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At least 163 records · Page 9Linked to original sources
PubMed2006

Effects of Salvia officinalis L. (sage) leaves on memory retention and its interaction with the cholinergic system in rats.

OBJECTIVE: The leaves of sage (Salvia officinalis L., Lamiaceae) are reported to have a wide range of biological activities, such as anti-bacterial, fungistatic, virustatic, astringent, eupeptic and anti-hydrotic effects. To determine the mnemogenic effect of sage leaves, we investigated the effects of ethanolic extract of sage leaves and its interaction with cholinergic system on memory retention of passive avoidance learning in rats. METHODS: Post-training intracerebroventricular (i.c.v.) injections were carried out in all the experiments except ethanolic extract (i.p. intraperitoneally). RESULTS: Administration of ethanolic extract (50 mg/kg), pilocarpine (0.5 and 1 mg/rat), the muscarinic cholinoceptor agonist, and nicotine (0.1 and 1 microg/rat) increased, while mecamylamine (1, 5 microg/rat), the muscarinic cholinoceptor antagonist, and mecamylamine (0.01 and 0.1 microg/rat), the nicotine cholinoceptor antagonist decreased memory retention in rats. Activation of muscarinic cholinoceptors by pilocarpine potentiated the response of ethanolic extract. Also, pharmacological blockade of scopolamine attenuated potentiating effect of ethanolic extract. Activation of nicotinic cholinoceptor by nicotine potentiated the response of ethanolic extract. Blockade of nicotinic cholinoceptor by mecamylamine attenuated the response of ethanolic extract. CONCLUSION: It is concluded that the ethanolic extract of salvia officinalis potentiated memory retention and also it has an interaction with muscarinic and nicotinic cholinergic systems that is involved in the memory retention process.

Andorra↗
PubMed2006

Overexpression and characterization of two human salivary proline rich proteins.

Proline rich proteins (PRP) are among major human saliva constituents and are known to interact with wine tannins that are involved in astringency. To characterize these interactions, a human salivary proline rich pro-protein, PRB4S, was overexpressed in Pichia pastoris. Six recombinant proteins resulting from maturation in bioreactor were detected by SDS-PAGE analysis between 15 and 45 kDa (apparent molecular weight). Two of them, the 45 and the 15 kDa ones, were isolated from culture supernatant by adsorption and permeation chromatography. They were characterized by N-terminal sequencing and MALDI-TOF analysis after trypsic digestion. The 45 kDa protein is glycosylated while the 15 kDa one was obtained after a furin-like proteolysis. Both of them are similar to human whole saliva PRP resulting from proteolysis of PRB4S pro-protein in Golgi network and known as II-1 and IB-5. Because of their sensitivity to proteolysis or their unusual mobility on SDS-PAGE gel, these recombinant proteins seem to be intrinsically unstructured proteins.

Glycosylation↗
PubMed2000

Effects of Lactobacillus strains on the ripening and organoleptic characteristics of Arzúa-Ulloa cheese.

Seven batches of Arzúa-Ulloa, a short-ripened soft cow's milk cheese produced in Galicia (NW Spain), were prepared from pasteurized milk. Two control batches of cheese (CB) were made with an acid-aromatic starter containing Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. lactis var. diacetylactis, isolated from raw-milk Arzúa-Ulloa cheeses. Five batches of cheese (LB) were made with the acid-aromatic starter plus one of five strains of mesophilic homofermentative Lactobacillus spp.: four of them isolated from raw-milk Arzúa-Ulloa cheese (characterized in previous works) and the remaining was a commercial Lactobacillus strain. Higher counts of mesophilic viable bacteria, lactic acid bacteria and citrate-fermenting bacteria were found on days 1 or 15 of ripening, while higher counts of lactobacilli were found on day 30 of ripening. On day 1 of ripening the highest diacetyl-acetoin content was noted in the CB, but after day 15 the diacetyl-acetoin content was similar or higher in three of the five LB. The mean degradation of beta-casein in CB was higher than in LB, while the degradation of alpha(s1)-casein was higher in LB. The mean contents of nitrogen-soluble fractions were slightly higher in the LB than in the CB. Volatile free fatty acid (VFFA) contents were, in general, greater in LB than in CB and maximum amounts were determined on day 15 of maturation. Sensorial analysis indicated a more acid taste was in LB, while bitter and astringent tastes were more intense in CB. A positive correlation was found between beta-casein degradation and bitter taste. Yogurt and butter aromas were more intense in CB and in two of the five LB. Firmness was lower in LB and a negative correlation was found between this parameter and alpha(s1)-casein degradation. Crumbliness showed a positive correlation with beta-casein degradation. The use of the Lactobacillus strains assessed in this study is recommended for Arzúa-Ulloa cheese manufacture, in order to enhance the desirable characteristics of this cheese variety, i.e., a soft texture due to alpha(s1)-casein proteolysis but without the bitter taste due to beta-casein degradation and a spicy and slightly rancid aroma and taste.

Acetoin↗
PubMed2001

Camelliin B induced apoptosis in HeLa cell line.

Gordonia axillaris (Roxb.) Dietrich (Theaceae) is a native to Taiwan and the leaves have been used as an astringent folk medicine. Camelliin B (CB), a macrocyclic hydrolyzable tannin, was isolated from G. axillaris and showed cytotoxic effects in human carcinoma cells. Among the target cells (SKHep-1, Ha-22T, DU-145, AGS, and HeLa), the cervical carcinoma cell line, HeLa, was more sensitive to CB than were Chang normal liver cells and primary-cultured normal gingival and cervical fibroblasts. Furthermore, the cytotoxic effects of CB showed dose-dependency at 3.2-100.0 microg/ml in HeLa for 1,24,48, and 72 h and with an IC(50) value of 46.3 microg/ml for 48 h. However, the IC(50) value of CB in primary-cultured normal cervical fibroblasts was 108.0 microg/ml. Therefore, the selectivity shown by CB was ascribed to the difference in growth speed between normal and tumor cells. HeLa cells and primary-cultured normal cervical fibroblasts were treated with 50.0 and 100.0 microg/ml CB for 48 h, respectively, and exhibited chromatin condensation, indicating the occurrence of apoptosis. Flow cytometric analysis demonstrated the presence of apoptotic cells with low DNA content, a decrease of cell population at the G(1) phase, and a concomitant increase of cell population at the G(2)/M phase. CB also caused DNA fragmentation and inhibited PARP degradation in HeLa cells. However, CB did not significantly inhibit Bcl-2 expression in HeLa cells at 50.0 microg/ml, only at 100.0 microg/ml for 48 h. These results suggest that CB induced apoptosis, without direct inhibition of Bcl-2 expression in HeLa cells.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Prediction of the bitterness of single, binary- and multiple-component amino acid solutions using a taste sensor.

The purpose of this study was to develop a quick, quantitative, prediction method for the determination of the bitterness of solutions containing one or more of five amino acids (L-isoleucine, L-leucine, L-valine, L-phenylalanine, and L-tryptophan), using an artificial taste sensor. The bitterness of various solutions containing different concentrations (1, 3, 10, 30, and 100 mM) of five amino acids, singly and in combination, was estimated using a multichannel taste sensor and compared with the results of human gustatory sensation tests with nine volunteers. The relative response electric potential patterns were similar for all five amino acids. Large sensor outputs were observed in channels 1-4 (which are negatively charged) while there were no responses in channels 5-8 (positively charged). The sensor output for channel 1, which was the largest output value, was used for prediction of bitterness. The change of membrane potential caused by adsorption (CPA), which corresponds to aftertaste, could not be used as an explanatory variable since the adsorption of the amino acids to the sensor membrane was weak and CPA values were small. The bitterness intensity scores for single, binary, and multi-component amino acid solutions, could be easily predicted on the basis of the sensor output value of channel 1 using regression analysis. Principal component analysis of the sensor output data suggested that the sourness, astringency and/or smell of the solutions also played a role in the perception of bitterness.

Amino Acids↗
PubMed1999

Effect of protease inhibitors on the sense of taste.

The purpose of this study was to investigate the taste properties of protease inhibitors which are essential components of drug regimes used to treat human immunodeficiency virus (HIV) infection. In this study, the taste properties of four protease inhibitors (indinavir, ritonavir, saquinavir, and nelfinavir) were investigated in unmedicated HIV-infected patients and healthy controls. Three of the four protease inhibitors (indinavir, ritonavir, and saquinavir) were found to be predominantly bitter (with additional qualities of medicinal, metallic, astringent, sour, and burning). Nelfinavir was found to be relatively tasteless. HIV-infected and uninfected control subjects detected protease inhibitors at similar concentrations, but HIV-infected subjects perceived suprathreshold concentrations as more bitter than controls. Detection thresholds ranged from 0.0061 mM for saquinavir in HIV-infected patients to 0.0702 mM for ritonavir in uninfected control subjects. Suprathreshold studies indicated that protease inhibitors modified the taste perception of a variety of other taste compounds. These results are consistent with clinical findings that protease inhibitors produce taste complaints that can impact patient compliance.

Adult↗
PubMedDate not supplied

Effect of the nucleoside analogs zidovudine, didanosine, stavudine, and lamivudine on the sense of taste.

The purpose of this study was to investigate the taste properties of nucleoside analogs, which are among the current medications used to treat human immunodeficiency virus (HIV) infection. Eighteen unmedicated HIV-positive subjects and 41 healthy control subjects participated in threshold and suprathreshold experiments. All of the nucleoside medications tested were perceived as predominantly bitter (along with other qualities such as metallic, medicinal, sour, astringent, and cooling). The nucleoside analog with the lowest detection thresholds was zidovudine; the detection threshold was 1.47 mM for HIV-infected patients and 2.15 mM for control subjects. Detection thresholds for lamivudine were 4.41 mM for HIV-infected patients and 4.36 mM for control subjects. Detection thresholds for stavudine were 6.39 mM for HIV-infected patients and 5.99 mM for control subjects. Detection thresholds for didanosine were 14.29 mM for HIV-infected patients and 24.0 mM for control subjects. The nucleoside analogs also modified the taste perception of KCl and CaCl2. There were no significant differences between HIV-infected subjects and control subjects for detection threshold values for any of the drugs. However, HIV-infected subjects rated lamivudine, zidovudine, and stavudine as significantly more bitter than did the control subjects at concentrations four times higher than their detection thresholds. This result was not due to use of medications by HIV-infected subjects because none of the subjects (neither HIV-infected nor control) were taking medications.

Adult↗
PubMed2003

Three-dimensional structure and dynamics of wine tannin-saliva protein complexes. A multitechnique approach.

The interactions between the B3 (catechin-4alpha,8-catechin) red wine tannin and the human salivary protein fragment IB7(14) (SPPGKPQGPPPQGG) were monitored by (1)H magic angle spinning NMR, circular dichroism, electrospray ionization mass spectrometry, and molecular modeling. It is found that the secondary structure of IB7(14) is made of a type II helix (collagen helix) and random coil. The central glycine 8 appears to act as a flexible rotula separating two helix II regions. Three tannin molecules tightly complex the peptide, without modifying its secondary structure, but seem to reduce its conformational dynamics. The binding dissociation constant is in the millimolar range. B3 tannins with a "tweezers" conformation bind to the hydrophilic side of the saliva peptide, suggesting that the principal driving forces toward association are governed by hydrogen bonding between the carbonyl functions of proline residues and both the phenol and catechol OH groups. These findings are further discussed in the frame of an astringency phenomenon.

Anthocyanins↗
PubMed1997

Multiple interactions between polyphenols and a salivary proline-rich protein repeat result in complexation and precipitation.

Polyphenols (tannins) in the diet not only precipitate oral proteins, producing an astringent sensation, but also interact with dietary proteins and digestive enzymes in the gut, resulting in a variety of antinutritive and toxic effects. Salivary proline-rich proteins (PRPs), which are secreted into the oral cavity, form complexes with and precipitate dietary polyphenols, and thus, they constitute the primary mammalian defense directed against ingested tannins. In order to characterize the interaction, NMR studies were performed which involved titrating a series of polyphenols into a synthetic 19-residue PRP fragment. The results show that the predominant mode of association is a hydrophobic stacking of the polyphenol ring against the pro-S face of proline and that the first proline residue of a Pro-Pro sequence is a particularly favored binding site. Measurement of dissociation constants indicates that the larger and more complex polyphenols interact more strongly with the PRP fragment; the order of binding affinity was determined as procyanidin dimer B-2 > pentagalloylglucose > trigalloylglucose >> proanthocyanidin monomer (-)-epicatechin approximately propyl gallate. Smaller polyphenols can bind with one phenolic ring stacked against each proline residue, whereas larger polyphenols occupy two or three consecutive prolines. The more complex polyphenols interact with the PRP fragment in a multidentate fashion; moreover, they self-associate or stack when bound. Thus, a model is proposed in which multiple polyphenol/polyphenol and polyphenol/PRP interactions act cooperatively to achieve precipitation.

Amino Acid Sequence↗
PubMed2002

Multiple conformations of the proline-rich protein/epigallocatechin gallate complex determined by time-averaged nuclear Overhauser effects.

The structure of the complex between the heptapeptide Gln-Gly-Arg-Pro-Pro-Gln-Gly and the polyphenol (-)-epigallocatechin gallate (EGCG) has been determined using time-averaged nuclear Overhauser effects. Effective parameters for the force constant and time constant have been derived, allowing rapid and efficient calculation of structures that satisfy the input restraints. By using multiple start conformations, it is shown that conformational space is covered adequately and that the complex exists in one major conformation, in which the A ring of the EGCG is positioned over Pro5 and the D ring is over Pro4, with the B ring frequently close to the arginine side chain. Alternative conformations are also found, in which the prolines are almost always both involved in stacking interactions, with a strong preference for Pro4 to be involved. The structures are consistent with previous models for the interaction and suggest how precipitation of the complex could occur, which leads to the oral phenomenon of astringency. The method has promise as a general way of docking ligands onto receptors.

Amino Acid Sequence↗
PubMed2001

Influence of aging conditions on the quality of red Sangiovese wine.

A red Sangiovese wine was stored in barrels of different woods (oak and chestnut) and types (225-L "barriques" and 1000-L barrels) at 12 and 22 degrees C for 320 days to evaluate the effects of different aging conditions on wine quality. Chestnut barrels led to wines richer in phenolics, and which were more tannic, colored, and fruity. Oak barrels gave wines with more monomeric phenolics, but less astringent, with higher vanilla smell, and more harmonious. The type of barrel could be used as a parameter to regulate the extraction of wood components and the polymerization of monomeric phenolics. Storage at 22 degrees C favored the formation of polymerized phenolics and the increase of color density and color hue. The temperature produced less pronounced effects on aroma and taste, even if wines stored at 12 degrees C showed more harmony.

Aging↗
PubMed2001

New flavanol derivatives from grape (Vitis vinifera) byproducts. Antioxidant aminoethylthio-flavan-3-ol conjugates from a polymeric waste fraction used as a source of flavanols.

A new family of antioxidants has been obtained from a residual fraction of polymeric polyphenols of grape origin. The integral exploitation of resources is important in any sustainable production scheme. Many byproducts and residues generated by the agroindustries contain polyphenols with potential application as preventative agents against cancer and cardiovascular diseases. Among these polyphenols oligomeric proanthocyanidins are particularly significant. The polymeric forms, considered of less interest because of their astringent properties, constitute the largest portion of the biologically active plant proanthocyanidins. The new compounds described here result from the breakdown of polymeric flavanols in the presence of cysteamine and bear an amino function, which facilitates their isolation from complex mixtures by cation-exchange gels or resins. In this way, valuable antioxidant molecules can be efficiently obtained from otherwise wasted polymers. The new molecules appear to be as effective as their underivatized counterparts (flavan-3-ols) as antioxidants.

Antioxidants↗
PubMed2002

Changes in proanthocyanidin chain length in winelike model solutions.

Reactions of seed and skin proanthocyanidins in the presence or absence of (-)-epicatechin were followed in winelike solutions over 53 days at 30 degrees C. Proanthocyanidins were separated from flavanol monomers by sequential elution from a Sep Pak cartridge, and changes in proanthocyanidin composition were monitored by thiolysis analysis of the proanthocyanidin fraction. In solutions containing no free (-)-epicatechin, trace amounts of monomers were released and important losses of proanthocyanidins were measured, but their average composition and mean degree of polymerization (mDP) were hardly modified. In the presence of (-)-epicatechin, the mDP value decreased and oligomeric proanthocyanidins accumulated throughout the incubation while losses of total units were dramatically reduced. Our data indicate that interflavanic bond cleavage of proanthocyanidins occurred under mild acidic conditions such as encountered in wine and that the resulting carbocation proceeded to unknown species. The latter reaction did not take place in the presence of (-)-epicatechin. Epicatechin added to the intermediate carbocation, thus being incorporated as the end unit of a shorter proanthocyanidin chain. The results of this study are discussed in relation to the loss of astringency reported during wine aging.

Anthocyanins↗
PubMed2002

Chemical composition and flavor of ecuadorian cocoa liquor.

The contribution of the chemical composition to the flavor of cocoa liquor from an Ecuadorian selfed population of clone EET 95 was investigated. Polyphenols, purine alkaloids, organic acids, and sugars were quantified, and the key sensory characteristics of cocoa were scored by a trained panel. Despite the short bean fermentation (2 days) commonly used for Arriba cocoa, acetic acid content was closely correlated to liquor pH, demonstrating its essential role in cocoa liquor acidification. Polyphenols were positively correlated to astringency, bitterness, and the green note and negatively correlated to the fruity character. Alkaloid and polyphenol levels fluctuated significantly within the selfed progeny and tended to be lower than those of the heterozygous clone EET 95 (inbreeding effect). These results support the idea that polyphenols might be essential to the overall perception of cocoa liquor characteristics and indicate that the composition and the sensory quality of cocoa liquor are the result of both a genotypic contribution and the conditions of fermentation and roasting.

Acetic Acid↗
PubMed2003

Microencapsulated iron for milk fortification.

This study was designed to develop a microencapsulated iron that could be used to fortify milk and to determine the sensory properties of milk fortified with microencapsulated iron. Coating material was polyglycerol monostearate (PGMS), and selected core material was ferric ammonium sulfate. The highest efficiency of microencapsulation was 75% with 5:1:30 ratio (w/w/v) as coating to core materials to distilled water. Iron release was 12% when stored at 4 degrees C for 3 days. The TBA value was the lowest when 100 ppm of capsulated iron was added into milk and was significantly lower in capsulated groups compared with that in uncapsulated groups. In an in vitro study, only 3-5% of iron was released in simulated gastric fluid (pH 3, 4, 5, and 6). Comparatively, iron release increased dramatically from 12.3% (pH 5) to 95.7% (pH 8) for 60 min of incubation in simulated intestinal fluid. In a sensory analysis, most aspects except for metallic taste and color were not significantly different between control and capsulated iron fortified milk at 3 days of storage. However, between capsulated and uncapsulated groups, astringency, metallic, color, and overall scores were significantly different. The present study indicated that the use of microencapsulated iron with PGMS is effective for fortifying milk.

Animals↗
PubMed2003

Flavoring components of raw monsooned arabica coffee and their changes during radiation processing.

Volatile aroma principles, nonvolatile taste constituents (caffeine and chlorogenic and caffeic acids), and glycosidically bound aroma compounds of monsooned and nonmonsooned raw arabica coffee were analyzed using gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). Among the most potent odor active constituents known to contribute to the aroma of the green beans, 3-isopropyl-2-methoxypyrazine, 3-isobutyl-2-methoxypyrazine, 4-vinylguaiacol, beta-damascenone, (E)-2-nonenal, trans,trans-2,4-decadienal, phenylacetaldehyde, and 3-methylbutyric acid were detected by GC-MS in both samples. A decrease in content of methoxypyrazines and an increase in 4-vinylguaiacol and isoeugenol resulted in a dominant spicy note of monsooned coffee. These phenolic compounds exist partly as their glycosides, and their release from the bound precursors during monsooning accounted for their higher content in monsooned coffee. A considerable decrease in astringent chlorogenic acid as a consequence of hydrolysis to bitter caffeic acid was noted in monsooned coffee. Radiation processing of nonmonsooned beans at a dose of 5 kGy resulted in an increased rate of monsooning. At this dose a quantitative increase in most of the aroma active components could be observed in all samples studied. Hydrolysis of chlorogenic acid to caffeic acid was noted in radiation-processed monsooned coffee beans irrespective of whether the treatment was carried out before or after monsooning. These changes were, however, not observed in irradiated, nonmonsooned coffee beans, suggesting an enzymatic rather than a radiolytic cleavage of chlorogenic acid. A rationale behind the mechanism of monsooning and radiation-induced enhancement of the monsooning process is discussed.

Caffeic Acids↗
PubMed2004

Screening for antioxidant activity in edible plant products: comparison of low-density lipoprotein oxidation assay, DPPH radical scavenging assay, and Folin-Ciocalteu assay.

Oxidation of low-density lipoprotein (LDL) has been implicated in atherogenesis. Antioxidants that prevent LDL from oxidizing may reduce atherosclerosis. This study investigated LDL antioxidant activity in edible plant products for development of dietary supplementation to prevent atherosclerosis. Fifty-two kinds of edible plants were extracted using 70% aqueous ethanol solution, and the antioxidant activity of the extracts, which inhibit human LDL oxidation induced by copper ion, was determined on the basis of the oxidation lag time and represented as epigallocatechin 3-gallate equivalent. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and total phenolic content were also measured for comparisons with antioxidant activity in LDL. Plant products showing the greatest activity in LDL oxidation assay were akamegashiwa (Mallotus japonicus) leaf, Japanese privet (Ligustrum japonicum) leaf, green tea [Camellia sinensis (L.) O. Kuntze], and astringent persimmon (Diospyros kaki). The present study revealed high levels of LDL antioxidant activity in plant products for which such activity levels are underestimated in the DPPH radical scavenging assay and Folin-Ciocalteu assay.

Antioxidants↗
PubMed2004

Polyphenolic profiles of Basque cider apple cultivars and their technological properties.

The polyphenolic compositions of 31 Basque cider apple cultivars were determined in pulp, peel, and juice by high-performance liquid chromatography with diode array detection analysis of crude extracts and after thiolysis. Total polyphenols are distributed in a wide concentration range depending on the cultivar. Procyanidins are the class of polyphenols that present major concentrations in apple. Their average degrees of polymerization range from 4 to 8 depending on the cultivar. Apple cultivars were technologically classified into bitter and nonbitter categories using different classification systems obtained by applying several pattern recognition techniques, such as principal component analysis, K-nearest neighbors, soft independent modeling of class analogy, partial least-squares, and multilayer feed-forward-artificial neural networks, to apple pulp, peel, or juice data (individual polyphenol concentrations, total procyanidin content, and the average degree of polymerization of procyanidins). Bitter apple cultivars present higher contents of flavan-3-ols and/or dihydrochalcones than nonbitter cultivars. Detailed knowledge of the polyphenolic profile of each apple cultivar affords information about their susceptibility to oxidation, their sensory properties (bitterness, astringency), and their possible influence on the characteristics and quality of the final product (juice, cider) when apples are processed.

Beverages↗