiensis compared to other perinaphthenone derivatives. The activity of 14 was comparable to that of two commercial fungicides.

Antioxidant Activity and Cardioprotective Effect of a Nonalcoholic Extract of Vaccinium meridionale Swartz during Ischemia-Reperfusion in Rats

Our objective was to assess the antioxidant properties and the effects against the reperfusion injury of a nonalcoholic extract obtained by fermentation from the Colombian blueberry, mortiño (Vaccinium meridionale Swartz, Ericaceae). Antioxidant properties were assessed by in vitro systems. To examine the postischemic myocardial function, isolated rat hearts were treated 10 min before ischemia and during the first 10 min of reperfusion with the extract. To analyze the participation of nitric oxide (NO), other experiments were performed in the presence of nitric oxide synthase (NOS) inhibition with NG-nitro-L-arginine methyl ester (L-NAME). In cardiac tissue thiobarbituric acid reactive substances (TBARS) concentration, reduced glutathione (GSH) content, endothelial NOS (eNOS), and Akt expression were also measured. The blueberry extract showed higher total phenols and anthocyanins contents, scavenging activity of superoxide radical and systolic and diastolic function was improved, TBARS diminished, GSH was partially preserved, and both NOS and Akt expression increased in hearts treated with the extract. These beneficial effects were lost when eNOS was inhibited. In resume, these data show that the increase of eNOS expression via Akt and the scavenging activity contribute to the cardioprotection afforded by acute treatment with Colombian blueberry extract against ischemia and reperfusion injury.

Effect of Relative Humidity on the Antioxidant Activity of Spray-Dried Banana Passion Fruit (Passiflora Mollisima Baley)-Coated Pulp: Measurement of the Thermodynamic Properties of Sorption

The antioxidant activity of the spray-dried banana passion fruit-coated pulp with maltodextrin10 DE was evaluated throughout 30 days of storage at a temperature of 25°C for different relative humidity values It was influenced by the relative humidity throughout the 30 days of storage. In addition, the sorption equilibria of water for spray-dried banana passion fruit-coated pulp with maltodextrin 10 DE at 25, 35, 45, and 55°C, over a range of relative humidity levels from 0.113 to 0.843, was determined using a gravimetric static method. The isosteric heat and Gibbs free energy were calculated from the sorption equilibrium. The Guggenheim-Anderson-Boer (GAB) and Brunauer-Emmett-Teller (BET) models were tested to fit the experimental data. The GAB model was found to be the most suitable for describing the sorption curves, exhibiting an error smaller than 10% and an r greater than 0.99. The monolayer moisture content values for the sorption at different temperatures that were calculated using the GAB model ranged between 0.05315 to 0.05716 g water/g dry matter. The sorption curves exhibited a Type III behavior. The isosteric heat decreased with increasing moisture content while the Gibbs free energy increased.

Effect of temperature on antioxidant capacity during drying process of mortiño (Vaccinium meridionale Swartz)

ABSTRACT The mortiño fruit (Vaccinium meridionale Swartz) has been recognized as an excellent source of antioxidants, phenolic compounds, and anthocyanins. Drying conditions, particularly temperature, often lead to food quality degradation. The present study investigated the influence of drying temperature (40, 50, and 60°C) on antioxidant activity, anthocyanin, and phenol content of mortiño. Four different thin layer drying models of drying kinetics (Modified page, Newton, Henderson & Pabis and, two-terms) were fitted to the experimental data. For antioxidant capacity determination, oxygen radical absorbance capacity and ferric ion reducing antioxidant power assays were used. The results showed that antioxidant capacity, and phenolic and anthocyanin content all decreased with increasing temperature and drying time. It was observed that phenols and anthocyanins were conserved in greater amounts at 60°C with 34% (5.85 mg gallic acid/g dm) and 32% (2.36 mg Cyanidin-3-glucoside/g dm) preservation of initial content, respectively. Drying kinetics models were compared based on their R2 and root mean square error values between the experimental and predicted moisture ratios. The two-terms model was found to satisfactorily describe the drying curves for all temperatures evaluated, with a determination coefficient (R2) above 0.9987 and root mean square error lower than 0.0201.

Correlation of the inhibitory activity of phospholipase A2 snake venom and the antioxidant activity of Colombian plant extracts.

Veneno de cobra continua a ser um problema importante de saude em muitos paises da America Latina. Apesar dos avancos na terapia antiveneno, os efeitos locais causados por fosfolipases A2 miotoxica (PLA2) presentes no veneno, ainda persistem. Em busca de alternativas para antagonizar a atividade da PLA2 do veneno de Bothrops asper, foram selecionados 36 extratos pertencentes a dezessete familias de plantas vasculares e briofitas. Uma inibicao significativa da atividade enzimatica de PLA2 presente no veneno de B. asper foi observada em onze extratos. Alem disso, a atividade antioxidante dos extratos foi avaliada. Os resultados evidenciaram uma correlacao estatisticamente significativa entre os extratos com acao inibitoria contra a PLA2 e aqueles com atividade antioxidante. Tambem, a quantidade de fenois foi avaliada e foi encontrada uma relacao entre a atividade biologica e a presenca dessas substâncias. Nove extratos foram testados contra uma fracao do veneno rico em PLA2 basica (Fx-V B. asper), resultando em um efeito inibitorio na atividade desta fracao da PLA2 na faixa de 30-80%. Esta atividade foi apoiada pela inibicao que esses extratos apresentaram na citotoxicidade causada pelo Fx-V B. asper sobre mioblastos C2C12 de musculo esqueletico de murino. Os resultados podem indicar a minimizacao dos esforcos na busca de inibidores da PLA2, com foco nas amostras com propriedades antioxidantes conhecidas.

A New Model for Predicting Sorption Isotherm of Water in Foods

A new model for predicting sorption isotherms of type II and III based on the Polanyi theory is proposed. This model allows the prediction of the sorption isotherms at different temperatures from one experimental isotherm. The theoretical predictions of isotherms and isosteric heat were validated successfully using data from literature for twenty one foods. This method allows total experimental time and operation costs to be reduced.

Anti-inflammatory activity of berenjenol and related compounds.

Berenjenol (1), isolated from Oxandra cf. xylopioides (Annonaceae), was tested on two different experimental models of inflammation. The compound showed anti-inflammatory activity in the test of acute mouse ear edema induced by TPA (54% inhibition, 1 micromol/ear) as well as in the test of subchronic inflammation induced by repeated application of TPA (57% inhibition, 7x1 micromol/ear). Moreover, while it reduced the expression of both COX-2 (65% inhibition at 50 microM) and iNOS (80% inhibition at 50 microM), it was not active against TNF-alpha and IL-1 beta in murine macrophages (RAW 264.7) stimulated with LPS. Structural modification of 1 gave two derivatives, berenjenol acetate (2) and 3-oxo-berenjenol (3). Of these, the latter had a high degree of activity in the acute test (66% inhibition, 1.1 micromol/ear), whereas the former showed no enhanced pharmacological properties. Interestingly, the original compound exhibited higher activity than either of its derivatives in the subchronic model. We thus concluded that whereas 3-oxidation of 1 (compound 3), but not 3-acetylation (2), increases the activity in the acute model of inflammation, structural modification of 1 does not enhance the compounds effects in the subchronic model.

Effect of Seminal Plasma Components on the Quality of Fresh and Cryopreserved Stallion Semen

Abstract The importance of seminal plasma (SP) components for stallion semen quality and freezability is little known. This study aimed to evaluate the relationship between SP components and fresh/cryopreserved stallion semen quality. Semen of 30 stallions was collected, and then, SP was recovered and lyophilized. Total protein (TP), vitamin C (CVIT), vitamin E (EVIT), vitamin A (AVIT), iron (Fe), copper (Cu), magnesium, and zinc (Zn) in SP were assessed. Sperm was frozen in an extender supplemented with lyophilized SP. In fresh semen motility, abnormal morphology (AM), sperm vitality (SV), and plasma membrane integrity (PMI) were evaluated. In post‐thaw semen, additionally, total motility (TM), progressive motility (PM), straight line velocity (VSL), curvilinear velocity (VCL), average path velocity (VAP), amplitude of lateral head displacement (ALH), and beat cross‐frequency (BCF) were assessed. Levels of component of SP were established by a distribution analysis. Generalized linear models were fitted. Comparisons of means were done with Tukeys test. Correlation and regression analyses were performed. Vitamins and ions were found to be related to fresh semen quality. For post‐thaw sperm, medium TP showed higher semen quality. Negative regression and correlation coefficients between CVIT and all post‐thaw semen parameters were found. Low EVIT yielded the lowest PM, VSL, and VAP values, while a high level of AVIT yielded the best results for sperm quality. A high level of Cu yielded higher results for TM, PM, VCL, and ALH. Moreover, a negative correlation was found between Zn, SV, and PMI. In conclusion, SP composition influences fresh and post‐thaw stallion semen quality. HighlightsComposition of seminal plasma (SP) influences the fresh semen quality of stallion.High levels of vitamin E and ions in SP had higher sperm integrity.Composition of supplemented SP is determinant in thawed sperm quality.A high level of vitamin C alters post‐thaw semen quality parameters.

Polifenoles y Actividad Antioxidante del Fruto de Guayaba Agria (Psidium araca)

The content of polyphenol compounds such as total phenols, total flavonoids, condensed tannins and phenolic acids of the sour guava fruits (Psidium araca) was determined. These compounds determine the antioxidant capacity, property that expresses the facility for scavenging reactive oxygen species as nutraceutical value of the specie. The antioxidant activity of sour guava was determined by different methods such as DPPH, ABTS, FRAP and ORAC. The results are comparable with those found for common guava (Psidium guajava) and higher than those reported for common fruits such as pineapple, watermelon, passion fruit and melon. In conclusion, sour guava is a fruit with antioxidant potential, which can be handled by various technological methods to get high added-value products.