Fitoquímicos: una nueva clase de prebióticos / Phytochemicals: a new class of prebiotics

RESUMEN La microbiota intestinal (MI) es considerada como un nuevo blanco para la prevención y manejo nutricional de las alteraciones inflamatorias y metabólicas asociadas a las enfermedades crónicas no-transmisibles. Los prebióticos son principalmente fibras solubles cuyo consumo favorece el crecimiento de poblaciones bacterianas beneficiosas de la MI e impacta favorablemente la salud del consumidor. Esta revisión presenta a los fitoquímicos dietarios, que incluyen a más de 8.000 compuestos, como una nueva clase de prebióticos debido a su capacidad de estimular poblaciones de Lactobacillus, Bifidobacterium, Akkermansia y de bacterias productoras de butirato en el colon, a expensa de bacterias potencialmente dañinas como C. histolyticum. Además, los fitoquímicos son transformados por la MI en múltiples metabolitos que ejercen actividades biológicas a veces más potentes que la molécula inicial de la cual provienen. Individuos con distintos metabotipos han sido descritos de acuerdo a su capacidad de responder al consumo de isoflavonas, lignanos o elagitaninos, dependiendo de la presencia en su MI de bacterias capaces de transformar dichos polifenoles en equol, enterolactona/enterodiol y urolitinas, respectivamente, los cuales exhiben actividades biológicas. Valerolactonas y ácidos aromáticos también son producidos por la MI a través del metabolismo de las proantocianidinas. El efecto prebiótico de los fitoquímicos contribuiría a explicar los efectos saludables del consumo de frutas y verduras ricos en fitoquímicos.

ABSTRACT Intestinal microbiota (IM) is considered as a new target for the prevention and nutritional management of inflammatory and metabolic alterations associated with non-transmissible chronic diseases. Prebiotics are mainly soluble fibers whose consumption favors the growth of beneficial bacterial populations of the IM and positively impacts health. This review discusses dietary phytochemicals, which include more than 8,000 compounds, as a new class of prebiotics due to its ability to stimulate populations of Lactobacillus, Bifidobacterium, Akkermansia and butyrate producing bacteria in the colon at the expense of potentially harmful bacteria, such as C. histolyticum. In addition, phytochemicals are transformed by IM into a great array of metabolites exerting biological activities and are sometimes more potent than the initial molecule from which they are derived. Individuals with different metabotypes have been described according to their ability to respond to the consumption of isoflavones, lignans or ellagitannins, depending on the presence in their IM of bacteria capable of transforming these polyphenols into equol, enterolactone/enterodiol and urolithins, respectively, which exhibit biological activities. Valerolactones and aromatic acids are also produced by the IM through proanthocyanidin metabolism. The prebiotic effect of phytochemicals would help to explain the healthy effects associated with the consumption of fruits and vegetables rich in phytochemicals.

Polyphenolic extracts of walnut (Juglans regia) green husk containing juglone inhibit the growth of HL-60 cells and induce apoptosis

BACKGROUND: Juglone is a naphthoquinone currently obtained by chemical synthesis with biological activities including antitumor activity. Additionally, juglone is present in the green husk of walnut, which suggests evaluating the effect of GH extracts on carcinogenic cell lines. RESULTS: Walnut green husk ethanolic extract was obtained as 169.1 mg juglone/100 g Green Husk and antioxidant activity (ORAC) of 44,920 µmol Trolox Equivalent/100 g DW Green Husk. At 1 µM juglone in HL-60 cell culture, green husk extract showed an antiproliferative effect, but pure juglone did not; under these conditions, normal fibroblast cells were not affected. A dose-dependent effect on mitochondrial membrane potential loss was observed. Apoptosis of HL-60 was detected at 10 µM juglone. Despite high ORAC values, neither purified juglone nor the extract showed protective effects on HL-60 cells under oxidative conditions. CONCLUSIONS: Green husk extract generates an antiproliferative effect in HL-60 cells, which is related to an induction of the early stages of apoptosis and a loss of mitochondrial membrane potential. The normal cells were not affected when juglone is present at concentrations of 1 µM, while at higher concentrations, there is loss of viability of both cancerous and healthy cells.

High temperature and UV-C treatments affect stilbenoid accumulation and related gene expression levels in Gnetum parvifolium

Background: Gnetum parvifolium stems and roots have been used for a long time in traditional Chinese medicines. Stilbenes are bioactive compounds present in G. parvifolium plants, and they possess antioxidative and anticancer properties. However, little is known about the responses of G. parvifolium stilbene biosynthetic pathways to stress conditions. Therefore, we investigated stilbene biosynthesis, including the expression of relevant genes, in G. parvifolium exposed to high-temperature and ultraviolet-C treatments. Results: High temperatures did not influence the accumulation of total stilbenes in stems but decreased stilbene concentrations in roots at 3 h, with a subsequent restoration to control levels. In contrast, ultraviolet irradiation induced the accumulation of total stilbenes in stems but not in roots. We also observed that high temperatures inhibited the production of resveratrol and piceatannol in G. parvifolium stems and roots, whereas ultraviolet treatments initially inhibited their accumulation (up to 6 h) but induced their production at later time points. Analyses of specific genes (i.e., PAL, C4H, 4CL, STS, and CYP) revealed that their expression levels generally increased in stress-treated stems and roots, although there was some variability in the expression profiles during treatments. Conclusions: Our results indicated that high temperatures and ultraviolet irradiation differentially affect the biosynthesis of specific stilbenes in G. parvifolium stems and roots. Therefore, cultivating G. parvifolium seedlings under optimal stress conditions may increase the biosynthesis of specific stilbene compounds.

Efecto del extracto purificado rico en antocianinas del fruto del maqui (Aristotelia chilensis) en un modelo experimental de hígado graso no alcohólico / Effect of a purified anthocyanin-rich extract of maqui (Aristotelia chilensis) on experimental model of nonalcoholic fatty liver disease

Background: Non-alcoholic fatty liver disease (NAFLD) is a spectrum of hepatic lesions, ranging from benign intrahepatic lipid accumulation (steatosis) to progressive non-alcoholic steatohepatitis, in absence of other known secondary causes. Both insulin resistance and oxidative stress have been involved in NAFLD development and progression and, therefore, insulin-sensitizers and/or antioxidants have been targets of different therapeutic agents. Some natural compounds such as Aristotelia chilensis have a high content of polyphenols, which are known for their antioxidant and anti-inflammatory properties. Objective: To assess the effect of a purified anthocyanin-rich extract of maqui (Aristotelia chilensis) on experimental model of NAFLD. Methods: C57BL6 mice were separated in four experimental groups (n = 4-10) and fed a control diet (chow) or a high fat diet (HFD) with or without a purified anthocyanin-rich extract of Aristotelia chilensis (ACnE) (400 mg/kg/day diluted in drinking water). The hepatic effects of HFD were assessed measuring serum levels of glucose and aminotransferases, hepatic histology and triglycerides. Results: HFD diet induced an increase in hepatic triglycerides and histological NAFLD. Administration of ACnE did not affect serum aminotransferases, hepatic triglycerides, liver weight or histological NAFLD. Conclusion: Administration of an ACnE showed no effects on NAFLD in the HFD experimental model.

Introducción: El hígado graso no alcohólico (HGNA) constituye un espectro de lesiones hepáticas, desde la acumulación lipídica intrahepática benigna (esteatosis) hasta la esteatohepatitis no-alcohólica progresiva, en ausencia de causas secundarias conocidas. En el desarrollo y la progresión del HGNA se ha involucrado la resistencia a insulina y el estrés oxidativo y, por lo tanto, insulino-sensibilizantes y antioxidantes han sido blancos de diferentes agentes terapéuticos. Algunos compuestos naturales como la Aristotelia chilensis (maqui) tienen un alto contenido de polifenoles, los que presentan propiedades antiinflamatorias y antioxidantes. Objetivo: Evaluar el efecto de un extracto purificado rico en antocianinas (EACn) del fruto del maqui (Aristotelia chilensis) sobre la esteatosis, en un modelo experimental de HGNA. Métodos: Los ratones fueron distribuidos en 4 grupos (n = 4-10). Dos alimentados con una dieta estándar (grupo control) y dos con una dieta alta en grasa- high fat diet (grupo HFD). Un grupo control y uno HFD recibieron además 400 mg/kg/día de EACn (grupo EACn). Se determinaron los niveles séricos de aminotransferasas y glucosa; se evaluó la histología hepática y el contenido hepático de triglicéridos. Resultados: HFD indujo aumento de triglicéridos hepáticos e HGNA histológico. La administración de EACn no modificó las transaminasas séricas, los triglicéridos hepáticos, el peso del hígado ni el HGNA histológico. Conclusiones: La administración de un EACn no mostró efectos en el modelo experimental de HGNA inducido por una dieta alta en grasa.

Dinámica de polifenoles y estudio anatomo-histoquímico en Schinus longifolius (Lindl.) Speg. (Anacardiaceae) en respuesta a la infección por Calophya mammifex (Hemiptera – Calophyidae) / Dynamics of polyphenols and anatomical and histochemical study in Schinus longifolius (Lindl.) Speg. (Anacardiaceae) in response to infection by Calophya mammifex (Hemiptera - Calophyidae)

Total phenols, total tannins, proanthocyanidins, total flavonoids and total hydroxycinnamic acids of healthy leaves and galls of Schinus longifolius (Lindl.) Speg. (Anacardiaceae) infected by Calophya mammifex (Hemiptera - Calophyidae) were analized. The gall presents a qualitative and quantitative change in the polyphenols analysed, with a reduction of phenols, tannins, flavonoids and hydroxycinnamic acids and an increased content of proanthocyanidins, whose monomer yielded cyanidin after acid cleavage. An anatomical survey was performed and clusters of sclereids and an increased vascular development respect of the healthy leaf were found. An histochemical survey showed a differential expression of polyphenolic compounds in their tissues. C. mammifex could use the gall as a shelter against adverse weather conditions and predators, and also provide food with less potentially harmful compounds in the early stages of its development.

Se analizaron los fenoles totales, taninos totales, proantocianidinas, flavonoides totales y ácidos hidroxicinámicos totales de hojas sanas y agallas de Schinus longifolius (Lindl.) Speg. (Anacardiaceae) infectado por Calophya mammifex (Hemiptera - Calophyidae). La agalla presenta una variación cuali-cuantitativa de los polifenoles estudiados, con una disminución de los fenoles, taninos, flavonoides y ácidos hidroxicinámicos y un aumento en el contenido de proantocianidinas, cuyo monómero se transforma en cianidina luego del clivaje ácido. Se realizó además un análisis anatómico de la agalla donde se encontraron acúmulos de esclereidas y un mayor desarrollo vascular respecto de la hoja sana y un ensayo histoquímico que mostró una expresión diferencial de metabolitos polifenólicos en sus tejidos. C. mammifex utiliza la agalla como refugio contra las condiciones climáticas adversas y predadores y provee además de alimento con menos compuestos potencialmente perjudiciales en las etapas tempranas de su desarrollo.

Quantificação de fenóis totais presentes nas cascas de Trichillia catigua A. Juss (Meliaceae) / Quantification of total phenols present in the bark of Trichilia catigua A. Juss (Meliaceae)

Trichillia catigua A. Juss. é uma planta medicinal utilizada principalmente como estimulante, possivelmente devido à presença de fenóis. Entre os métodos utilizados para a determinação de polifenóis em matérias-primas vegetais destaca-se a análise por meio de ensaios espectrofotométricos por apresentarem boa sensibilidade, simplicidade, e ter custos mais acessíveis. O presente trabalho teve o objetivo de validar a metodologia analítica para determinação de polifenóis na casca de catuaba em pó. Utilizou-se o método de Hagerman & Butler para a quantificação dos polifenóis totais encontrando-se 7,96%. O método validado mostrou-se simples, rápido, seletivo, linear, exato, preciso, e robusto para ser executado na rotina de laboratório de controle de qualidade, constituindo uma possibilidade de análise desta planta medicinal.

Trichilia catigua A. Juss. is a medicinal plant used especially as a stimulant, possibly due to the presence of phenols. Among the methods used for the determination of polyphenols in raw plant materials is analysis through spectrophotometric assays since they have good sensitivity, are simple and more affordable. This study aimed to validate the analytical methodology for the determination of polyphenols in the bark of powder "catuaba". The method of Hagerman & Butler was employed in the quantification of total polyphenols, yielding 7.96%. The validated method has proven to be simple, rapid, selective, linear, accurate, precise and robust to be performed in the routine of a laboratory of quality control, constituting a possibility for the analysis of this medicinal plant.

Organic grape juice intake improves functional capillary density and postocclusive reactive hyperemia in triathletes

OBJECTIVE: The aim of this study was to evaluate the effect of organic grape juice intake on biochemical variables and microcirculatory parameters in triathlon athletes. INTRODUCTION: The physiological stress that is imposed by a strenuous sport, such as a triathlon, together with an insufficient amount of antioxidants in the diet may cause oxidative imbalance and endothelial dysfunction. METHODS: Ten adult male triathletes participated in this study. A venous blood sample was drawn before (baseline) and after 20 days of organic grape juice intake (300 ml/day). Serum insulin, plasma glucose and uric acid levels, the total content of polyphenols, and the erythrocyte superoxide dismutase activity were determined. The functional microcirculatory parameters (the functional capillary density, red blood cell velocity at baseline and peak levels, and time required to reach the peak red blood cell velocity during postocclusive reactive hyperemia after a one-min arterial occlusion) were evaluated using nailfold videocapillaroscopy. RESULTS: Compared with baseline levels, the peak levels of serum insulin ( p = 0.02), plasma uric acid ( p = 0.04), the functional capillary density ( p = 0.003), and the red blood cell velocity (p < 0.001) increased, whereas the plasma glucose level (p,0.001), erythrocyte superoxide dismutase activity ( p = 0.04), and time required to reach red blood cell velocity during postocclusive reactive hyperemia ( p = 0.04) decreased after organic grape juice intake. CONCLUSION: Our data showed that organic grape juice intake improved glucose homeostasis, antioxidant capacity, and microvascular function, which may be due to its high concentration of polyphenols. These results indicate that organic grape juice has a positive effect in endurance athletes.