Analysis of the toxicological and pharmacokinetic profile of Kaempferol-3-O-β-D-(6"-E-p-coumaryl) glucopyranoside - Tiliroside: in silico, in vitro and ex vivo assay / Análise do perfil toxicológico e farmacocinético de Kaempferol-3-O-β D-(6"-E-p-cumaril) glucopiranosídeo - Tilirosídeo: ensaio in silico, in vitro e ex vivo

Tiliroside is a glycosidic flavonoid present in many plants species including Helicteres velutina K. Schum (Malvaceae sensu lato), commonly known in Brazil as "pitó". This molecule has been shown to have many biological activities, however no study has been carried out to investigate the toxicity of this substance. The present work aimed to evaluate the possible cellular toxicity in silico, in vitro and ex-vivo of the kaempferol-3-O-β-D-(6”-E-p-coumaroyl) glucopyranoside (tiliroside), through chemical structure analysis, toxicity assessment and predictive bioactive properties, using human samples for in vitro and ex-vivo tests. The in silico analysis suggests that tiliroside exhibited great absorption index when penetrating biological membranes. In addition, it also displayed considerable potential for cellular protection against free radicals, and anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and antithrombotic activities. The assessment of the hemolytic and genotoxic effects of tiliroside showed low hemolysis rates in red blood cells and absence of cellular toxicity in the oral mucosa cells. The data obtained indicate that this molecule could be a promising therapeutic approach as a possible new drug with biotechnological potential.(AU)

O tilirosídeo é um flavonóide glicosídico presente em muitas espécies de plantas, incluindo Helicteres velutina K. Schum (Malvaceae sensu lato), conhecida no Brasil como “pitó”. Esta molécula mostrou ter muitas atividades biológicas, porém nenhum estudo foi realizado para investigar a toxicidade dessa substância. O presente trabalho teve como objetivo avaliar a possível toxicidade celular in silico, in vitro e ex-vivo do kaempferol-3-O-β-D- (6 ”-Ep-coumaroil) glucopiranosídeo (tilirosídeo), por meio de análises de estrutura química, toxicidade avaliação e propriedades bioativas preditivas, utilizando amostras humanas para testes in vitro e ex-vivo. A análise in silico sugere que o tilirosídeo exibe bom índice de absorção para penetrar nas membranas biológicas. Além disso, apresentou considerável potencial de proteção celular contra os radicais livres e com atividades anticarcinogênica, antioxidante, antineoplásica, antiinflamatória, anti-hemorrágica e antitrombótica. A avaliação dos efeitos hemolíticos e genotóxicos do tilirosídeo mostrou baixas taxas de hemólise nas hemácias e ausência de toxicidade em células da mucosa oral. Os dados obtidos indicam que esta molécula pode possuir uma abordagem terapêutica promissora como uma possível nova droga com potencial biotecnológico.(AU)

Analysis of the toxicological and pharmacokinetic profile of Kaempferol-3-O-β-D-(6"-E-p-coumaryl) glucopyranoside - Tiliroside: in silico, in vitro and ex vivo assay / Análise do perfil toxicológico e farmacocinético de Kaempferol-3-O-β D-(6"-E-p-cumaril) glucopiranosídeo - Tilirosídeo: ensaio in silico, in vitro e ex vivo

Tiliroside is a glycosidic flavonoid present in many plants species including Helicteres velutina K. Schum (Malvaceae sensu lato), commonly known in Brazil as "pitó". This molecule has been shown to have many biological activities, however no study has been carried out to investigate the toxicity of this substance. The present work aimed to evaluate the possible cellular toxicity in silico, in vitro and ex-vivo of the kaempferol-3-O-β-D-(6”-E-p-coumaroyl) glucopyranoside (tiliroside), through chemical structure analysis, toxicity assessment and predictive bioactive properties, using human samples for in vitro and ex-vivo tests. The in silico analysis suggests that tiliroside exhibited great absorption index when penetrating biological membranes. In addition, it also displayed considerable potential for cellular protection against free radicals, and anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and antithrombotic activities. The assessment of the hemolytic and genotoxic effects of tiliroside showed low hemolysis rates in red blood cells and absence of cellular toxicity in the oral mucosa cells. The data obtained indicate that this molecule could be a promising therapeutic approach as a possible new drug with biotechnological potential.

O tilirosídeo é um flavonóide glicosídico presente em muitas espécies de plantas, incluindo Helicteres velutina K. Schum (Malvaceae sensu lato), conhecida no Brasil como “pitó”. Esta molécula mostrou ter muitas atividades biológicas, porém nenhum estudo foi realizado para investigar a toxicidade dessa substância. O presente trabalho teve como objetivo avaliar a possível toxicidade celular in silico, in vitro e ex-vivo do kaempferol-3-O-β-D- (6 ”-Ep-coumaroil) glucopiranosídeo (tilirosídeo), por meio de análises de estrutura química, toxicidade avaliação e propriedades bioativas preditivas, utilizando amostras humanas para testes in vitro e ex-vivo. A análise in silico sugere que o tilirosídeo exibe bom índice de absorção para penetrar nas membranas biológicas. Além disso, apresentou considerável potencial de proteção celular contra os radicais livres e com atividades anticarcinogênica, antioxidante, antineoplásica, antiinflamatória, anti-hemorrágica e antitrombótica. A avaliação dos efeitos hemolíticos e genotóxicos do tilirosídeo mostrou baixas taxas de hemólise nas hemácias e ausência de toxicidade em células da mucosa oral. Os dados obtidos indicam que esta molécula pode possuir uma abordagem terapêutica promissora como uma possível nova droga com potencial biotecnológico.

Pharmacokinetics and metabolism of cinnamic acid derivatives and flavonoids after oral administration of Brazilian green propolis in humans.

Brazilian green propolis (BGP) has chemical compounds from botanical origin that are mainly cinnamic acid derivatives (artepillin C, baccharin, and drupanin) and flavonoids (kaempferide and 6-methoxykaempferide). These compounds are expected to play an important role in the pharmacological activities of BGP. However, there is little known about the pharmacokinetics and metabolism of these compounds after oral administration of BGP. The aim of this study is to investigate the pharmacokinetics and metabolism of BGP components in humans. Twelve volunteers received 3 capsules containing 360 mg of BGP ethanol extract powder. Plasma samples were collected before and up to 24 h after the intake of BGP capsules. The collected plasma samples with or without hydrolysis by the deconjugating enzyme were analyzed by LC/MS/MS. After enzymatic hydrolysis, the Cmax values of artepillin C and drupanin, which were detected mainly in plasma after ingestion of BGP capsules, were 1255 ± 517 and 2893 ± 711 nM, respectively, of which 89.3% and 88.2% were found to be the phenolic glucuronide conjugate. This is the first time that the pharmacokinetics of the BGP components of human metabolites have been reported. Our results could provide useful information for the design and interpretation of studies to investigate the mechanisms and pharmacological effects of BGP.

Chrysin Modulates Genes Related to Inflammation, Tissue Remodeling, and Cell Proliferation in the Gastric Ulcer Healing.

Chrysin exhibits anti-inflammatory and antioxidant activities. Here, the gastroprotective effect of chrysin was investigated in mouse models of gastric ulcer induced by absolute ethanol, acetic acid, and ischemia-reperfusion injury. The gastric-healing effect was evaluated at 7 and 14 days after treatment; the mechanism of action was verified using the expression of metalloproteinase 2 (MMP-2) and 9 (MMP-9), caspase-3, cyclooxygenase 1 (COX-1) and 2 (COX-2), epidermal growth factor (EGF), and interleukin-10. Chrysin (10 mg/kg) inhibited macroscopic lesions and increased catalase activity in the mouse model established using absolute ethanol. It ameliorated the gastric ulcer caused by acetic acid by improving the expression of inflammatory genes such as COX-2, inhibiting negative remodeling promoted by MMP-9, increasing cell proliferation effect via EGF, and reducing cellular apoptosis by modulating caspase-3. A faster healing effect was evident in the first 7 days of treatment compared to 14 days of treatment, indicating the pharmacological potential of chrysin. Overall, these results demonstrate the potent effect of chrysin in the gastrointestinal tract and elucidate the genes involved in the healing of gastric ulcers. Moreover, an increase in the levels of gastric mucosa defensive factors is involved in the activity of chrysin in the gastric mucosa.

In vitro antifungal activity and phytochemical characterization of Eugenia uniflora, Libidibia ferrea and Psidium guajava

The aim of this study was evaluate the in vitro antifungal activity of crude extracts from Eugenia uniflora, Libidibia ferrea and Psidium guajava. The extracts were obtained by turbo-extraction using water (AQ) or acetone-water (AC-W) (7:3, v/v) as solvents and lyophilized to obtain the crude extracts (CE). The CE were characterized by UV-Vis, TLC and HPLC. The activity of CEs was investigated against clinical isolates of Candida spp. and the Minimum Inhibitory Concentration (MIC), MIC50 and MIC90 were determinated. The analysis by TLC showed that all CEs presented polyphenols (flavonoids and tannins). The CEs from E. uniflora showed higher amount of polyphenols (30.35 ± 2.15%, AC-W) and the HPLC analysis revealed the tannins in all extracts. The CEs of E. uniflora showed MIC range from 1.9 to 500.0 µg/mL, and lower values of MIC50 and MIC90 against non-albicans Candida isolates. Regarding L. ferrea and P. guajava, the results showing MIC from 3.9 to 1000.0 µg/mL (CE-AQ) against C. albicans. The results demonstrate antifungal performance from CE against various species of Candida spp., suggesting that the herbal species may be use as new potential antifungal agents. Additionally, the polyphenol content can play a pivotal role in the antifungal properties of CE.

Chemical Composition and In Vitro Bioaccessibility of Antioxidant Phytochemicals from Selected Edible Nuts.

The ultimate health benefits of peanuts and tree nuts partially depend on the effective gastrointestinal delivery of their phytochemicals. The chemical composition and in vitro bioaccessibility of tocopherols, tocotrienols and phenolic compounds from peanuts and seven tree nuts were evaluated by analytical and chemometric methods. Total fat and dietary fiber (g 100 g-1) ranged from 34.2 (Emory oak acorn) to 72.5 (pink pine nut; PPN) and from 1.2 (PPN) to 22.5 (pistachio). Samples were rich in oleic and linoleic acids (56-87 g 100 g-1 oil). Tocopherols and tocotrienols (mg·kg-1) ranged from 48.1 (peanut) to 156.3 (almond) and 0 (almond, pecan) to 22.1 (PPN) and hydrophilic phenolics from 533 (PPN) to 12,896 (Emory oak acorn); flavonoids and condensed tannins (mg CE.100 g-1) ranged from 142 (white pine nut) to 1833 (Emory oak acorn) and 14 (PPN) to 460 (Emory oak acorn). Three principal components explained 90% of the variance associated with the diversity of antioxidant phytochemicals in samples. In vitro bioaccessibility of tocopherols, tocotrienols, hydrophilic phenolics, flavonoids, and condensed tannins ranged from 11-51%, 16-79%, 25-55%, 0-100%, and 0-94%, respectively. Multiple regression analyses revealed a potential influence of dietary fiber, fats and/or unsaturated fatty acids on phytochemical bioaccessibility, in a structure-specific manner.

Effect of simulated gastrointestinal digestion on polyphenols and bioactivity of the native Chilean red strawberry (Fragaria chiloensis ssp. chiloensis f. patagonica).

The native Chilean red strawberry (Fragaria chiloensis spp. chiloensis f. patagonica) is a wild strawberry with high polyphenol content and antioxidant activity originating in central-southern Chile. The aim of the present work was to compare the composition and bioactivity of polyphenol-concentrated extracts (PCE) of the fruit, before and after simulated gastrointestinal digestion (GID). Twenty nine compounds were tentatively identified in the non-digested PCE. After GID, 26 and 23 compounds were detected, in the gastric and intestinal steps, respectively. The compounds that were more affected by the simulated GID were cyanidin hexoside, bis hexahydroxydiphenic acid (HHDP) hexosides, bis HHDP galloyl hexosides, apigenin hexoside, and quercetin dihexoside. Results show a decrease in the total phenolic content by 3.4% and 43% at the end of the gastric and intestinal steps, respectively. In the same way, the total flavonoid content decreased by 60.4% and 90.9% at the end of the gastric and intestinal step, respectively. Overall, the antioxidant activity decreased during the gastrointestinal process; as well as the inhibitory activity against α-glucosidase and lipase was reduced by the simulated digestion. These results are a first approach to understand the effects induced by the gastrointestinal digestion on the bioactivity and polyphenolic profile of this native fruit.

Development of morin/hydroxypropyl-ß-cyclodextrin inclusion complex: Enhancement of bioavailability, antihyperalgesic and anti-inflammatory effects.

Morin is a flavonoid has been reported with several pharmacological effects such as, antioxidant, anti-inflammatory, anticancer, antidiabetic, etc. However, morin has low solubility in water, which decreases the bioavailability and limits its clinical application. In this way, to improve the pharmaceutical properties, morin was complexed in hydroxypropyl-ß-cyclodextrin (HP-ß-CD) and its oral bioavailability and anti-inflammatory effects were evaluated. Initially, a phase solubility study was performed, which showed that HP-ß-CD would be the better cyclodextrin for the formation of complexes with morin. The morin/HP-ß-CD inclusion complex (1:1) was prepared by freeze-drying method. The sample obtained was characterized by DSC, FTIR, PXRD, SEM and 1H NMR techniques, evidencing the formation of morin/HP-ß-CD inclusion complex. In addition, complexation efficiency (98.3%) and loading content (17.63%), determined by HPLC demonstrated that morin was efficiently complexed in HP-ß-CD. In vitro dissolution study confirmed that morin/HP-ß-CD inclusion complex increased the solubility and dissolution rate of morin. The oral bioavailability of the morin/HP-ß-CD complex and free morin were evaluated through a pharmacokinetic study in rat plasma. The oral bioavailability of morin complexed with HP-ß-CD was increased by 4.20 times compared with the free morin. Hyperalgesia induced by carrageenan and carrageenan-induced pleurisy were carried out in mice to evaluate the antihyperalgesic and anti-inflammatory activities of free morin and inclusion complex. Morin/HP-ß-CD inclusion complex showed antihyperalgesic effect in inflammatory pain model and anti-inflammatory effect decreasing leukocyte migration and TNF-α levels at a lower dose than free morin. Therefore, the morin/HP-ß-CD inclusion complex improved the solubility, dissolution rate, oral bioavailability, antihyperalgesic and anti-inflammatory effects of morin. In this way, the morin/HP-ß-CD inclusion complex exhibits potential for development of new pharmaceutical product for future clinical applications.

Simulated Gastrointestinal Digestion, Bioaccessibility and Antioxidant Capacity of Polyphenols from Red Chiltepin (Capsicum annuum L. Var. glabriusculum) Grown in Northwest Mexico.

Chiltepin, a wild chili mostly used in different traditional foods and traditional medicine in Northwest Mexico, represents a source of polyphenols. However, studies about the bioaccessibility of polyphenols as a parameter to measure the nutritional quality and bioefficacy of them in the fruit after consumption are scarce. Chiltepin showed phenolic acids and flavonoids contents between 387 and 65 µg/g, respectively. Nevertheless, these values decreased after the digestion process. Before digestion, gallic acid, 4-hydroxibenzoinc acid, chlorogenic acid, caffeic acid, p-coumaric acid, quercetin and luteolin were the main polyphenols found in chiltepin by HPLC-DAD and confirmed by FIA-ESI-IT-MS/MS. Gallic and chlorogenic acids were non-detected in the gastric phase, while only p-coumaric acid (5.35 ± 3.89 µg/g), quercetin (5.91 ± 0.92 µg/g) and luteolin (2.86 ± 0.62 µg/g) were found in the intestinal phase. The bioaccessibility of phenolic acids, flavonoids, and total polyphenols after the intestinal phase was around 24, 17 and 23%, respectively. Overall, results indicated that release of polyphenols from chiltepin fruit might be affected by the food matrix and gastrointestinal conditions due to the low bioaccessibility values observed.

Polyphenols from Root, Tubercles and Grains Cropped in Brazil: Chemical and Nutritional Characterization and Their Effects on Human Health and Diseases.

Throughout evolution, plants have developed the ability to produce secondary phenolic metabolites, which are important for their interactions with the environment, reproductive strategies and defense mechanisms. These (poly)phenolic compounds are a heterogeneous group of natural antioxidants found in vegetables, cereals and leguminous that exert beneficial and protective actions on human health, playing roles such as enzymatic reaction inhibitors and cofactors, toxic chemicals scavengers and biochemical reaction substrates, increasing the absorption of essential nutrients and selectively inhibiting deleterious intestinal bacteria. Polyphenols present in some commodity grains, such as soy and cocoa beans, as well as in other vegetables considered security foods for developing countries, including cassava, taro and beetroot, all of them cropped in Brazil, have been identified and quantified in order to point out their bioavailability and the adequate dietary intake to promote health. The effects of the flavonoid and non-flavonoid compounds present in these vegetables, their metabolism and their effects on preventing chronic and degenerative disorders like cancers, diabetes, osteoporosis, cardiovascular and neurological diseases are herein discussed based on recent epidemiological studies.

The application of HPLC ESI MS in the investigation of the flavonoids and flavonoid glycosides of a Caribbean Lamiaceae plant with potential for bioaccumulation.

As part of an exchange technology program between the government of Barbados and Environment Canada, methanolic and aqueous extracts from the flavonoid-rich Lamiaceae family were characterized using negative-ion electrospray mass spectrometry. The species investigated is part of the Caribbean Pharmacopoeia, and is used for a variety of health issues, including colds, flu, diabetes, and hypertension. The extracts were investigated for structural elucidation of phenolics, identification of chemical taxonomic profile, and evidence of bio-accumulator potential. The methanolic and aqueous leaf extracts of Plectranthus amboinicus yielded rosmarinic acid, ladanein, cirsimaritin, and other methoxylated flavonoids. This genus also shows a tendency to form conjugates with monosaccharides, including glucose, galactose, and rhamnose. The aqueous extract yielded four isomeric rhamnosides. The formation of conjugates by Plectranthus amboinicus is thus evidence of high bioaccumulator significance.

Pharmacokinetic evaluation of avicularin using a model-based development approach.

The aim of this study was to use the pharmacokinetic information of avicularin in rats to project a dose for humans using allometric scaling. A highly sensitive and specific bioanalytical assay to determine avicularin concentrations in the plasma was developed and validated for UPLC-MS/MS. The plasma protein binding of avicularin in rat plasma determined by the ultrafiltration method was 64%. The pharmacokinetics of avicularin in nine rats was studied following an intravenous bolus administration of 1 mg/kg and was found to be best described by a two-compartment model using a nonlinear mixed effects modeling approach. The pharmacokinetic parameters were allometrically scaled by body weight and centered to the median rat weight of 0.23 kg, with the power coefficient fixed at 0.75 for clearance and 1 for volume parameters. Avicularin was rapidly eliminated from the systemic circulation within 1 h post-dose, and the avicularin pharmacokinetic was linear up to 5 mg/kg based on exposure comparison to literature data for a 5-mg/kg single dose in rats. Using allometric scaling and Monte Carlo simulation approaches, the rat doses of 1 and 5 mg/kg correspond to the human equivalent doses of 30 and 150 mg, respectively, to achieve comparable plasma avicularin concentrations in humans.

Simultaneous quantification of flavonoids from Achyrocline satureioides by a polar-reversed phase LC method--application to skin permeation/retention studies.

A selective and sensitive polar-reversed phase LC method was validated for simultaneous quantification of the main Achyrocline satureioides flavonoids (quercetin, luteolin, and 3-O-methylquercetin) in skin samples after permeation/retention studies from topical nanoemulsions. The method was linear in a range of 0.25 to 10.0 microg/mL exhibiting a coefficient of determination higher than 0.999 for all flavonoids. No interference of the nanoemulsion excipients or skin components was observed in the retention times of all flavonoids. The R.S.D. values for intra- and inter-day precision experiments were lower than 6.73%. Flavonoids recovery from nanoemulsions and skin matrices was between 90.05 and 109.88%. In a permeation/retention study with porcine ear high amount of 3-O-methylquercetin was found in the skin sample (0.92 +/- 0.22 microg/g) after two hours. The proposed method was suitable to quantify the main flavonoids of A. satureioides in skin permeation/retention studies from topical nanoemulsions.

Efecto antiinflamatorio y antioxidante de los flavonoides de las hojas de Jungia rugosa Less (matico de puna) en un modelo experimental en ratas / Antiinflammatory and antioxidant effects of Jungia rugosa Less (matico de puna) leaves' flavonoids in rats

Objetivos: Evaluar la actividad antiinflamatoria y antioxidante de la fracción flavónica extraída de las hojas de Jungia rugosa Less. Diseño: Experimental. Lugar: Facultades de Medicina y Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú. Material biológico: Fracción flavónica extraído de las hojas de Jungia rugosa Less y ratas. Intervenciones: Las hojas de Jungia rugosa Less fueron recolectadas en el cerro Condorcunca, a 3 500 msnm, distrito de Quinua, departamento de Ayacucho. La actividad antiinflamatoria fue evaluada in vivo usando el método de edema plantar inducido por carragenina y en sangre se cuantificó los niveles séricos de interleuquinas 1, 6 y proteína C reactiva (PCR); también, se indujo el granuloma, según Sedwicks, evaluándose por histopatología. La actividad antioxidante fue evaluada in vitro mediante la neutralización del radical 1,1-difenil-2-picril-hidrazilo (DPPH). Principales medidas de resultados: Actividad antiinflamatoria y antioxidante. Resultados: La inflamación disminuyó en 43,8 por ciento, y los niveles de interleuquinas 1, 6 y PCR lo fueron en 80 por ciento, 90 por ciento y 78 por ciento, respectivamente, al ser comparados con el control (p<0,05), siendo el efecto dosis dependiente, y brindó un 97,7 por ciento de inhibición de radicales DPPH. Conclusión: Se ha demostrado que la fracción flavónica extraída de las hojas de Jungia rugosa Less es antiinflamatoria y antioxidante.

Objectives: To determine anti-inflammatory and antioxidant activities of Jungia rugosa Less leaves flavonesÆ fraction. Design: Experimental. Setting: Faculties of Medicine and Pharmacy and Biochemistry, National University of San Marcos, Lima, Peru. Biological material: Flavones fraction extracted from Jungia rugosa Less leaves and rats. Interventions: Jungia rugosa Less leaves collected in CondorcuncaÆs hill at 3 500 m.a.s.l., Quinua district, Ayacucho department. The anti-inflammatory activity was assessed in vivo in carrageenan-induced paw edema model and 1, 6 interleukins serum levels and C reactive protein (CRP) were measured in blood; granuloma was induced according to Sedwicks and studied by histopathology. The antioxidant effect was investigated in vitro by 1,1- diphenyl-2-picrylhydrazyl (DPPH) radical neutralization. Main outcome measures: Anti-inflammatory and antioxidant effects. Results: Inflammation reduced in 43,8 per cent and 1,6 interleukins and CRP levels decreased respectively 80 per cent, 90 per cent and 78 per cent compared to control, in dose-dependent effect (p<0,05), with 97,7 per cent DPPH radicals inhibition. Conclusions: Flavones fraction extracted from Jungia rugosa Less leaves is anti-inflammatory and antioxidant.

El consumo de manzanas contribuye a prevenir el desarrollo de enfermedades cardiovasculares y cáncer: antecedentes epidemiológicos y mecanismos de acción / Apple consumption helps to prevent cardiovascular diseases and cancer: epidemiology and mode of action

Consumption of fruit and vegetables has the potential to reduce non-transmissible diseases (NTD), such as cardiovascular diseases (CVD) and cancer, which are major public health concerns. Chile is a major apple producer and exporter in the world. Its production is concentrated in the sixth (O'Higgins) and seventh (Maule) regions of Central Chile. Phenolics and flavonoids are responsible for apple's high antioxidant activity. Many epidemiologic studies have shown that a diet rich in apples can reduce cardiovascular events (myocardial infarct and stroke) and some type of cancers. The mechanisms involved are not well understood. Nevertheless, antioxidants are key-players. Some of their in-vitro activities are inhibition of low-density lipoprotein (LDL) oxidation, cholesterol levels reduction, endothelium protection, reduction of neoplastic cells proliferation and apoptosis activation. Consequently, daily apple consumption campaigns in the country should be implemented, as well as funding research focused on molecular mechanisms involved in its antioxidant activity.

Las enfermedades no transmisibles (ENT), especialmente las cardiovasculares (ECV) y el cáncer, representan un grave problema de salud pública. Es conocido que el consumo de frutas y hortalizas disminuye el riesgo de sufrir dichas enfermedades. El manzano (Malus domestica Borkh.) se cultiva en Chile en una amplia zona geográfica, concentrándose principalmente en las regiones sexta y séptima. La actividad antioxidante de la manzana se debe principalmente a su contenido en fenoles y flavonoides. Varios estudios epidemiológicos han mostrado que el consumo de manzanas puede prevenir el desarrollo de ECV (infarto agudo de miocardio y enfermedad cerebro vascular) y ciertos tipos de cáncer. Los mecanismos por los cuales se producen dichos efectos, no están totalmente aclarados, sin embargo la participación de los antioxidantes es fundamental. Entre los principales hallazgos se han descrito, en relación a ECV: inhibición de la oxidación de low-density lipoprotein (LDL), disminución de colesterol total y protección de endotelio; y en relación a cáncer: disminución de la proliferación de células neoplásicas y activación de la apoptosis de las mismas. Debido al incuestionable efecto protector para la salud humana que presenta la ingesta de manzana, se deben impulsar estrategias que apunten a incentivar su consumo diario en el país. Asimismo, se deben seguir estudiando los principios activos y los mecanismos moleculares.

Flavonoids: prospective drug candidates.

The purpose of this review is to discuss the recent developments related to the chemistry and medicinal properties of flavonoids. Major flavonoids that show well categorized structures and well defined structure function-relationships are: flavans, flavanones, flavones, flavanonols, flavonols, catechins, anthocyanidins and isoflavone. The biological properties of flavonoids include antioxidant, anti-inflamatory, antitumoral, antiviral and antibacterial, as well as a direct cytoprotective effect on coronary and vascular systems, the pancreas and the liver. These characteristics place them among the most attractive natural substances available to enrich the current therapy options.

Permeability profile estimation of flavonoids and other phenolic compounds by biopartitioning micellar capillary chromatography.

This paper points out the usefulness of biopartitioning micellar chromatography (BMC) using capillary columns as a high-throughput primary screening tool providing key information about the oral absorption, skin permeability, and brain-blood distribution coefficients of 15 polyphenols (6 flavones, 2 flavonols, a flavanone, 2 flavan-3-ols, 3 phenolic acids, and a phloroglucinol) in a simple and economical way. For the compounds studied, except vicenin-2, rutin, chlorogenic acid, p-hydroxycinnamic acid, and 4-hydroxybenzoic acid, maximal oral absorption (>90%) can be expected, if there are not solubility problems or metabolic processes. On the other hand, the most retained compounds in BMC, that is, 5-hydroxyflavone, flavone, and flavanone, show the highest brain-blood distribution coefficients and skin permeability coefficients.

Constituents of the Argentinian medicinal plant Baccharis grisebachii and their antimicrobial activity.

The resinous exudate of Baccharis grisebachii which is used to treat ulcers, burns, and skin sores in Argentina showed activity towards dermatophytes and bacteria. Two diterpenes, eight p-coumaric acid derivatives, and two flavones were isolated from the exudate and the structures elucidated by spectroscopic methods. 3-Prenyl-p-coumaric acid and 3,5-diprenyl-p-coumaric acid were active towards Epidermophyton floccosum and Trichophyton rubrum with MICs of 50 and 100-125 microg/ml, respectively. The diterpene labda-7,13E-dien-2beta,15-diol was active towards Epidermophyton floccosum and Trichophyton rubrum with MICs of 12.5 microg/ml while the MIC against Microsporum canis and Trichophyton mentagrophytes was 25 microg/ml. The diterpene was also active towards Microsporum gypseum with a MIC of 50 microg/ml, and showed inhibition in both Staphylococcus aureus (methicilline resistant and sensible strains) with MICs of 125 microg/ml. The results support the use of Baccharis grisebachii in Argentinian traditional medicine.

Biotransformation of natural and synthetic isoflavonoids by two recombinant microbial enzymes.

Isolation and synthesis of isoflavonoids has become a frequent endeavor, due to their interesting biological activities. The introduction of hydroxyl groups into isoflavonoids by the use of enzymes represents an attractive alternative to conventional chemical synthesis. In this study, the capabilities of biphenyl-2,3-dioxygenase (BphA) and biphenyl-2,3-dihydrodiol 2,3-dehydrogenase (BphB) of Burkholderia sp. strain LB400 to biotransform 14 isoflavonoids synthesized in the laboratory were investigated by using recombinant Escherichia coli strains containing plasmid vectors expressing the bphA1A2A3A4 or bphA1A2A3A4B genes of strain LB400. The use of BphA and BphB allowed us to biotransform 7-hydroxy-8-methylisoflavone and 7-hydroxyisoflavone into 7,2',3'-trihydroxy-8-methylisoflavone and 7,3',4'-trihydroxyisoflavone, respectively. The compound 2'-fluoro-7-hydroxy-8-methylisoflavone was dihydroxylated by BphA at ortho-fluorinated and meta positions of ring B, with concomitant dehalogenation leading to 7,2',3',-trihydroxy-8-methylisoflavone. Daidzein (7,4'-dihydroxyisoflavone) was biotransformed by BphA, generating 7,2',4'-trihydroxyisoflavone after dehydration. Biotransformation products were analyzed by gas chromatography-mass spectrometry and nuclear magnetic resonance techniques.