Search

The perception of odor mixtures plays an important role in human food intake, behavior, and emotions. Decline of smell acuity with normal aging could impact food perception and preferences at various ages. However, since the landmark Smell Survey by National Geographic, little has been elucidated on differences in the onset and extent of loss in olfactory sensitivity toward single odorants. Here, using the Specific Sensitivity test, we show the onset and extent of loss in both identification and detection thresholds of odorants with age are odorant-specific. Subjects of Chinese descent in Singapore (186 women, 95 men), aged 21-80 years, were assessed for olfactory sensitivity of 10 odorants from various odor groups. Notably, subjects in their 70s required 179 times concentration of rose-like odorant (2-phenylethanol) than subjects in the 20s, while thresholds for onion-like 2-methyloxolane-3-thiol only differed by 3 times between the age groups. In addition, identification rate for 2-phenylethanol was negatively correlated with age throughout adult life whereas mushroom-like oct-1-en-3-ol was equally identified by subjects across all ages. Our results demonstrated the girth of differentiated olfactory loss due to normal ageing, which potentially affect overall perception and preferences of odor mixtures with age. [ABSTRACT FROM AUTHOR]

Glyceollin I, an induced phytoalexin isolated from soybean, has been reported to have various bioactivities, including anti-bacterial, anti-nematode, anti-fungal, antiestrogenic and anti-cancer, anti-oxidant, anti-inflammatory, insulin sensitivity enhancing, and attenuation of vascular contractions. Here we show that glyceollin I has hormesis and extends yeast life span at low (nM) doses in a calorie restriction (CR)-dependent manner, while it reduces life span and inhibits yeast cell proliferation at higher (μM) doses. In contrast, the other two isomers (glyceollin II and III) cannot extend yeast life span and only show life span reduction and antiproliferation at higher doses. Our results in anti-aging activity indicate that glyceollin I might be a promising calorie restriction mimetic candidate, and the high content of glyceollins could improve the bioactivity of soybean as functional food ingredients. [ABSTRACT FROM AUTHOR]

Ethanolic extract of durian seeds was fractionated by reverse phase flash column chromatography and the fractions characterized by electrospray ionization mass spectroscopy. Among a few unknown compounds collected, oligomeric proanthocyanidins (OPCs) were found to be one of the main compounds. Based on this result, the OPCs were purified the first time from the durian seeds using standard procedures and gave a yield of 1.8 mg/g dry matter after fractionation by Sephadex LH-20 column. Structural analysis by 13C{1H} NMR and ESI-MS spectra showed the presence of primarily B-type procyanidins with mainly epicatechin as the extension units, which was further verified by matrix assisted laser desorption/ionization-time of flight mass spectra (MALDI-TOF MS), which shows a distribution of dimers to decamers. In addition, hydroxylated peaks with molecular weight 16 units more than the poly-epicatechins represented significant peaks. We suggest this might be due to hydroxylation occurring under the MALDI-TOF MS conditions. Consistently, depolymerization with α-toluenethiol resulted in epicatechin thioether as the major product, but undetectable amount of gallocatechin or its α-toluenethiol derivatives. The oligomershave a mean degree of polymerization of 7.30. [ABSTRACT FROM AUTHOR]

The α-amylase and α-glucosidase inhibition activity of 92 Traditional Chinese Medicinal (TCM) herbs, which are permitted to be used as food ingredients, were evaluated using the high throughput assay developed in our laboratory. Among these herbs, twenty-seven of them possessed significant α-amylase inhibition activities ranging from 2.4 to 349.2/µmol AE/g (AE = acarbose equivalent) with inhibition concentrations at 50% inhibition (IC50) from 16.0 to 2342.2/µg/mL, respectively. In addition, they showed α-glucosidase inhibition activities ranging from 0.5 to 31.6 µmolAE/g (IC50 from 49.0 to 3385.5/µg/mL). The extracts of Rhizoma fagopyri dibotryis (Jĩnqiáomài), Rosa rugosa (Méiguīuā), Caulis polygoni multiflori (Shŏuwūténg), Fructus amomi (Shārén), Rhizoma alpiniae officinarum (Gāoliáingjiāng), Folium ginkgo (Yínxìngyè) and Cortex cinnamomi (Ròuguì) showed the better inhibitory activities against both α-amylase and α-glucosidase. Our results illustrated that these food grade herbs are potent natural hypoglycemic agents and can be used as active ingredients for low glycemic index food production or TCM herbal formulations for controlling hyperglycemia. [ABSTRACT FROM AUTHOR]

Proanthocyanidins from the rhizomes of Selliguea feei (PSFs) were solvent-extracted and fractionated by Sephadex LH-20 column chromatography to give a 2.42% isolated yield (dry matter basis). 1H-NMR spectroscopy revealed the mean degree of polymerization (mDP) to be 2.6. 13C-NMR analysis showed typical signals for afzelechin/epiafzelechin units. Clear peaks at 76 ppm and 84 ppm indicated that both stereoisomers (afzelechin/epiafzelechin) are present. In agreement with the NMR spectra, the ESI-MS spectrum indicated that PSFs are mainly monomers to trimers consisting of afzelechin/epiafzelechin units with A-type and B-type interflavanyl linkages. A trimer was purified and identified as demethylated selligueain B. Thiolysis confirmed the structure and the thiolytic products, methyl 2-[(2R, 3R, 4S)-3,5,7-trihydroxy-2-(4-hydroxyphenyl)chroman-4-yl]acetate (1) and 4β-(carboxymethyl)sulphanylepiafzelechin-(2β→O→7,4β→8)-epiafzelechin methyl ester (2), were purified and characterized. Selligueain A, demethylated selligueain B, compounds 1 and 2 possess high antioxidant capacity at 1.18 × 104, 1.16 × 104, 0.95 × 104 and 1.29 × 104 μmol TE/g, respectively. [ABSTRACT FROM AUTHOR]

A fluorescent assay for simultaneous screening of myeloperoxidase (MPO) inhibitors and hypochlorous acid (HOCl) scavengers was developed using quantum dots (QDs) as a selective HOCl probe. HL60 cells were differentiated into neutrophil phenotype and used for HOCl generation in this assay. The fluorescence of QDs was specifically quenched by HOCl generated from the neutrophil-like cells induced with phorbol 12-myristate 13-acetate (PMA) or hydrogen peroxide (H2O2 ). Both MPO inhibitors (e.g. resveratrol) and HOCl scavengers (methionine and vitamin C) tested in this assay could inhibit the QDs fluorescence quenching but MPO inhibitors showed a more obvious dose response relationship than HOCl scavengers. A microplate assay under the same conditions using 2,7-dichlorofluorescin diacetate (DCFH-DA), a commonly used reactive oxidative species (ROS) probe, was also performed to make a comparison with QDs based assay. The results indicated superior HOCl specificity of QDs over DCFH-DA and necessity of using ROS probes with different selectivity for a comprehensive evaluation of antioxidant efficiency in cellular systems. This QDs based microplate assay has a potential to be used in cell line-based high throughput screening for HOCl scavengers or MPO inhibitors with therapeutic importance in controlling inflammation. [ABSTRACT FROM AUTHOR]

Characterzation of polyphenolic compounds in the stems of P. multiflorum was conducted using HPLC, high resolution LC-MS and LC-MSn. Proanthocyanidins in particular were isolated in 4.8% yield using solvent extraction followed by Sephadex LH-20 fractionation. HPLC analysis using a diol column revealed oligomers (from dimer to nonamer) as minor components, with (epi)catechin monomeric units predominating, and oligomers with higher degree of polymerization being dominant. Thiolysis treatment of the proanthocyanidins using mercaptoacetic acid produced thioether derivatives of (epi)catechin as the major product and a mean value of the degree of polymerization of 32.6 was estimated from the ratio of terminal and extension units of the (epi)catechin. The isolated proanthocyanidins were shown to strongly inhibit α-amylase with an acarbose equivalence (AE) value of 1,954.7 μmol AE/g and inhibit α-glucosidase with an AE value of 211.1 μmol AE/g. [ABSTRACT FROM AUTHOR]

Aims The present study aims to investigate the interaction between nitric oxide (NO) and hydrogen sulfide (H2S), the two important gaseous mediators in rat hearts. Methods and results Intracellular calcium in isolated cardiomyocytes was measured with a spectrofluorometric method using Fura-2. Myocyte contractility was measured with a video edge system. NaHS (50 µM, an H2S donor) had no significant effect on the resting calcium level, electrically induced (EI) calcium transients, and cell contractility in ventricular myocytes. Stimulating endogenous NO production with l-arginine or exogenous application of NO donors [sodium nitroprusside (SNP) and 2-(N,N-diethylamino)-diazenolate-2-oxide] decreased myocyte twitch amplitudes accompanied by slower velocities of both cell contraction and relaxation. Surprisingly, NaHS reversed the negative inotropic and lusitropic effects of the above three NO-increasing agents. In addition, the mixture of SNP + NaHS increased, whereas SNP alone decreased, the resting calcium level and the amplitudes of EI calcium transients. Angeli's salt, a nitroxyl anion (HNO) donor, mimicked the effect of SNP + NaHS on calcium handling and myocyte contractility. Three thiols, N-acetyl-cysteine, l-cysteine, and glutathione, abolished the effects of HNO and SNP + NaHS on myocyte contraction. Neither Rp-cAMP [a protein kinase A (PKA) inhibitor] nor Rp-cGMP [a protein kinase G (PKG) inhibitor] affected the effects of SNP + NaHS, suggesting a cAMP/PKA- or cGMP/PKG-independent mechanism. Conclusion H2S may interact with NO to form a thiol sensitive molecule (probably HNO) which produces positive inotropic and lusitropic effects. Our findings may shed light on the interaction of NO and H2S and provide new clues to treat cardiovascular diseases. [ABSTRACT FROM PUBLISHER]

This study investigated the effects of Rehmannia glutinosa individually as well as in combination with the oral hypoglycemic agent, metformin in streptozotocin (STZ)-induced diabetic Wistar rats. R. glutinosa ethanolic extract was prepared and the constituents were characterized using fractionation by column chromatography, followed by high performance liquid chromatography-mass spectrometry. STZ (65 mg/kg) was injected intraperitoneally to induce diabetes in Wistar rats. The diabetic rats were divided into the following groups (each n = 6) and received the respective treatments for 30 days: (1) metformin (500 mg/kg), (2) R. glutinosa (200 mg/kg), (3) metformin (500 mg/kg) and R. glutinosa (200 mg/kg) and (4) diabetic control (DC). A reduction in plasma glucose levels caused by the herb was not as significant as metformin compared to the diabetic control (p < 0.05). However, R. glutinosa-treated group showed reductions in plasma C-reactive protein (CRP) levels compared to the diabetic controls (p < 0.05) as well as metformin-treated group (p < 0.05). An enhanced reduction in CRP concentration was observed in the group receiving both herb and metformin compared to metformin-treated group (p < 0.05). Reduction in CRP levels suggests an anti-inflammatory activity of the herb. [ABSTRACT FROM AUTHOR]

Oxidative stress is the root cause of diabetic macro- and microvascular complications. Biochemical and epidemiological studies indicate that current treatments for diabetes do not reduce risks of developing complications, suggesting their inability to alleviate the levels of oxidative stress. This study in streptozotocin (STZ)-induced diabetic rats was carried out to investigate the effect of combining the antidiabetic drug, metformin, with an ethanolic extract of Scutellaria baicalensis, a plant whose root is known for its radical scavenging activity. Three groups of STZ-induced diabetic rats were given the following treatments for 30 days: (1) metformin 500 mg/kg, (2) S. baicalensis 400 mg/kg, (3) metformin 500 mg/kg + S. baicalensis extract 400 mg/kg. In addition, vehicle-treated diabetic and nondiabetic controls were used in the experiment. The rats treated with S. baicalensis and metformin + S. baicalensis had elevated hepatic activities of the antioxidant enzymes — superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) compared to the vehicle- and metformin-treated diabetic groups (p < 0.05). Plasma and hepatic lipid peroxide concentrations in the herb-treated and herb + metformin-treated groups were also significantly reduced (p < 0.05). In addition, the combined treatment caused significant elevations of plasma and pancreatic insulin levels and reductions of plasma and hepatic triglycerides (TG) and cholesterol levels. The study thus showed that S. baicalensis enhanced the antidiabetic effect of metformin in STZ-induced diabetic rats by improving the antioxidant status. It also increased pancreatic insulin content as well as improved the lipid profile in these rats. [ABSTRACT FROM AUTHOR]

A novel approach to monitoring of mainstream smoke reactive oxygen species (ROS) has been developed and applied to the quantitation of smoke oxidants. Redox-active fluorescent probe dihydrorhodamine 6G (DHR-6G) was selected as the molecular probe because it is sensitive to typical smoke ROS. The experimental system couples an automatic cigarette smoke machine fiber-optic fluorometer for real-time monitoring of the reaction progress between cigarette smoke and DHR-GG. Quantitation was achieved based on the amount of rhodamine 6G, which is the sole product from DHR-6G oxidation. With the optimization of the trapping efficiency, we detected 391 nmol of ROS/cigarette in the mainstream CS for a standard cigarette 2R4F under standard Federal Trade Commission smoking protocol. Applying this method, we quantified the ROS of selected cigarettes and found that the cigarettes made of burley tobacco have much (~10 times) higher ROS content in the smoke than that in the tobacco made of bright tobacco. The smokeless cigarette, Eclipse, has comparable ROS with cigarettes made of bright tobacco. [ABSTRACT FROM AUTHOR]

Both MH(Ph)(CO)L2 (L=PtBu2Me; M = Ru and Os) react with vinyl fluoride to form M–F bonds; however, Ru eliminates benzene, while Os eliminates ethylene. In contrast, Ru(H)2(CO)L2 and Os(H)2(CO)(1-butene)L2 both react with vinyl fluoride to give ethylene and MHF(CO)L2. Ethylene production from both dihydrides is attributed to β-F migration to M from an MCH2CH2F transient, while the unique behavior of RuH(Ph)(CO)L2 (giving the C–F oxidative addition product Ru(η1-vinyl)F(CO)L2) is attributed to the difficulty of achieving RuIV, and the ability of the strongly π-acidic vinyl fluoride to rapidly trigger reductive elimination of benzene. The products of reaction of RuH(Ar)(CO)L2 with vinyl fluoride are redirected more towards ethylene formation when Ar carries fluorine substituents. The reaction products of OsH(R)(CO)L2 with vinyl fluoride revert to R-H elimination when R is methyl. Finally, the more π-acidic H2C＝CF2 triggers very rapid CH4 elimination from OsH(CH3)(CO)L2; cleavage of the second C–F bond yields the vinylidene OsF2(CCH2)(CO)L2. All selectivity is rationalized via the fate of the adduct MH(R)(C2H4− nFn)(CO)L2. [Copyright &y& Elsevier]

Examines the facile and reversible cleavage of carbon-fluorine bonds. Formation of the pentafluorophenyl and fluorocarbene complexes; Involvement of phosphine dissociation in the isomerization mechanism; Contrast between the behavior of osmium and ruthenium regarding the stability of fluoroalkyl and fluorocarbene.

Examines the structural distortions in mer-M(H)3(NO)L2 (M= ruthenium and osmium). Synthesis of ruthenium trihydrides and osmium trihydrides; Influence of the structural distortions of ruthenium and osmium trihydrides complexes on intramolecular fluxionality; Effects of intramolecular hydride exchange site on quantum exchange coupling.

Describes the reaction of 14-electron RuH(CO)L2+ with Me3SiCCPh that can be reversed to give a square-pyramidal coordination geometry. Silyl migration of Me3SiCCpH; Investigation via X-ray diffraction; Effect of lowering the temperature; Use of nuclear magnetic resonance.

Focuses on the health benefits of the dietary anti-oxidants found in the skin and seeds of fruits. Capability of anthocyanins, the plant pigments in flowers and fruits, to slow memory loss, reduce cancer cell proliferation and inhibit tumour formation; Functions of anti-oxidant compounds in fruits; Significance of the use of pigments from fruit as colouring agents.

An improved method for the measurement of oxygen radical absorbance capacity (ORAC) was developed and validated using fluorescein (3',6'-dihydroxyspiro[isobenzofuran-1[3H], 9'[9H]- xanthen]-3-one) as a new fluorescence probe (ORACFL). Randomly methylated ß-cyclodextrin (RMCD) was introduced as the water-solubility enhancer for lipophilic antioxidants. 7% RMCD (w/v) in 50% acetone-H2O mixture sufficiently solubilized vitamin E compounds and other lipophilic phenolic antioxidants in 75 mM phosphate buffer (pH 7.4). Results indicated that fluorescein shows excellent photostability under the plate reader conditions. This ORACFL was validated through linearity, precision, accuracy, and ruggedness. The validation results demonstrated that the ORACFL assay is reliable and robust. The mean of intraday and interday CVs were <15%; for hydrophilic ORAC, LOD and LOQ are 5 and 6.25 µM, respectively; for lipophilic ORAC, LOD and LOQ are 6.25 and 12.5 µM, respectively. It is concluded that unlike other popular methods, the ORACFL assay provides a direct measure of total antioxidant capacity against the peroxyl radicals. [ABSTRACT FROM AUTHOR]

The article provides a representation of energy-transfer-based photoluminescence (PL) nanoprobe for the detection of nitric oxide (NO). It mentions the use of molecular engineering of the superior optical properties of inorganic quantum dots (QDs) through iron complexes. It explains that the combination of the optical property of transition metal complexes and the fluorescent property of semiconductor QDs extends to novel probes for detecting reactive oxygen species and molecule ligands.