The inhibition of intestinal glucose absorption by oat-derived avenanthramides.

Avenanthramides are phenolic compounds unique to oats and may contribute to health-promoting properties associated with oat consumption. This study used Xenopus laevis oocytes expressing the glucose transporters, glucose transporter 2 (GLUT2) or sodium-glucose transport protein 1 (SGLT1) and human Caco-2 cells models to investigate the effect of oat avenanthramides on human intestinal glucose transporters. The presence of avenanthramide reduced the glucose uptake in a dose-dependent manner in Caco-2 cells. Glucose uptake in oocytes expressing either GLUT2 or SGLT1 was nullified by oat avenanthramide. There was no significant difference between the inhibition potencies of avenanthramides C and B. Thus, our results suggest that avenanthramides may contribute to the antidiabetic properties of oats. PRACTICAL APPLICATIONS: The present research focus on the antidiabetic properties of avenanthramides, which are unique phenolic compounds found in oats. Inhibiting the activities of the glucose transport proteins expressed in the small intestine is a known strategy to improve the control of postprandial glucose level. We therefore examined the inhibitory effects of avenanthramides on two glucose transporters, glucose transporter 2 and sodium-glucose transport protein 1, predominantly found in the small intestine using the human small intestinal cell model Caco-2 cell line and by heterologously expressing these two transporters in the Xenopus laevis oocytes. Based on our results, we have confirmed for the first time that the glucose uptake is indeed inhibited by the presence of avenanthramides, suggesting the possibility of incorporating avenanthramides in foods to enhance postprandial glucose response, and ultimately improve the management of diabetes. Therefore, future research could consider utilizing this evidence in the development of diabetic-friendly functional foods or nutraceuticals containing avenanthramides.

Avenanthramide supplementation reduces eccentric exercise-induced inflammation in young men and women.

BACKGROUND: Avenanthramides (AVA) are a group of di-phenolic acids found only in oats and have shown antioxidant and anti-inflammatory effects in vitro and in vivo. Eccentric muscle contraction is intimately involved in rigorous exercise that activates systemic and local inflammatory responses. The objective of the study is to evaluate whether chronic AVA supplementation could attenuate peripheral inflammatory and immunological markers in human subjects in response to an acute bout of downhill running (DR). METHODS: Eleven male and thirteen female subjects voluntarily participated in this double-blinded, randomized controlled study and were randomly divided into AVA-supplemented (AVA) or control (C) groups. All subjects conducted a DR protocol at - 10% grade with an intensity equivalent to 75% of their maximal heart rate. Blood samples were collected at rest and various time points (0-72 h) after DR (PRE). After an 8-week washout period, participants received two cookies daily containing either 206 mg/kg (AVA) or 0 mg/kg (C) AVA for 8 weeks. Following the oat supplementation regimen, the DR and blood sampling protocols were repeated (POST). Plasma inflammatory and immunological markers were measured using Multiplex immunoassay and muscle soreness was evaluated with pain rating scale. RESULTS: DR increased plasma creatine kinase (CK) activity (P < 0.01) during PRE, but the response was reduced at 24 and 48 h during POST vs. PRE regardless of AVA status (P < 0.05). Neutrophil respiratory burst (NRB) levels were elevated at 4 and 24 h (P < 0.05) during PRE but were significantly decreased at 0-48 h during POST vs. PRE (P < 0.05 or 0.01). Granulocyte-colony stimulating factor (G-CSF), the neutrophil stimulating cytokine, was also increased in response to DR but showed lower levels in AVA compared to C during POST vs. PRE (P < 0.05). Plasma interleukin-6 (IL-6) content showed an increase at 0 and 4 h during PRE and 0 h during POST (P < 0.01), whereas during POST there was a trend toward a lower IL-6 level in AVA vs. C (P = 0.082). Plasma levels of anti-inflammatory agent interleukin-1 receptor antagonist (IL-1Ra) showed an increase at 4 h during PRE, and was significantly elevated in AVA vs. C during POST. Both soluble vascular cell adhesion molecule-1 (sVCAM-1) and monocyte chemoattractant protein-1 (MCP-1) contents increased at 0 and 24 h post DR during PRE as well as POST sessions, however, sVCAM-1 content was lower in AVA vs. C during POST (P < 0.05) and MCP-1 levels were below resting level at 24, 48 and 72 h during POST (P < 0.05). DR increased muscle pain at all post-DR time points (P < 0.01), but the pain level was alleviated by oat supplementation at 48 and 72 h during POST regardless of AVA treatment (P < 0.05). CONCLUSIONS: Oat AVA supplementation reduced circulatory inflammatory cytokines and inhibited expression of chemokines and cell adhesion molecules induced by DR. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02584946 . Registered 23 October 2015.

Enhancement of γ-aminobutyric acid, avenanthramides, and other health-promoting metabolites in germinating oats (Avena sativa L.) treated with and without power ultrasound.

Power ultrasound as an emerging processing technology has been investigated for stimulating seeds to enhance germination and accumulation of health-promoting metabolites, such as γ-aminobutyric acid (GABA) and phenolic compounds. This work was undertaken to evaluate the effects of power ultrasound (25 kHz) on the nutritional properties of germinated oats, and the microstructure of oat groats after treatment. The changes in the external and internal microstructures of the ultrasound-treated oats kernel were investigated using Environmental Scanning Electron Microscopy (ESEM) and 3D X-ray Micro Computed Tomography (Micro-CT). Physicochemical properties of oats including GABA, free sugars, avenanthramides, total phenolic content, and antioxidant capacities were enhanced after germination. Furthermore, the power ultrasound treatment for 5 min after soaking significantly enhanced the GABA (48-96 h), alanine (24-96 h), succinic acid (48-72 h), total phenolic content (24 h), and total avenanthramides (24 h) in the germinated oats.

Absorption and Elimination of Oat Avenanthramides in Humans after Acute Consumption of Oat Cookies.

BACKGROUND: Avenanthramides (AVA) are a group of diphenolic acids found only in oats that have anti-inflammatory and antioxidant effects. Absorption of AVAs in humans after oral consumption of natural oat flour is unknown. OBJECTIVE: To examine the appearance of AVAs in plasma after oral ingestion of oat cookies and estimate key pharmacokinetic parameters. METHODS: Male and female nonobese participants (n = 16) consumed three cookies made with oat flour containing high (229.6 mg/kg, H-AVA) or low (32.7 mg/kg, L-AVA) amounts of AVAs, including AVA-A, AVA-B, and AVA-C. Blood samples were collected at 0, 0.5, 1, 2, 3, 5, and 10 h after ingestion. Plasma total (conjugated and free) AVA concentrations were quantified using UPLC-MS, and pharmacokinetic parameters for each AVA were estimated. RESULTS: AVAs reached peak concentrations in plasma between 2 and 3 h for the H-AVA group and between 1 and 2 h for the L-AVA group. Maximal plasma concentrations for AVAs were higher in the H-AVA than in the L-AVA group. AVA-B demonstrated a longer half-life and slower elimination rate than AVA-A and AVA-C. CONCLUSIONS: AVAs found naturally in oats are absorbed in the plasma after oral administration in humans. AVA-B has the slowest elimination rate and the longest half-life compared to AVA-A and AVA-C, while AVA-C demonstrated the lowest plasma concentrations. This study is registered with ClinicalTrials.gov identifier NCT02415374.

Instant Oatmeal Increases Satiety and Reduces Energy Intake Compared to a Ready-to-Eat Oat-Based Breakfast Cereal: A Randomized Crossover Trial.

BACKGROUND: Foods that enhance satiety can help consumers to resist environmental cues to eat and help adherence to calorie restriction. The objective of this study was to compare the effect of 2 oat-based breakfast cereals on appetite, satiety, and food intake. METHODS: Forty-eight healthy individuals, 18 years of age or older, were enrolled in a randomized, crossover trial. Subjects consumed isocaloric servings of either oatmeal or an oat-based ready-to-eat breakfast cereal (RTEC) in random order at least a week apart. Visual analogue scales measuring appetite and satiety were completed before breakfast and throughout the morning. Lunch was served 4 hours after breakfast. The physicochemical properties of oat soluble fiber (ß-glucan) were determined. Appetite and satiety responses were analyzed by area under the curve. Food intake and ß-glucan properties were analyzed using t tests. RESULTS: Oatmeal increased fullness (p = 0.001) and reduced hunger (p = 0.005), desire to eat (p = 0.001), and prospective intake (p = 0.006) more than the RTEC. Energy intake at lunch was lower after eating oatmeal compared to the RTEC (p = 0.012). Oatmeal had higher viscosity (p = 0.03), ß-glucan content, molecular weight (p < 0.001), and radius of gyration (p < 0.001) than the RTEC. CONCLUSIONS: Oatmeal suppresses appetite, increases satiety, and reduces energy intake compared to the RTEC. The physicochemical properties of ß-glucan and sufficient hydration of oats are important factors affecting satiety and subsequent energy intake.

Avenanthramide supplementation attenuates eccentric exercise-inflicted blood inflammatory markers in women.

PURPOSE: Rigorous exercise is known to generate reactive oxygen species (ROS) and inflict inflammatory response. The present study investigated whether dietary supplementation of avenanthramides (AVA) in oats would increase antioxidant protection and reduce inflammation in humans after an acute bout of eccentric exercise. METHODS: Young women (age 18-30 years, N = 16) were randomly divided into two groups in a double-blinded fashion, receiving two cookies made of oat flour providing 9.2 mg AVA (AVA) or 0.4 mg AVA (Control, C) each day for 8 weeks. Before and after the dietary regimen each group of subjects ran downhill (DR) on a treadmill at -9% grade for 1 h at a speed to elicit 75% of maximal heart rate. Blood samples were collected at rest, immediately and 24 h post-DR. RESULTS: Before dietary supplementation plasma creatine kinase activity and tumor necrosis factor (TNF)-α concentration were increased immediately after DR (P < 0.05), whereas neutrophil respiratory burst (NRB) was elevated 24 h post-DR (P < 0.05). CK and TNF-α response to DR was abolished during post-supplementation tests in both AVA and C groups, whereas NRB was blunted only in AVA but not in C. Plasma interleukin-6 level and mononuclear cell nuclear factor (NF) κB activity were not affected by DR either before or after dietary supplementation, but were lowered 24 h post-DR in AVA versus C (P < 0.05). Both groups increased plasma total antioxidant activity following 8-week dietary regimen (P < 0.05), whereas only AVA group increased resting plasma glutathione (GSH) concentration (P < 0.05), decreased glutathione disulfide response to DR, and lowered erythrocyte GSH peroxidase activity (P < 0.05). CONCLUSIONS: Our data of pre- and post-supplementation difference reflect an interaction between repeated measure effect of eccentric exercise and AVA in diet. Long-term AVA supplementation can attenuate blood inflammation markers, decrease ROS generation and NFkB activation, and increased antioxidant capacity during an eccentric exercise bout.

The role of meal viscosity and oat ß-glucan characteristics in human appetite control: a randomized crossover trial.

BACKGROUND: Foods that enhance satiety can help consumers to resist environmental cues to eat, and improve the nutritional quality of their diets. Viscosity generated by oat ß-glucan, influences gastrointestinal mechanisms that mediate satiety. Differences in the source, processing treatments, and interactions with other constituents in the food matrix affect the amount, solubility, molecular weight, and structure of the ß-glucan in products, which in turn influences the viscosity. This study examined the effect of two types of oatmeal and an oat-based ready-to-eat breakfast cereal (RTEC) on appetite, and assessed differences in meal viscosity and ß-glucan characteristics among the cereals. METHODS: Forty-eight individuals were enrolled in a randomized crossover trial. Subjects consumed isocaloric breakfast meals containing instant oatmeal (IO), old-fashioned oatmeal (SO) or RTEC in random order at least a week apart. Each breakfast meal contained 218 kcal (150 kcal cereal, and 68 kcal milk) Visual analogue scales measuring appetite were completed before breakfast, and over four hours, following the meal. Starch digestion kinetics, meal viscosities, and ß-glucan characteristics for each meal were determined. Appetite responses were analyzed by area under the curve. Mixed models were used to analyze response changes over time. RESULTS: IO increased fullness (p = 0.04), suppressed desire to eat (p = 0.01) and reduced prospective intake (p < 0.01) more than the RTEC over four hours, and consistently at the 60 minute time-point. SO reduced prospective intake (p = 0.04) more than the RTEC. Hunger scores were not significantly different except that IO reduced hunger more than the RTEC at the 60 minute time-point. IO and SO had higher ß-glucan content, molecular weight, gastric viscosity, and larger hydration spheres than the RTEC, and IO had greater viscosity after oral and initial gastric digestion (initial viscosity) than the RTEC. CONCLUSION: IO and SO improved appetite control over four hours compared to RTEC. Initial viscosity of oatmeal may be especially important for reducing appetite.

Effects of three intense sweeteners on fat storage in the C. elegans model.

Beverages sweetened with caloric sweeteners (CS), glucose, sucrose or high-fructose corn syrup, are associated with weight gain. Beverages sweetened with intense sweeteners (IS) are marketed as low-calorie substitutes to prevent beverages-associated weight gain. Using Caenorhabditis elegans, the effects on intestinal fat deposition (IFD) and pharyngeal pumping rate (PPR) of cola beverages sweetened with glucose, aspartame, or aspartame plus acesulfame-potassium (AceK) were compared. Control groups received Escherichia coli (OP50) only. Study I: the nematodes received additional glucose- or IS-sweetened beverages. Study II: the nematodes received additional glucose, aspartame, or aspartame plus AceK (AAK). Beverages containing CS or IS (aspartame or AAK) did not alter IFD in wild type (N2) or in daf-16 deficiency. The CS cola increased IFD in sir-2.1 deficiency (P<0.05). The AAK-cola increased IFD in daf-16/daf-2 deficiency and sir-2.1 deficiency (P<0.05). Glucose increased IFD in N2 and daf-16 deficiency (P<0.05). Aspartame showed a tendency towards reduced IFD in N2 and decreased IFD in daf-16/daf-2 deficiency (P<0.05). AAK increased IFD in daf-16 deficiency and sir-2.1 deficiency (P<0.05), and reversed the aspartame-induced reduction in IFD. The aspartame-sweetened cola increased the PPR in daf-16/daf-2 deficiency and daf-16 deficiency (P<0.05); similar results were obtained in N2 with both IS (P<0.05). AAK increased the PPR in daf-16/daf-2, daf-16, and sir-2.1 deficiencies (P<0.05). Thus, IS increased the PPR, a surrogate marker of lifespan. Aspartame may have an independent effect in reducing IFD to assist humans desiring weight loss. AceK may increase IFD in presence of insulin resistance.

Avenanthramide supplementation attenuates exercise-induced inflammation in postmenopausal women.

During aging, chronic systemic inflammation increases in prevalence and antioxidant balance shifts in favor of oxidant generation. Avenanthramide (AVA) is a group of oat phenolics that have shown anti-inflammatory and antioxidant capability. The present study investigated whether dietary supplementation of avenanthramides (AVA) in oats would increase antioxidant protection and reduce inflammation after a bout of downhill walking (DW) in postmenopausal women. Women at age of 50-80 years (N = 16) were randomly divided into two groups in a double-blinded fashion, receiving two cookies made of oat flour providing 9.2 mg AVA or 0.4 mg AVA (control, C) each day for 8 weeks. Before and after the dietary regimen, each group of subjects walked downhill on a treadmill (-9% grade) for 4 bouts of 15 minutes at a speed of 4.0 km/h with 5 minutes rest between sessions. Blood samples were collected at rest, 24 h post-DW, and 48 h post-DW pre- and post-supplementation. Both DW sessions increased plasma creatine kinase activity (P < 0.05). Before supplementation, in vitro neutrophil respiratory burst (NRB) activity was increased at 24 h post-DW (P < 0.05) and C-reactive protein (CRP) was increased 48 h post-DW (P < 0.05). AVA supplementation decreased DW-induced NRB at 24 h (P < 0.05) and CRP level 48 h (P < 0.05). Plasma interleukin (IL)-1ß concentration and mononuclear cell nuclear factor (NF) κB binding were suppressed at rest and during post-DW period in AVA but not C group (P < 0.05). Plasma total antioxidant capacity (P < 0.05) and erythrocyte superoxide dismutase activity were increased in AVA vs. C (P < 0.05), whereas glutathione redox status was elevated 48 h post-DW but not affected by AVA. Thus, chronic AVA supplementation decreased systemic and DW-induced inflammation and increased blood-borne antioxidant defense in postmenopausal women.

Acute effect of oatmeal on subjective measures of appetite and satiety compared to a ready-to-eat breakfast cereal: a randomized crossover trial.

OBJECTIVE: The physicochemical properties of soluble oat fiber (ß-glucan) affect viscosity-dependent mechanisms that influence satiety. The objective of this study was to compare the satiety impact of oatmeal with the most widely sold ready-to-eat breakfast cereal (RTEC) when either was consumed as a breakfast meal. METHODS: Forty-eight healthy individuals ≥18 years of age were enrolled in a randomized crossover trial. Following an overnight fast, subjects consumed either oatmeal or RTEC in random order at least a week apart. The breakfasts were isocaloric and contained 363 kcal (250 kcal cereal, 113 kcal milk). Visual analogue scales measuring appetite and satiety were completed before breakfast and throughout the morning. The content and physicochemical properties of oat ß-glucan were determined. Appetite and satiety responses were analyzed by area under the curve (AUC). Physicochemical properties were analyzed using t tests. RESULTS: Oatmeal, higher in fiber and protein but lower in sugar than the RTEC, resulted in greater increase in fullness (AUC: p = 0.005 [120 minute: p = 0.0408, 180 minute: p = 0.0061, 240 minute: p = 0.0102]) and greater reduction in hunger (AUC: p = 0.0009 [120 minute: p = 0.0197, 180 minute: p = 0.0003, 240 minute: p = 0.0036]), desire to eat (AUC: p = 0.0002 [120 minute: p = 0.0168, 180 minute: p < 0.0001, 240 minute: p = 0.0022]), and prospective intake (AUC: p = 0.0012 [120 minute: p = 0.0058, 180 minute: p = 0.006, 240 minute: p = 0.0047]) compared to the RTEC. Oatmeal had higher ß-glucan content, higher molecular weight (p < 0.0001), higher viscosity (p = 0.025), and larger hydration spheres (p = 0.0012) than the RTEC. CONCLUSION: Oatmeal improves appetite control and increases satiety. The effects may be attributed to the viscosity and hydration properties of its ß-glucan content.

In vitro antioxidant capacity and anti-inflammatory activity of seven common oats.

Oats are gaining increasing scientific and public interest for their purported antioxidant-associated health benefits. Most reported studies focused on specific oat extracts or particular oat components, such as ß-glucans, tocols (vitamin E), or avenanthramides. Studies on whole oats with respect to antioxidant and anti-inflammatory activities are still lacking. Here the antioxidant and anti-inflammatory activities from whole oat groats of seven common varieties were evaluated. All oat varieties had very similar oxygen radical absorption capacity compared with other whole grains. In an anti-inflammatory assay, oat variety CDC Dancer inhibited tumor necrosis factor-α induced nuclear factor-kappa B activation by 27.5% at 2 mg/ml, whereas variety Deiter showed 13.7% inhibition at a comparable dose. Avenanthramide levels did not correlate with the observed antioxidant and anti-inflammatory activities. Further investigations are needed to pinpoint the specific antioxidant and anti-inflammatory compounds, and potential synergistic and/or matrix effects that may help explain the mechanisms of oat's anti-inflammatory actions.

Coffee, but not caffeine, has positive effects on cognition and psychomotor behavior in aging.

The complex mixture of phytochemicals in fruits and vegetables provides protective health benefits, mainly through additive and/or synergistic effects. The presence of several bioactive compounds, such as polyphenols and caffeine, implicates coffee as a potential nutritional therapeutic in aging. Moderate (three to five cups a day) coffee consumption in humans is associated with a significant decrease in the risk of developing certain chronic diseases. However, the ability of coffee supplementation to improve cognitive function in aged individuals and the effect of the individual components in coffee, such as caffeine, have not been fully evaluated. We fed aged rats (19 months) one of five coffee-supplemented diets (0, 0.165, 0.275, 0.55, and 0.825% of the diet) for 8 weeks prior to motor and cognitive behavior assessment. Aged rats supplemented with a 0.55% coffee diet, equivalent to ten cups of coffee, performed better in psychomotor testing (rotarod) and in a working memory task (Morris water maze) compared to aged rats fed a control diet. A diet with 0.55% coffee appeared to be optimal. The 0.165% coffee-supplemented group (three cups) showed some improvement in reference memory performance in the Morris water maze. In a subsequent study, the effects of caffeine alone did not account for the performance improvements, showing that the neuroprotective benefits of coffee are not due to caffeine alone, but rather to other bioactive compounds in coffee. Therefore, coffee, in achievable amounts, may reduce both motor and cognitive deficits in aging.

Flaking process increases the NF-κB inhibition activity and melanoidin extractability of coffee.

Research on the health impacts of coffee has escalated. However, few studies were devoted to understanding the potential impact of mechanical processing on coffee's chemistry and subsequent health implications. Coffee flaking is a commonly used process to improve extractability and aroma characteristics. In this study, we studied the biochemical activity, chemical composition, and microstructure of coffee before and after flaking. We found that flaked coffee extract had 3.3-fold higher activity in inhibiting nuclear factor-kappa B (NF-κB) activation than regular coffee extract. Interestingly, flaking did not significantly alter the amount of coffee phenolics. It increased coffee melanoidin, by 2.1-fold, which likely contributed to the observed higher activity in inhibiting NF-κB activation. Flaking crushed cell walls revealed by microscopy might possibly result in disruption of polysaccharide entanglement and release of high-molecular-weight compounds, such as melanoidins. Consequently, the increased melanoidin content in the brew resulted in the increased inhibition of NF-κB activation. Small molecules, like coffee phenolics, are readily soluble in water during coffee brewing even without flaking, suggesting that flaking has no effect on its extractability. In summary, our investigation revealed that flaking enhanced NF-κB inhibition activity, possibly through the release of melanoidins from crushed cell microstructures.

Crude caffeine reduces memory impairment and amyloid ß(1-42) levels in an Alzheimer's mouse model.

Alzheimer's disease (AD), a chronic neurodegenerative disorder associated with the abnormal accumulations of amyloid ß (Aß) peptide and oxidative stress in the brain, is the most common form of dementia among the elderly. Crude caffeine (CC), a major by-product of the decaffeination of coffee, has potent hydrophilic antioxidant activity and may reduce inflammatory processes. Here, we showed that CC and pure caffeine intake had beneficial effects in a mouse model of AD. Administration of CC or pure caffeine for 2months partially prevented memory impairment in AD mice, with CC having greater effects than pure caffeine. Furthermore, consumption of CC, but not pure caffeine, reduced the Aß(1-42) levels and the number of amyloid plaques in the hippocampus. Moreover, CC and caffeine protected primary neurons from Aß-induced cell death and suppressed Aß-induced caspase-3 activity. Our data indicate that CC may contain prophylactic agents against the cell death and the memory impairment in AD.

Supercritical CO2 decaffeination of unroasted coffee beans produces melanoidins with distinct NF-κB inhibitory activity.

UNLABELLED: The supercritical CO(2)-decaffeination process causes unroasted coffee beans to turn brown. Therefore, we suspected that the decaffeinated beans contained melanoidins. Decaffeinated unroasted coffee extract absorbed light at 405 nm with a specific extinction coefficient, K(mix 405 nm), of 0.02. Membrane dialysis (molecular weight cut-off, 12 to 14 kDa) increased the K(mix 405 nm) value 15 fold. Gel filtration chromatography showed that the high-MW fraction (MW > 12 kDa) had an elution profile closer to that of melanoidins of medium-roast coffee than to the corresponding fraction of unroasted coffee, indicating the presence of melanoidins in decaffeinated unroasted beans. Using murine myoblast C2C12 cells with a stably transfected nuclear factor-κB (NF-κB) luciferase reporter gene, we found that the high-MW fraction of decaffeinated unroasted beans had an NF-κB inhibitory activity of IC(50) = 499 µg/mL, more potent than that of regular-roast coffee (IC(50) = 766 µg/mL). Our results indicate that melanoidins form during the supercritical CO(2)-decaffeination process and possess biological properties distinct from those formed during the regular roasting process. PRACTICAL APPLICATION: We discovered the roasting effect of decaffeination process, reporting the discovery of melanoidins in green (unroasted) decaf coffee beans. Our results indicated that melanoidins form during the supercritical CO2-decaffeination process and possess biological properties distinct from those formed during the regular roasting process. Our results offer new insights into the formation of bioactive coffee components during coffee decaffeination process.

Roasted coffees high in lipophilic antioxidants and chlorogenic acid lactones are more neuroprotective than green coffees.

Oxidative stress is involved in many neurodegenerative processes leading to age-related cognitive decline. Coffee, a widely consumed beverage, is rich in many bioactive components, including polyphenols with antioxidant potential. In this study, regular and decaffeinated samples of both roasted and green coffee all showed high hydrophilic antioxidant activity in vitro, whereas lipophilic antioxidant activities were on average 30-fold higher in roasted than in green coffee samples. In primary neuronal cell culture, pretreatment with green and roasted coffees (regular and decaffeinated) protected against subsequent H(2)O(2)-induced oxidative stress and improved neuronal cell survival (green coffees increased neuron survival by 78%, compared to 203% by roasted coffees). All coffee extracts inhibited ERK1/2 activation, indicating a potential attenuating effect in stress-induced neuronal cell death. Interestingly, only roasted coffee extracts inhibited JNK activation, evidencing a distinctive neuroprotective benefit. Analysis of coffee phenolic compounds revealed that roasted coffees contained high levels of chlorogenic acid lactones (CGLs); a significant correlation between CGLs and neuroprotective efficacy was observed (R(2) = 0.98). In conclusion, this study showed that roasted coffees are high in lipophilic antioxidants and CGLs, can protect neuronal cells against oxidative stress, and may do so by modulation of the ERK1/2 and JNK signaling pathways.

Immobilization of bioluminescent Escherichia coli cells using natural and artificial fibers treated with polyethyleneimine.

Biosensors based on whole-cell bioluminescence have the potential to become a cost-effective alternative to conventional detection methods upon validation of target selectivity and sensitivity. However, quantitative analysis of bioluminescence is greatly hindered due to lack of control over the total number of cells in a suspending culture. In this study, the effect of surface properties of genetically engineered luminous E. coli cells and fibrous matrices on the immobilization capacity and effectiveness under various environmental conditions were characterized. Four different fibers, including cotton, polyester, viscose rayon, and silk, were investigated. Although cell adhesion was observed on untreated viscose and cotton fibers, viscose fiber pretreated with 0.667% polyethyleneimine (PEI) was found capable of immobilizing the most viable E. coli DPD2234 cells, followed by viscose treated with 0.33% and 1% PEI. The cells immobilized on PEI-treated viscose remained viable and yielded 20% or more bioluminescence signals immediately upon contact with the inducer up to 72 h without feeding nutrients to the cells, suggesting that viscose treated with 0.667% PEI could provide a stable immobilization mechanism for bioluminescent E. coli cells with long sensing period, quick response time, and good signal reproducibility.

Cranberries inhibit LDL oxidation and induce LDL receptor expression in hepatocytes.

Cardiovascular disease (CVD) is the leading cause of death in most industrialized countries. Cranberries were evaluated for their potential roles in dietary prevention of CVD. Cranberry extracts were found to have potent antioxidant capacity preventing in vitro LDL oxidation with increasing delay and suppression of LDL oxidation in a dose-dependent manner. The antioxidant activity of 100 g cranberries against LDL oxidation was equivalent to 1000 mg vitamin C or 3700 mg vitamin E. Cranberry extracts also significantly induced expression of hepatic LDL receptors and increased intracellular uptake of cholesterol in HepG2 cells in vitro in a dose-dependent manner. This suggests that cranberries could enhance clearance of excessive plasma cholesterol in circulation. We propose that additive or synergistic effects of phytochemicals in cranberries are responsible for the inhibition of LDL oxidation, the induced expression of LDL receptors, and the increased uptake of cholesterol in hepatocytes.

Novel low-density lipoprotein (LDL) oxidation model: antioxidant capacity for the inhibition of LDL oxidation.

A novel model of peroxyl radical initiated low-density lipoprotein (LDL) oxidation (LDL oxidation model for antioxidant capacity, or LOMAC) was developed to assess the free radical scavenging capacity of antioxidants and the extracts of natural products. A water-soluble free radical initiator, 2,2'-azobis(amidinopropane) dihydrochloride, was used at physiological temperature (37 degrees C) to generate peroxyl radicals to catalyze lipid oxidation of LDL isolated from human plasma samples. Headspace hexanal, a major decomposition product of LDL oxidation, was measured by a headspace gas chromatograph as an indicator of antioxidant capacity of different concentrations of pure antioxidants (vitamins C and E) and the extracts of natural products (fresh apple phytochemical extracts). All vitamin C and E and apple extract concentrations tested resulted in increasing partial suppression and delay of LDL oxidation. On the basis of the median effective dose (EC(50)) calculated for each compound or extract tested, the LOMAC value of 100 g of apple against LDL oxidation was equivalent to 1470 mg of vitamin E or to 402 mg of vitamin C. This study shows that the LOMAC assay can be routinely used to analyze or screen antioxidants or phytochemical extracts against LDL oxidation to prevent cardiovascular disease. The food-specific LOMAC values will be very useful as a new alternative biomarker for future epidemiological studies of cardiovascular disease.

Antioxidant and antiproliferative activities of common fruits.

Consumption of fruits and vegetables has been associated with reduced risk of chronic diseases such as cardiovascular disease and cancer. Phytochemicals, especially phenolics, in fruits and vegetables are suggested to be the major bioactive compounds for the health benefits. However, the phenolic contents and their antioxidant activities in fruits and vegetables were underestimated in the literature, because bound phenolics were not included. This study was designed to investigate the profiles of total phenolics, including both soluble free and bound forms in common fruits, by applying solvent extraction, base digestion, and solid-phase extraction methods. Cranberry had the highest total phenolic content, followed by apple, red grape, strawberry, pineapple, banana, peach, lemon, orange, pear, and grapefruit. Total antioxidant activity was measured using the TOSC assay. Cranberry had the highest total antioxidant activity (177.0 +/- 4.3 micromol of vitamin C equiv/g of fruit), followed by apple, red grape, strawberry, peach, lemon, pear, banana, orange, grapefruit, and pineapple. Antiproliferation activities were also studied in vitro using HepG(2) human liver-cancer cells, and cranberry showed the highest inhibitory effect with an EC(50) of 14.5 +/- 0.5 mg/mL, followed by lemon, apple, strawberry, red grape, banana, grapefruit, and peach. A bioactivity index (BI) for dietary cancer prevention is proposed to provide a new alternative biomarker for future epidemiological studies in dietary cancer prevention and health promotion.