Differential effects of resveratrol and its naturally occurring methylether analogs on cell cycle and apoptosis in human androgen‐responsive LNCaP cancer cells

Stilbenes are phytoalexins that become activated when plants are stressed. These compounds exist in foods and are widely consumed. Resveratrol is a grape‐derived stilbene, which possesses a wide range of health‐promoting activities, including anticancer properties. Several other stilbenes structurally similar to resveratrol are also available in food, but their biological activities remain largely unknown. In this study, we compared the effects of resveratrol and its natural derivatives pterostilbene, trans‐resveratrol trimethylether, trans‐pinostilbene and trans‐desoxyrhapontigenin on androgen‐responsive human prostate cancer LNCaP cells. We found that these compounds exert differential effects on LNCaP cell growth, cell cycle and apoptosis. Trans‐resveratrol trimethylether appeared to be the most potent compound among the stilbenes tested. Treatment of LNCaP cells with trans‐resveratrol trimethylether resulted in G2/M blockage while other compounds, including resveratrol, induced G1/S arrest. Moreover, different from other compounds, trans‐resveratrol trimethylether induced apoptosis. At the molecular level, the effects of these compounds on cell cycle correlated with induction of the cyclin‐dependent kinase inhibitor 1A and B mRNA levels. Additionally, these compounds also inhibited both androgen‐ as well as estrogen‐mediated pathways. These results provide mechanistic information on how resveratrol and its methylether analogs may act to contribute to potential antiprostate cancer activity.     

Omega‐3 Fatty Acid Profile of Eggs from Laying Hens Fed Diets Supplemented with Chia,Fish Oil,and Flaxseed

The aim of this study was to investigate the effect of diets supplemented with fish oil, flaxseed, and chia seed on the omega‐3 fatty acid composition and sensory properties of hens’ eggs. No significant difference in yolk fat content was found between treatments. The fatty acid composition of egg yolk was significantly affected by the dietary treatments. Inclusion of chia at 300 g/kg into the diet produced eggs with the highest concentration of omega‐3 fatty acid. Eicosapentaenoic acid and docosahexaenoic acid were only detected in eggs from laying hens fed the diet supplemented with fish oil. Diet had a significant effect on color, flavor and overall acceptability of eggs. Types and levels of omega‐3 fatty acids in feed influence the level of yolk omega‐3 fatty acids in egg yolk. Inclusion of chia into the hens’ diet significantly increased the concentration of yolk omega‐3 fatty acid without significant change in sensory properties.     

Comparison of five in vitro digestion models to study the bioaccessibility of soil contaminants

Soil ingestion can be a major exposure route for humans to many immobile soil contaminants. Exposure to soil contaminants can be overestimated if oral bioavailability is not taken into account. Several in vitro digestion models simulating the human gastrointestinal tract have been developed to assess mobilization of contaminants from soil during digestion, i.e., bioaccessibility. Bioaccessibility is a crucial step in controlling the oral bioavailability for soil contaminants. To what extent in vitro determination of bioaccessibility is method dependent has, until now, not been studied. This paper describes a multi-laboratory comparison and evaluation of five in vitro digestion models. Their experimental design and the results of a round robin evaluation of three soils, each contaminated with arsenic, cadmium, and lead, are presented and discussed. A wide range of bioaccessibility values were found for the three soils: for As 6-95%, 1-19%, and 10-59%; for Cd 7-92%, 5-92%, and 6-99%; and for Pb 4-91%, 1-56%, and 3-90%. Bioaccessibility in many cases is less than 50%, indicating that a reduction of bioavailability can have implications for health risk assessment. Although the experimental designs of the different digestion systems are distinct, the main differences in test results of bioaccessibility can be explained on the basis of the applied gastric pH. High values are typically observed for a simple gastric method, which measures bioaccessibility in the gastric compartment at low pHs of 1.5. Other methods that also apply a low gastric pH, and include intestinal conditions, produce lower bioaccessibility values. The lowest bioaccessibility values are observed for a gastrointestinal method which employs a high gastric pH of 4.0.     

Effects of gallotannin treatment on attachment, growth, and survival of Escherichia coli O157:H7 and Listeria monocytogenes on spinach and lettuce

Food-borne illness outbreaks are increasingly associated with fresh produce. Their high prevalence may reflect the lack of methods to effectively remove pathogenic bacteria from the surface of fruits and vegetables. This study evaluated the effect of antimicrobial gallotannins on attachment, growth, and survival of food-borne pathogens on green leafy vegetables. Spinach leaves and interior leaves of lettuce harboring high and low cell counts of background microbiota, respectively, were washed with tap water with and without added gallotannins. To account for the variability among organisms, green leafy vegetables were inoculated with strain cocktails of Escherichia coli O157:H7 and Listeria monocytogenes. Cell counts of L. monocytogenes were significantly reduced by the gallotannin treatment. Lower cell counts after storage for 8?days at 4?°C demonstrated antimicrobial effects of gallotannins retained on the surface of green leafy vegetables. Gallotannin treatments with 1?g/L did not inhibit E. coli O157:H7 but hindered their attachment to filter paper by up to 94?%. The addition of gallotannin-containing extracts from mango (Mangifera indica L.) kernels to the washing water did neither alter color nor texture of bagged fresh-cut products. In conclusion, gallotannin treatment significantly reduced surface contamination of green leafy vegetables with L. monocytogenes and reduced the attachment of cells of E. coli O157:H7.     

Dietary grape supplement ameliorates cerebral ischemia-induced neuronal death in gerbils

Oxidative damage has been implicated as one of the leading causes for neuronal cell death in a number of neurodegenerative diseases including stroke. Many vegetables and fruits are enriched in polyphenolic compounds known to exhibit antioxidant properties. This study is to investigate whether dietary supplement with grape powder (GP) may offer protection against neuronal damage due to global cerebral ischemia induced to Mongolian gerbils by occlusion of the common carotid arteries, a model known to cause delayed neuronal death (DND) in the hippocampal CA1 area. Gerbils were fed either a control diet (AIN76a) or a control diet supplemented with low (5.0 g/kg diet) or high (50 g/kg diet) levels of GP for two months. Four days after ischemia/reperfusion (I/R), the extent of DND, glial cell activation, nuclear DNA oxidation, and apoptotic terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) reaction in hippocampal CA1 region were assessed. Ischemia-induced extensive DND in the CA1 region was accompanied by oxidative and fragmented DNA damage and a marked increase in reactive astrocytes and microglial cells. Dietary GP supplementation significantly protected neurons against I/R-induced DND, DNA damage, and apoptosis as well as attenuated glial cell activation. These results demonstrate that due to the antioxidant properties of polyphenols in GP, nutritional diets supplemented with grape can protect the brain against ischemic damage. The neuroprotective effects of GP supplement may have wide implication in the future for prevention/protection against other neurodegenerative damage.     

The influence of potassium carbonate on surface area development and reactivity during gasification of activated carbon by carbon dioxide

In this study it is shown that the uncatalysed gasification of activated peat char can be described by a reaction temperature independent increase of the specific surface area with increasing burn-off and a constant reactivity per unit surface area up to 60% burn off. Unlike nickel catalysis, potassium catalysis causes an increased microporosity due to microchanneling. Above ca. 0.6 atoms per nm² the increase of the reactivity per unit surface area with increasing burn-off can be described by a first order dependency with respect to the number of potassium atoms per unit surface area. This can be explained by assuming potassium intercalate formation to be an essential step. The development of microporosity appears to be more pronounced at higher reactivities and, consequently, at higher effective catalyst loadings and higher reaction pressures.     

Stability and rheological behaviour of salad dressing obtained with whey and different combinations of stabilizers

In this work the stability and the rheological behaviour of salad dressing containing 'Minas Frescal' whey cheese was studied. The salad dressing was stabilised by xanthan gum (XG), propylene glycol alginate (PGA) and carboxymethylcellulose (CMC). All samples were stable for a period of 4 months. The rheological model of Ostwald-de-Waelle (Power-Law) was used in order to fit the data and to obtain the rheological parameters of flow behaviour index ( n ), consistency coefficient and apparent viscosity (η_ap). All formulations showed a pseudoplastic behaviour and the PGA contributed to increase the values of flow behaviour index. Consistency coefficient was similarly affected by XG and PGA fractions. Apparent viscosity was highly influenced by the hydrocolloid CMC, with higher values of apparent viscosity in the proportion of 0.25/0.25/0.5% (PGA/XG/CMC). Hydrocolloid association (ternary mixtures) was statistically significant, resulting in an increase of K and η_ap parameters. The results show that salad dressing with whey as aqueous phase and stabilised by a ternary combination of XG, PGA and CMC can be a technological alternative to the food industry.     

Evaluation of electrospray mass spectrometry as a technique for quantitative analysis of kinetically labile solution species

The extent that a kinetically labile equilibrium reaction was perturbed by passage through the electrospray ion source has been measured. The reaction studied was strontium ion chelation by EDTA (Sr(2+) + Y(4)(-) ? SrY(2)(-)) in 100% aqueous solutions. The forward reaction rate is very fast (10(9) M(-)(1) s(-)(1)) and the reverse rate is very slow (10(0) s(-)(1)) relative to the time scale of the ES process (～10(-2) s). The SrY(2-) detected with the mass spectrometer were expected to be representative of thermodynamic equilibrium within the droplets, but the position of the equilibrium shifted to the right relative to the solution equilibrium position. Given the current status of understanding of the ion generation process in the electrospray ion source, the degree that the [Sr(2+)] changed due to passage through this ion source was smaller than expected, which is fortuitous with respect to the quantitation of such species. The pH of each calibration set determined the fraction of strontium that was uncomplexed in solution. The equilibrium shift induced by passage through the ion source was constant for solutions at constant pH but differed for solutions at different pH. Decreasing the solution pH generated smaller equilibrium shifts as measured by the change in the [Sr(2+)]. In solutions with free Sr(2+) and excess EDTA at equilibrium, the free [Sr(2+)] decreased by ～100 and ～10% in solutions at pH 5.85 and 4.98, respectively. Quantitation of kinetically labile species in complex, multicomponent systems will be straightforward with ES-MS, provided all species involved in the equilibria can be identified and monitored.     

Effect of preparation method on the glycaemic index of novel potato clones

The purpose of this study was to investigate whether the effects of cooling and reheating on the glycaemic index (GI) of novel potato clones (selections) differed depending on selection and whether cooling altered starch absorption in vivo. We conducted 3 experiments using 4 novel potato clones in healthy subjects. Experiment 1: the GI of 4 selections each prepared in 3 ways (freshly boiled, cooled, or cooled and reheated) was measured in 2 groups of 10 subjects (each group tested 2 selections). Experiment 2 (n=10): two selections from Experiment 1 were re-tested one year later, by a different subject group. Experiment 3 (n=10): two selections from Experiment 1 were tested by subjects from Experiment 2 to assess the rate and extent of starch absorption using the second-meal effect and the breath hydrogen method, respectively. Experiment 1 demonstrated a selection×treatment interaction for GI (p=0.024); cooling reduced the GI of two selections by 40-50% (p<0.05) but reduced GI of the other 2 by only 8-10% (ns). Experiment 2 confirmed the selection×treatment interaction (p=0.018) seen in Experiment 1. Experiment 3: cooling reduced the GI by an average of 37% (p<0.05) but only increased starch malabsorption in vivo from 3% to 5% (p=0.021); there was no significant second-meal effect. It is concluded that the effect of cooling on the GI of potatoes may vary from 0-50% depending on selection. However, the mechanism for the effect is not clear: the 2% increase in starch malabsorption seen upon cooling potatoes was not nearly enough to account for the 37% reduction in GI.