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PubMed2001

Fast determination of procyanidins and other phenolic compounds in food samples by micellar electrokinetic chromatography using acidic buffers.

Procyanidins are phenolic oligomers, mainly composed of (+)-catechin and (-)-epicatechin units that exhibit certain sensorial and physiological properties of interest (e.g., astringency and bitterness of food, antioxidant activity, etc.). This paper shows the development of a micellar electrokinetic chromatography (MEKC) method for the separation of three procyanidin dimers (B1, B2, and B3), their monomers ((+)-catechin and (-)-epicatechin), and the cis- and trans-forms of p-coumaric acid. Separation conditions are optimized in terms of buffer pH, SDS concentration, and washing routine between injections. The best results in terms of peak resolution and reproducibility between separations were obtained with a MEKC running buffer at pH 5 with 100 mM SDS and a washing routine that includes a rinse step with 0.1 M sodium hydroxide. Using this new MEKC method it is possible to separate in less than 5 min the seven substances. More interestingly, it is demonstrated that the low pH used in this MEKC method allows one to obtain clean electropherograms when samples are injected. The method is shown to be reproducible between different days with relative standard deviation (RSD) values lower than 1% for migration times and lower than 7% for peak areas (3 days, 24 injections). The usefulness of this procedure to determine these compounds in effluents from food processing (i.e., soaking water from lentils, white beans and black beans) and in food by-products (i.e., almond peels) considered as potential procyanidin sources is demonstrated. To our knowledge, this is the first report of separation and determination of procyanidins in food samples done by capillary electrophoresis.

Biflavonoids↗
PubMed2002

New perspectives on taste and primate evolution: the dichotomy in gustatory coding for perception of beneficent versus noxious substances as supported by correlations among human thresholds.

In various environments where primates are presently observed, as well as in forests and savannas which have been inhabited by australopithecines and early hominids, there are (or there have been presumably) categories of substances eliciting taste signals associated with stereotyped responses. Such is the case for various soluble sugars of fruits and nectars, attracting consumers, and for several plant compounds in which bitter or strongly astringent properties have a repulsive effect. The occurrence of such classes of tasty substances among natural products appears to be related to the evolutionary trends that shaped primate sensory perception (for detecting either beneficent or potentially noxious substances) in the context of a long history of coevolution between animals and plants. Here, we present original psychophysical data on humans (412 individuals aged 17-59 years) as an analogy with which to test recent evidence from electrophysiology in nonhuman primates (Hellekant et al. [1997] J. Neurophysiol. 77:978-993; Danilova et al. [1998] Ann. N.Y. Acad. Sci. 855:160-164) that taste fibers can be grouped into clusters of "best-responding fibers" with two more specific clusters, one for sugars and one for quinine and tannins. The collinearity found between human taste responses (recognition thresholds) for fructose and sucrose, as well as for quinine and tannins, is presented and discussed as another evidence of the two-direction evolutionary trend determining taste sensitivity. Salt perception appears to be totally independent of these trends. Accordingly, the appreciation of a salty taste seems to be a recent culturally learned response, and not a primary taste perception. The very existence of primary tastes is discussed in the context of evolutionary trends, past and present.

Adolescent↗
PubMed2004

Removal of phenolic compounds in pomegranate juices using ultrafiltration and laccase-ultrafiltration combinations.

Phenolic compounds of fruit juices are responsible for haze and sediment formation as well as for color, bitterness and astringency. The influence of ultrafiltration (UF) and laccase-UF combination was investigated on phenolic contents of pomegranate juices and on filtration output. Laccase-treated and then ultrafiltered pomegranate juices have shown a rapid increase in their color, when compared to only ultrafiltered (control) samples. Kinetic parameters of laccase were also determined. During the oxidation period, the changes occurring in pomegranate juices were estimated from phenolic contents, color and anthocyanin measurements. Results have shown that laccase oxidation produced a significant decrease in phenolic content of pomegranate juices while juice color the increased. However, in recent literatures, the possibility to remove polyphenols in apple juices was reported. We decided in this study that laccase treatment can not be applied due to the loss of natural red color and unwanted dark brownish color formation in pomegranate juice.

Antioxidants↗
PubMedDate not supplied

Mass spectrometry in grape and wine chemistry. Part I: polyphenols.

Mass spectrometry, had and still has, a very important role for research and quality control in the viticulture and enology field, and its analytical power is relevant for structural studies on aroma and polyphenolic compounds. Polyphenols are responsible for the taste and color of wine, and confer astringency and structure to the beverage. The knowledge of the anthocyanic structure is very important to predict the aging attitude of wine, and to attempt to resolve problems about color stability. Moreover, polyphenols are the main compounds related to the benefits of wine consumption in the diet, because of their properties in the treatment of circulatory disorders such as capillary fragility, peripheral chronic venous insufficiency, and microangiopathy of the retina. Liquid Chromatography-Mass Spectrometry (LC-MS) techniques are nowadays the best analytical approach to study polyphenols in grape extracts and wine, and are the most effective tool in the study of the structure of anthocyanins. The MS/MS approach is a very powerful tool that permits anthocyanin aglycone and sugar moiety characterization. LC-MS allows the characterization of complex structures of grape polyphenols, such as procyanidins, proanthocyanidins, prodelphinidins, and tannins, and provides experimental evidence for structures that were previously only hypothesized. The matrix-assisted-laser-desorption-ionization-time-of-flight (MALDI-TOF) technique is suitable to determine the presence of molecules of higher molecular weight with high accuracy, and it has been applied with success to study procyanidin oligomers up to heptamers in the reflectron mode, and up to nonamers in the linear mode. The levels of resveratrol in wine, an important polyphenol well-known for its beneficial effects, have been determined by SPME and LC-MS, and the former approach led to the best results in terms of sensitivity.

Agriculture↗
PubMed2006

Evaluation of phytoconstituents of Terminalia arjuna for wound healing activity in rats.

The effect of topical application of phytoconstituents (fraction I, II and III) fractionated from a hydroalcohol extract of the bark of the plant, Terminalia arjuna, was assessed on the healing of rat dermal wounds using in vivo models. The results indicated a statistically significant increase in the tensile strength of the incision wounds and the percent epithelialization of excision wounds compared with control (p < 0.05). However, topical treatment with fraction I, consisting mainly of tannins, was found to demonstrate a maximum increase in the tensile strength of incision wounds. Even with respect to excision wounds, the fastest rate of epithelialization was seen with fraction I. Hexosamine estimation of granulation tissue obtained from excision wounds revealed an increase in the hexosamine content with fraction I compared with the control. In addition, fraction I from the hydroalcohol extract of Arjuna bark possessed antimicrobial activity against tested microorganisms such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes but not Candida albicans. These results strongly document the beneficial effects of fraction I, consisting mainly of tannins, of Terminalia arjuna in the acceleration of the healing process. Thus, the present study validates the claim made with respect to the plant as well as corroborating the astringent effect of tannins by drawing the tissues closer together.

Animals↗
PubMed1998

Determinants of the thirst-quenching character of beer.

The purpose of this study was to find which sensory characteristics are significant determinants of the thirst-quenching character of beer. The sensory attributes and thirst-quenching characteristics ("thirst quenching", "refreshing", "drinkability") of 18 beers were evaluated by a panel of 12 judges. The only significant positive determinants of the "thirst-quenching" character of the beers in the design were carbonation and bubble density. Significant negative determinants were foam, overall aroma and flavor, color, viscosity, malty, hoppy, burnt, bitterness, acidic, metallic, astringency and aftertaste. The same correlations (both in terms of direction and significance level) were observed between descriptive attributes and the "refreshing" and "drinkability" factors. A principal component analysis (PCA) of the mean ratings indicated that variability among beers was mostly along a thirst-quenching dimension (72% of the variance). Procrustes analysis performed on the individual ratings showed that, for one of the judges, the interpretation of the thirst-quenching concept differed from that shown by PCA for the overall panel.

Adult↗
PubMed1998

Effect of processing on phenolics of wines.

Phenolics of grapes are the main compounds responsible for color, taste, mouth feel, oxidation and other chemical reactions in wine and juice. Phenolic levels in wine and juice are affected by numerous processing conditions (crushing, pressing, sulfite addition, skin contact, oak aging). Studies were conducted to better understand the effect of processing on phenolic composition of three varieties of grapes. Three different processing steps: immediate press, hot press, and hull treatment (skin contact) for 7 and 14 days were applied to three different grape varieties, Vitis rotundifolia cv. Noble, Vitis vinifer cv. Cabernet Sauvignon, and the French-American hybrid Chambourcin. Phenolic compounds were identified and quantified by High Performance Liquid Chromatography (HPLC) and bitterness/astringency were assessed using a trained sensory panel. V. rotundifolia wines had higher levels of epicatechin and gallic acid but lower caftaric acid and procyanidins compared to the other varieties and were more astringent and bitter. Processing treatment affected phenolics and color differently among the three varieties.

Beverages↗
PubMed1989

Moral medicine: symbolic content in 19th century Shaker therapeutics.

This paper presents an analysis of the symbolic meanings implicit in an ostensibly empirical therapeutic system. The Shakers, a celibate communal religious order founded in New York State in the mid 1770s, were practitioners of botanic medicine, as were many other Americans in the nineteenth century. This study analyzes the therapeutic properties of the herbs they produced (such as diuretic, stimulant, narcotic, emetic, astringent), using a classification scheme based on the location of the botanical substance's effect vis-à-vis body boundaries and surfaces. The Shakers' beliefs about the therapeutic properties of their herbs are compared with similar analyses of the properties given by two contemporary nineteenth century New England proponents of herbal medicine, botanist Constantine Rafinesque and sectarian practitioner Samuel Thomson. The comparison shows systematic variation in emphasis given to herbs which regulate internal body processes, or act through the openings of the body or on its surface. In this context Shaker medicine can be characterized as quickening, internal, and purifying in its effects on body processes, effects which are highly consistent with Shaker religious beliefs in active, physical worship, selflessness and spiritual purification by confession.

Body Image↗
PubMed1989

The use of an alum irrigation in the treatment of massive bladder haemorrhage.

Severe, massive bladder haemorrhage is a difficult and often frustrating clinical problem. The aetiologies are numerous and include irradiation, malignancy, severe infection and drug-induced changes. Among the numerous modalities of treatment that have been reported formalin, phenol and silver nitrate instillations have often been associated with significant side effects, morbidity and mortality and have had varying degrees of success. During the last two years we have used continuous closed irrigation of a sterile 0.5% alum solution in 16 patients. Alum is an astringent and acts by protein precipitation over the bleeding surface. Because of a low cell permeability its action is limited to the cell surface and interstitial spaces. The permeability of the cell membrane is reduced but remains viable. The preparation and the pharmaceutical aspects of the 0.5% alum irrigation will be discussed. The conclusion is that the technique of managing massive bladder haemorrhage is simple, efficient, nontoxic and less expensive than previously reported therapies. Therefore, irrigation with alum before instituting invasive means to control bleeding is recommended.

Aged↗
PubMed2005

Application of microencapsulated isoflavone into milk.

This study was designed to develop a microencapsulated, water-soluble isoflavone for application into milk and to examine the hypocholesterolemic effect of such a milk product in a rat diet. The coating material was medium-chain triglyceride (MCT) and the core material was water-soluble isoflavone. The microencapsulation efficiency was 70.2% when the ratio (w/w) of coating material to core material was 15:1. The isoflavone release from the microcapsules was 8% after 3-day storage at 40 degrees C. In in vitro study, 4.0-9.3% of water-soluble isoflavone in simulated gastric fluid was released in the pH range of 2 to 5 after 60 min incubation; however, in simulated intestinal fluid at pH 8, 87.6% of isoflavone was released from the capsules after 40 min incubation time. In sensory analysis, the scores of bitterness, astringency, and off-taste in the encapsulated isoflavone-added milk were slightly, but not significantly, different from those in uncapsulated, isoflavone-added milk. In blood analysis, total cholesterol was significantly decreased in the isoflavone-added group compared with that in the control after 6-week feeding. Therefore, this study confirmed the acceptability of MCT as a coating material in the microencapsulation of water-soluble isoflavone for application into milk, although a slight adverse effect was found in terms of sensory attributes. In addition, blood total cholesterol was lowered in rats which had been fed a cholesterol-reduced and microencapsulated, isoflavone-added milk for 6 weeks.

Animals↗
PubMed2003

Factors affecting in vitro bond strength of bonding agents to human dentin.

Four generations of total-etch (fourth, fifth) and self-etching (sixth, seventh) bonding agents for use with resin composites are commercially available in the United States. Innovations in bonding agents include: filled systems, release of fluoride and other agents, unit dose, self-cured catalyst, option of etching with either phosphoric acid or self-etching primer, and pH indicators. Factors that can affect in vitro bond strength to human dentin include substrate (superficial dentin, deep dentin; permanent versus primary teeth; artificial carious dentin), phosphoric acid versus acidic primers, preparation by air abrasion and laser, moisture, contaminants, desensitizing agents, astringents, and self-cured restorative materials. This article reviews studies conducted at the Houston Biomaterials Research Center from 1993 to 2003. Results show that in vitro bond strengths can be reduced by more than 50% when bonding conditions are not ideal.

Composite Resins↗
PubMed2002

Increase in tannin consumption by sifaka ( Propithecus verreauxi verreauxi) females during the birth season: a case for self-medication in prosimians?

In this study we report preliminary data on the consumption of tannin-rich plants by sifakas (Propithecus verreauxi verreauxi) living in the Kirindy forest, western Madagascar. Sifakas spent most of their time feeding on only a few plant species. The tannin intake during the period between the pregnancy and birth season was significantly higher in pregnant females or females with lactating infants than in non-reproductive females and males. These periparturient females secured a larger proportion of condensed tannins by short feeding bouts on plants not included in the group's limited preferred food species. The measured increase in tannin intake is puzzling in light of the fact that tannins are commonly known for their protein-binding properties. Since protein demands are highest in pregnant and lactating females, possible medicinal benefits of tannin ingestion are considered. Tannin consumption is associated with an increase in body weight and stimulation of milk secretion. Veterinarians administer tannins as an astringent, anti-hemorrhagic and anti-abortive. Their high potential as an alternative anthelminthic has also recently been recognized. Thus, when viewed as self-medicating behavior, controlled increase in tannin intake could have multiple prophylactic advantages for females during the periparturient period. The high selectivity in their plant choice, and the presence of unusual feeding habits by a particular group of individuals (females with infants) limited in time (birth season), suggests that an increase in tannin ingestion may be a self-medicating behavior with multiple directly adaptive benefits to female reproduction.

Animals↗
PubMed2005

The role of taste in food selection by African apes: implications for niche separation and overlap in tropical forests.

Ripe fruit eating shapes the behavior of most of the apes. Gorillas (Gorilla gorilla) and chimpanzees (Pan troglodytes) are very different sizes and, consequently, have been traditionally viewed as ecologically distinct, but few studies have explored the behavioral and physiological foundations of their diets. Debate continues on the extent that large-bodied gorillas may be less selective and more opportunistic fruit eaters than chimpanzees. Taste responses have been predicted to relate to body size and digestive strategies. This study employs laboratory research on taste perception and discrimination among captive zoo-housed chimpanzees and relates it to previous work on gorillas to better characterize diets and niche separation among these apes. During the captive trials, differences were recorded in consumption patterns of water and varying concentrations of dilute aqueous fructose (sweet) and tannic acid solutions (astringent), compounds commonly found in wild foods. The chimpanzees exhibited similar preference thresholds for fructose (50 mM) to other primates studied. They exhibited slightly lower inhibition thresholds for tannic acid solutions than gorillas, but higher than smaller primates studied to date. These preliminary findings suggest that tannin tolerance may well be mediated by body size, though possible species differences in salivary proteins or other sensory differences remain to be explored. This research furthers our efforts to understand the roles of body size and physiological adaptations in shaping diet and niche separation of chimpanzees and gorillas.

Animals↗
PubMed1996

[Bath additives in dermatologic balneotherapy. Indications and approaches in current research].

Progress in dermatological research during the last years has provided new insights into the mode of action of additives to dermatological baths. The present paper reviews the pharmacokinetics of dermatological bath therapy additives such as sulfur, salts and trace elements, tars and ichthyol, lipids, antiseptics, astringents, plant extracts, surface-active agents and proteins.

Balneology↗
PubMed2005

Characterization of condensed tannins purified from legume forages: chromophore production, protein precipitation, and inhibitory effects on cellulose digestion.

To identify simple screening tools for selecting condensed tannin (CT)-containing forages as candidate sources for further study, CT were isolated from nine legumes, and their molecular weights (MW), chromophore production, capacity to precipitate bovine serum albumin (BSA) and Fraction 1 protein (Rubisco) isolated from alfalfa, and inhibition of filter paper digestion were compared. Sources were as follows: leaves of sericea lespedeza (Lespedeza cuneata Dum.-Cours.), crown vetch (Coronilla varia L.), and sainfoin (Onobrychis viciifolia Scop.); stems of hedysarum (Hedysarum alpinum L.); seeds of alfalfa (Medicago sativa L.); and whole plants of birdsfoot trefoil (Lotus corniculatus var. corniculatus L.) and three varieties of big trefoil (Lotus pedunculatus Cav.), viz., Lotus uliginosus Schkuhr, L. uliginosus var. glabriusculus, and L. uliginosus var. villosus. Molecular weights and sizes (degrees of polymerization) of the CT varied considerably within and among plant species. Average MW ranged from 3036 Da (crown vetch) to 7143 Da (lespedeza). All CT exhibited greater capacity (w/w basis) to bind alfalfa Rubisco than BSA. Relative astringencies (microg CT required to precipitate 1 mg protein) against BSA ranged from 262.5 for CT from lespedeza to 435.5 for CT from L. corniculatus, and against Rubisco, from 49.6 (sainfoin) to 108.2 (alfalfa seed). Including CT at 300 microg/ml in cultures of Fibrobacter succinogenes reduced digestion of cellulose filter paper by 19.8% (sainfoin) to 92.4% (crown vetch) and increased the specific activity of cell-associated endoglucanase. There were no correlations between inhibitory effects of CT on filter paper digestion and (1) chromophore formation during CT assay by butanol-HCl, vanillin-HCl, or H2SO4; (2) precipitation of BSA or alfalfa Rubisco; and (3) MW of CT. The most inhibitory CT for cellulose digestion included those with broad and with narrow MW distributions. Sainfoin was the most desirable source of CT, as it had the highest capacity to bind alfalfa protein and was least inhibitory to cellulose digestion by F. succinogenes. This study suggests that these properties are not easily defined via chemical means, and that biological assays using rumen bacteria may help identify those CT with properties of nutritional interest.

1-Butanol↗
PubMed1985

Review and survey of medicaments used with gingival retraction cords.

Data from a survey of 495 dentists indicate that most dentists used the mechanical-chemical method of gingival-deflection; 79.39% of those used cord containing epinephrine. It can be concluded that potentially significant amounts of epinephrine can be absorbed systemically from the local anesthetic solution, that secretion of endogenous epinephrine in response to stress occurs, often at levels sufficient to cause measurable changes in hemodynamic variables, and that absorption of epinephrine from impregnated strings occurs. The amount of absorption will vary with the exposure of the vascular bed, the length and concentration of the impregnated cord, and the length of time of application. It is possible that the actual total amount of circulating catecholamine would be cumulative, and the corresponding cardiovascular response would be related to the total amount of epinephrine in the bloodstream, regardless of the source. When the fact that we usually have inadequate data on the cardiovascular status of our patients is considered, as well as the tendency to make impressions of multiple prepared teeth, the continued use of epinephrine cord in dentistry must be viewed with alarm. Equally effective astringent gingival deflection agents such as alum, aluminum sulfate, and aluminum chloride exert no systemic effects. Therefore, there is little indication for use of epinephrine-containing retraction cords. Adequate medical evaluation, careful use of anesthetics that contain epinephrine, and sedative techniques when indicated will assure the safety of our patients.

Adult↗
PubMed1982

Antibacterial activity of gutta-percha cones attributed to the zinc oxide component.

Growth of several species of bacteria was inhibited by the presence of endodontic gutta-percha cones. Microbiologic analysis, measurement of osmolarity, microscopy, x-ray diffraction analysis, and scanning electron micrography were used to identify the biologically active component that slowly leaches from gutta-percha cones. This component is zinc oxide in the form of small solid particles, from which active, soluble Zn2+ ion is mobilized by hydrolysis. A hypothesis on the "depot" effect of the ZnO particles is formulated, and is used to discuss some earlier reported literature on toxic and antibacterial activity of zinc oxide-containing materials. It is concluded that zinc oxide is not to be considered an inert compound. Its widespread uses in medicine and dentistry seem to reside in its "inert," biocompatible, and astringent properties mainly. The biologically active role of zinc oxide, however, merits further investigation.

Bacteria↗
PubMed1993

Preference and aversion for deterrent chemicals in two species of Peromyscus mouse.

Deterrent chemicals such as quinine hydrochloride (QHC1) are generally considered to be aversive to mammals at all detectable concentrations. However, several species contain individuals that drink solutions containing low concentrations of deterrents in preference to plain water. The present study examines this paradoxical preference in two species of mouse, Peromyscus melanotis and P. aztecus. Preliminary findings had suggested that whereas some P. aztecus prefer low concentrations of QHC1, no P. melanotis prefer any concentration of QHC1. Experiment 1 tested the hypothesis that individual mice that prefer low concentrations of QHC1 would respond similarly to four other deterrents described by humans as bitter and/or astringent (ouabain, hop extract, sucrose octaacetate, and tannic acid) in 48-h, two-bottle choice tests. Peromyscus aztecus displayed a large amount of intraspecific variation in response to all five deterrents. Those P. aztecus that drank low concentrations of QHC1 in preference to plain water were significantly more likely to respond similarly to low concentrations of the other deterrents. No P. melanotis displayed a preference for any concentration of either deterrent. Experiment 2 examined the temporal stability of the response to 0.1 mM QHC1 in P. aztecus over six consecutive choice tests. Mice were divided into three groups based on their initial response to the QHC1 solution (preference, no response, or rejection) and then subjected to the 12-day test. The response of mice within each of the groups did not change significantly over time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗