SEARCH · Search PubMed

Results for “Astringents”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources

PubMed1994

Is the bitter rejection response always adaptive?

The bitter rejection response consists of a suite of withdrawal reflexes and negative affective responses. It is generally assumed to have evolved as a way to facilitate avoidance of foods that are poisonous because they usually taste bitter to humans. Using previously published studies, the present paper examines the relationship between bitterness and toxicity in mammals, and then assesses the ecological costs and benefits of the bitter rejection response in carnivorous, omnivorous, and herbivorous (grazing and browsing) mammals. If the bitter rejection response accurately predicts the potential toxicity of foods, then one would expect the threshold for the response to be lower for highly toxic compounds than for nontoxic compounds. The data revealed no such relationship. Bitter taste thresholds varied independently of toxicity thresholds, indicating that the bitter rejection response is just as likely to be elicited by a harmless bitter food as it is by a harmful one. Thus, it is not necessarily in an animal's best interest to have an extremely high or low bitter threshold. Based on this observation, it was hypothesized that the adaptiveness of the bitter rejection response depends upon the relative occurrence of bitter and potentially toxic compounds in an animal's diet. Animals with a relatively high occurrence of bitter and potentially toxic compounds in their diet (e.g., browsing herbivores) were predicted to have evolved a high bitter taste threshold and tolerance to dietary poisons. Such an adaptation would be necessary because a browser cannot "afford" to reject all foods that are bitter and potentially toxic without unduly restricting its dietary options. At the other extreme, animals that rarely encounter bitter and potentially toxic compounds in their diet (e.g., carnivores) were predicted to have evolved a low bitter threshold. Carnivores could "afford" to utilize such a stringent rejection mechanism because foods containing bitter and potentially toxic compounds constitute a small portion of their diet. Since the low bitter threshold would reduce substantially the risk of ingesting anything poisonous, carnivores were also expected to have a relatively low tolerance to dietary poisons. This hypothesis was supported by a comparison involving 30 mammal species, in which a suggestive relationship was found between quinine hydrochloride sensitivity and trophic group, with carnivores > omnivores > grazers > browsers. Further support for the hypothesis was provided by a comparison across browsers and grazers in terms of the production of tannin-binding salivary proteins, which probably represent an adaptation for reducing the bitterness and astringency of tannins.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1987

Detection of dengue virus RNA using nucleic acid hybridization.

Conditions for using slot-blot nucleic acid hybridization to quantitatively detect dengue-2 virus using a radiolabelled cDNA probe, pVV17, were determined. As little as 11 plaque-forming units of virus were detected using a hybridization mixture without formamide and performing the test at 70 degrees C. While predominantly serotype-specific using stringent (65 degrees C) washing conditions, the probe detected all four dengue virus serotypes using astringent (28 degrees C) washing conditions. No significant qualitative differences were detected using Thai dengue-2 viruses isolated over a 10-year period. High titered, anti-flavivirus antibodies blocked virus detection by an antigen capture, enzyme-linked, immunosorbent assay or by intrathoracic inoculation of Toxorhyncites mosquitoes, but not by nucleic acid hybridization. The appearance of virus-specified RNA coincided with the detection of antigen in infected C6/36 (Aedes albopictus) cells by immunofluorescence, or in cell culture supernatants by the antigen capture method. The method has potential as a diagnostic tool for identifying dengue viruses in clinical and field specimens.

Animals↗

PubMed1985

Anti-inflammatory actions of tannins isolated from the bark of Anacardium occidentale L.

A mixture of tannins (hydrolysable and non-hydrolysable) obtained from the bark of Anacardium occidentale L., on i.p. injection, demonstrated apparent anti-inflammatory activity in carrageenan- and dextran-induced rat paw oedemas, cotton pellet granuloma test and adjuvant-induced polyarthritis in rats. At higher doses orally administered tannins also had activity in carrageenan paw oedema and adjuvant arthritis experiments. The tannins i.p. also inhibited acetic acid-induced "writhing responses" in mice and were found to antagonise the permeability-increasing effects in rats of certain mediators of inflammation and to inhibit the migration of leucocytes to an inflammatory site. While not appearing to act by the release of adrenal hormones, tannins may produce effects in a non-specific manner by their astringent properties on cell membranes thus affecting cell functions. The above results should be considered while studying the anti-inflammatory actions of plant extracts which contain tannins.

Animals↗

PubMed1991

Xanthine oxidase inhibitory activity of Chilean Myrtaceae.

Twenty-one Myrtaceae collections belonging to 10 species, 5 of which are used in Chilean folk medicine, were assayed for inhibitory activity towards the enzyme xanthine oxidase. Most leaf and stem extracts were devoid of activity or showed a weak inhibitory effect. Chilean ethnobotanical data on the species are linked to the astringent properties of Myrtaceae and their use for treating wounds and diarrhea. The results show the advantage of using proper plant selection criteria when searching for new drugs to treat human gout.

Chile↗

PubMed1992

Indigenous phytotherapy of gastrointestinal disorders in a lowland Mixe community (Oaxaca, Mexico): ethnopharmacologic evaluation.

Gastrointestinal disorders are one of the major health problems in developing countries. Sixty-five plants used popularly in the treatment of such disorders in a Mixe Indian community in Oaxaca (Mexico) and collected during a fieldstudy of 15 months are described. According to indigenous criteria a plant is used in the treatment of a certain illness because of the plant's characteristic smell and taste. Plants with astringent properties are particularly valued to treat diarrhoea and dysentery. Bitter, aromatic and bitter-aromatic plants are especially employed to treat gastrointestinal cramps and pain. Additionally, the efficacy of these plants was evaluated using ethnobotanical, phytochemical and pharmacologic information on the plants. The majority of the plants contain chemicals that may produce the effects desired by the Mixe. Frequently tannin-containing drugs are used to treat diarrhoea and dysentery. A large number of the plants used by the Mixe in the treatment of gastrointestinal pain contain essential oil or bitter principles. As a result of this evaluation, plants were selected which should be studied phytochemically and pharmacologically with priority, to evaluate further their potential in the treatment of gastrointestinal disorders.

Diarrhea↗

PubMed2005

Treatment for axillary osmidrosis with suction-assisted cartilage shaver.

Axillary osmidrosis is a common and distressing social problem for many. Topical astringents are temporary and inadequate. Permanent solutions often involve invasive surgical treatment. This study is to evaluate the effectiveness and advantages of treating axillary osmidrosis with suction-assisted cartilage shaver. Eighty-nine patients with osmidrosis were treated with suction-assisted cartilage shaver under local anesthesia on an outpatient basis. Patients were followed-up and surveyed for satisfaction with surgery by completing a questionnaire. Of the 89 patients, 82 patients (92.1%) expressed positive satisfaction with the procedure. In the elimination of odour, a total of 81 patients (91.0%) ranked good to excellent, and seven patients (7.9%) expressed fair results. All of the 89 patients (100%) detected the clearing of wound induration within 3 months. Eighty patients (89.9%) felt their arms were back in full range of movement within 1 month, and all had such hindrance resolved within 2 months. Thus, the procedure proved itself a promising treatment for the removal of sweat glands with advantages of a short operation time, inconspicuous scar, and a rapid recovery for returning to daily activities.

Adolescent↗

PubMed2005

Analysis of polymeric phenolics in red wines using different techniques combined with gel permeation chromatography fractionation.

A multiple-step analytical method was developed to improve the analysis of polymeric phenolics in red wines. With a common initial step based on the fractionation of wine phenolics by gel permeation chromatography (GPC), different analytical techniques were used: high-performance liquid chromatography-diode array detection (HPLC-DAD), HPLC-mass spectrometry (MS), capillary zone electrophoresis (CZE) and spectrophotometry. This method proved to be valid for analyzing different families of phenolic compounds, such as monomeric phenolics and their derivatives, polymeric pigments and proanthocyanidins. The analytical characteristics of fractionation by GPC were studied and the method was fully validated, yielding satisfactory statistical results. GPC fractionation substantially improved the analysis of polymeric pigments by CZE, in terms of response, repeatability and reproducibility. It also represented an improvement in the traditional vanillin assay used for proanthocyanidin (PA) quantification. Astringent proanthocyanidins were also analyzed using a simple combined method that allowed these compounds, for which only general indexes were available, to be quantified.

Chemical Fractionation↗

PubMed2005

Elimination of bitter, disgusting tastes of drugs and foods by cyclodextrins.

The bitter taste of drugs, food components, and any other substances which get in the mouth as dissolved in an aqueous solution, or in the saliva, can be strongly reduced or fully eliminated, if the bitter component forms an inclusion complex with an appropriate cyclodextrin (CD). The value of the complex association constant (determined by the structure of the bitter 'guest' molecule and the size and eventual substitution of the 'host' CD molecule), the temperature and the host/guest ratio determine the extent of complexation of the guest molecule (percentage of complexation) at the equilibrium. The K(ass) for most drug/CD complexes at 36 degrees C buccal cavity temperature is between 10(2) and 10(4) mol-1. If the unit dose (of a sublingual or chewing tablet, chewing gum) with a bitter drug (molecular weight of about 150, forming a 1:1 complex with betaCD) is approximately 10mg then the betaCD can be taken in a 5- or even 10-fold molar excess. Under such conditions more than 99% of the bitter drug is complexed, and because complexed molecules cannot react with the taste buds in the buccal cavity no bitter taste is perceived. Frequently, preparation of the drug/CD complex is not necessary, because the betaCD is present in a large excess, dissolved very quickly in the saliva and results in a saturated CD solution. Therefore, the complexation of the bitter drug is completed very rapidly. Only dissolved substances have taste and only CD complexable drug molecules can become debittered by CDs. Bitter, astringent components of foods (e.g. soya), beverages (e.g. naringin in citrus fruit juice, or chlorogenic acid and polyphenols in coffee) cigarette smoke (nicotine) also can be complexed and their taste reduced or fully eliminated.

Cyclodextrins↗

PubMed2026

Flavoromics-based profiling reveals taste and aroma differences between infant formula and breast milk.

Flavor differences between infant formula (IF) and breast milk (BM) are considered a potential factor affecting infants' acceptance of IF. This experiment employs flavoromics combined with multivariate statistical analysis to systematically compare the flavor profiles of IF and BM. Electronic tongue analysis and amino acid correlation revealed that IF was characterised by pronounced saltiness and umami richness, whereas BM exhibited greater bitterness and astringency. Volatile compound profiling identified five key flavor constituents in IF, predominantly aldehydes such as hexanal and pentanal. In contrast, BM contained a broader array of compounds-including acids, aldehydes, and esters-resulting in a more complex flavor profile. Kyoto Encyclopedia of Genes and Genomes (KEGG)-based metabolic pathway annotation, together with fatty acid profiling, suggested that some volatiles may be associated with lipid oxidation, Maillard reaction and sulfur-containing amino acid degradation pathways, offering a theoretical basis for the targeted optimisation of IF flavor.

Humans↗

PubMed2026

Enhancement flavor quality in Zhao'an Baxian oolong tea through enhanced turning-over process.

A systematical investigation on the effects of turning-over intensity on the flavor formation of Zhao'an Baxian oolong tea (ZBT) was performed, through a comparative analysis of heavy turning-over (HT) and light turning-over (LT) treatments in this study. The tea samples were subjected to proteomic and metabolomic analyses, combined with quantitative descriptive analysis (QDA) and electronic sensory (E-tongue/E-nose) evaluation. The results demonstrate that HT significantly reduced the content of bitter and astringent compounds, such as catechins and flavonol glycosides, while promoting the accumulation of umami-related amino acids. Concurrently, HT enhanced the biosynthesis of key floral and fruity volatiles, such as β-ocimene, geraniol, benzaldehyde, jasmone by activating stress-responsive metabolic pathways. These coordinated biochemical changes, driven by enzyme-catalyzed reactions in response to prolonged mechanical wounding and environmental stress, collectively improved the overall sensory profile of ZBT. These findings provide a mechanistic foundation for improving ZBT production, with clear implications for quality control and flavor-oriented product development.

Tea↗

PubMed2004

Tannase activity by lactic acid bacteria isolated from grape must and wine.

We examined a range of oenological lactic acid bacteria species and reference strains for their potential to degrade tannins. Bacterial tannase activity was checked by a spectrophotometric and a visual reading method. None of the strains belonging to the oenological species of the genus Lactobacillus, Leuconostoc, Oenococcus or Pediococcus were tannase producers, with the exception of Lactobacillus plantarum. All the L. plantarum strains analyzed were positive for tannase activity and their identities were reconfirmed by L. plantarum PCR-specific assay or by sequencing the 16S rDNA. Tannase activity could be considered an important criterion for the selection of malolactic starter cultures since it might confer advantages in the winemaking process by reducing astringency and haze in wine.

Base Sequence↗

PubMed2006

The microbiology of Ghanaian cocoa fermentations analysed using culture-dependent and culture-independent methods.

Export of cocoa beans is of great economic importance in Ghana and several other tropical countries. Raw cocoa has an astringent unpleasant taste and a spontaneous fermentation is the first step in a process leading to cocoa beans with the characteristic cocoa flavour and taste. The microbiology of Ghanaian cocoa fermentations was investigated using culture-dependent and culture-independent methods. Samples were collected at 12 hour intervals during 96-144 hour tray and traditional heap fermentations. Yeast, Lactic Acid Bacteria (LAB), Acetic Acid Bacteria (AAB) and Bacillus spp. were enumerated on suitable substrates and identified using phenotypic and molecular methods. The yeast and bacterial micro-populations involved in the cocoa fermentation were further investigated using the culture-independent method Denaturing Gradient Gel Electrophopresis (DGGE). A microbiological succession was observed during the fermentations. At the onset of fermentation yeasts were the dominating microorganisms. Lactic Acid Bacteria became dominant after 12-24 h of fermentation and remained predominant throughout the fermentations with AAB reaching high counts in the mid phase of fermentation. Bacillus spp. were only detected during heap fermentations where they reached high numbers during the later stages of fermentation. Hanseniaspora guilliermondii was the predominant yeast during the initial phase and Pichia membranifaciens during the later phases of fermentation. A number of other yeast species including three putatively undescribed species were isolated during the fermentations. Lactobacillus fermentum was the dominant LAB in most samples. Several other LAB including Lactobacillus plantarum, Leuconostoc pseudomesenteroides, Leuconostoc pseudoficulneum, Pediocococcus acidilactici and a putatively undescribed LAB species were detected during the fermentations. Acetobacter syzygii, Acetobacter pasteurianus and Acetobacter tropicalis were the predominant AAB in all investigated fermentations. During the later stages of heap fermentation Bacillus licheniformis and occasionally other Bacillus spp. were detected in high numbers. In general the culture-based findings were confirmed using DGGE. However, DGGE indicated that Lc. pseudoficulneum plays a more important role during the fermentation of cocoa than expected from the culture-based findings as it yielded a strong band in most DGGE fingerprints. Cluster analysis of the DGGE fingerprints revealed that the DGGE fingerprints clustered according to fermentation site. Within each fermentation site the profiles clustered according to fermentation time. The DGGE method seems to offer a relatively fast and reliable tool for studying yeast and bacterial dynamics during cocoa fermentations.

Bacteria↗

PubMed2004

Evaluation of bottled nutritive drinks using a taste sensor.

The purpose of this study was to evaluate the taste of 20 bottled nutritive drinks, all commercially available on the Japanese market, both in human gustatory sensation tests and using a multi-channel taste sensor. In the gustatory sensation tests, seven trained healthy volunteers were asked to score the drinks in terms of the intensities of four basic tastes (sweetness, saltiness, sourness, and bitterness), for overall palatability (ease of drinking), and for nine components of palatability (astringency, pungency, fruitiness, tasting of a medicinal plant, refreshing, irritating to the throat, seeming beneficial, good aftertaste, and the desire to drink again). The data were analysed to determine the critical factors for overall palatability. There was a positive linear correlation between overall palatability and 'sourness', 'fruitiness', 'refreshing', and 'good aftertaste' scores (r = 0.79, 0.85, 0.74, and 0.70, respectively). There was a negative correlation between overall palatability and 'bitterness intensity', 'tasting of a medicinal plant', 'seeming beneficial', and 'pungency' scores (r = -0.76, -0.64, -0.62, and -0.50, respectively). When evaluated using a multi-channel taste sensor, there was a positive linear correlation between the intensities of sourness and bitterness determined by the human volunteers and those predicted by the taste sensor (r = 0.85 and 0.71, respectively). The pungency intensity, as evidenced in gustatory sensation tests, could be also predicted by sensor output (r = 0.84). The taste sensor seems therefore to be a potentially useful tool in evaluating the palatability of bottled nutritive drinks.

Beverages↗

PubMed2006

Sensory characteristics of beverages prepared with commercial thickeners used for dysphagia diets.

OBJECTIVE: To describe and compare sensory characteristics of six beverages prepared with four commercial thickeners used in dysphagia diets. DESIGN: The study used a completely randomized design within a test of each beverage. SUBJECTS/SETTING: Five highly trained descriptive sensory analysis panelists conducted the testing in a laboratory environment. INTERVENTION: Coffee, milk, apple juice, orange juice, Ensure (Abbott Laboratories, Abbott Park, IL), and water were thickened using two starch-based and two gum-based commercial thickeners according to manufacturers' instructions to achieve nectar-like and honey-like consistencies. MAIN OUTCOME MEASURES: Sensory attributes of the original beverages and the thickened samples were defined and scored. STATISTICAL ANALYSES PERFORMED: Sensory scores were analyzed by analysis of variance using general linear models and Fisher's least significant difference test to determine specific differences. RESULTS: All thickeners suppressed the main flavors of the base beverages and imparted slight off-flavors (bitter, sour, metallic, or astringent) in some beverages. Starch-based thickeners imparted a starchy flavor and grainy texture, whereas gum-based thickeners gave added slickness to the beverages. Although thickeners mixed well with some beverages, they were difficult to disperse in others, making some thickened beverages lumpy. CONCLUSIONS: All thickeners added either a starchy, grainy, or slick flavor or texture and tended to suppress the base flavor of beverages, especially at honey-like consistencies. Thus, individual decisions about which characteristics are more negative (eg, slick vs grainy texture) for specific patients must be made. Additional development of thickening agents seems necessary for improved sensory properties. Information from this article should help professionals and their patients with dysphagia better understand the sensory issues associated with the use of commercial thickening agents in various beverages.

Analysis of Variance↗

PubMed2005

Effect of Salvia officinalis L. leaves on serum glucose and insulin in healthy and streptozotocin-induced diabetic rats.

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 hypoglycaemic effect of sage leaves, we investigated the effects of essential oil and methanolic effect of the plant on healthy and streptozotocin-induced diabetic rats. The animals were made diabetic using by streptozotocin (70 mg/kg, i.p.). The methanolic extract (100, 250, 400 and 500 mg/kg) and essential oil (0.042, 0.125, 0.2 and 0.4 ml/kg) were injected intraperitoneally. The control groups were administered water and sunflower oil as vehicles of methanolic extract and essential oil, respectively. Blood samples were obtained from retro-orbital sinus before administration and 1, 3 and 5 h after administrations. The serum glucose was measured by the enzymatic method of glucose oxidase. The results showed that the essential oil of sage did not change serum glucose, while the plant extract significantly decreased serum glucose in diabetic rats in 3h without effect on insulin releasing from the pancreas but not in healthy rats. Also, the LD(50) of the methanolic extract is measured (4000 mg/kg, i.p.). The present data indicate that sage extract has hypoglycaemic effect on diabetic animals and the plant should be considered in future therapeutic researches.

Animals↗

PubMed2005

Pomegranate as a cosmeceutical source: pomegranate fractions promote proliferation and procollagen synthesis and inhibit matrix metalloproteinase-1 production in human skin cells.

Pomegranate (Punica granatum) is an ancient fruit with exceptionally rich ethnomedical applications. The peel (pericarp) is well regarded for its astringent properties; the seeds for conferring invulnerability in combat and stimulating beauty and fertility. Here, aqueous fractions prepared from the fruit's peel and fermented juice and lipophilic fractions prepared from pomegranate seeds were examined for effects on human epidermal keratinocyte and human dermal fibroblast function. Pomegranate seed oil, but not aqueous extracts of fermented juice, peel or seed cake, was shown to stimulate keratinocyte proliferation in monolayer culture. In parallel, a mild thickening of the epidermis (without the loss of ordered differentiation) was observed in skin organ culture. The same pomegranate seed oil that stimulated keratinocyte proliferation was without effect on fibroblast function. In contrast, pomegranate peel extract (and to a lesser extent, both the fermented juice and seed cake extracts) stimulated type I procollagen synthesis and inhibited matrix metalloproteinase-1 (MMP-1; interstitial collagenase) production by dermal fibroblasts, but had no growth-supporting effect on keratinocytes. These results suggest heuristic potential of pomegranate fractions for facilitating skin repair in a polar manner, namely aqueous extracts (especially of pomegranate peel) promoting regeneration of dermis, and pomegranate seed oil promoting regeneration of epidermis.

Cell Proliferation↗

PubMed2005

Protective and antioxidant effects of Rhizophora mangle L. against NSAID-induced gastric ulcers.

The bark of Rhizophora mangle, the red mangrove, has been used traditionally in folk medicine of Caribbean countries due to its antiseptic, astringent, haemostatic and antifungal properties. Aqueous extracts are rich in tannins and have been proven experimentally to possess antibacterial, wound healing and antiulcerogenic effects. This work was designed to determine the gastroprotective effect of Rhizophora mangle in a model of diclofenac-induced ulcers in rats and to study the mechanisms involved, using the proton pump inhibitor omeprazole as a comparison. The lyophilized extract was given by oral gavage (125 and 62.5mg/kg) three times at 12h intervals before administering diclofenac 100mg/kg. Pretreatment with the extract resulted in a significant decrease of the ulcerated area (P<0.01). Rhizophora mangle induced a recovery of PGE(2) levels, which had been depleted by diclofenac. No anti-inflammatory effect was observed ex vivo or in vitro. The highest dose of the extract provoked a marked increase in glutathione peroxidase and superoxide dismutase activity, which was comparable to omeprazole. Furthermore, lipid peroxidation levels were inhibited in a dose-dependent manner. These results suggest that the gastroprotective effect of Rhizophora mangle in this experimental model appears through an antioxidant and prostaglandin-dependent way.

Animals↗

PubMed2005

Comparative pharmacognostic studies of three Phyllanthus species.

Different species of Phyllanthus are considered to be very effective hepatoprotective agents in the Indian indigenous systems of medicine and are considered bitter, astringent, stomachic, diuretic, febrifuge, deobstruant and antiseptic. Still ayurvedic practitioners prescribed fresh juice of 'Bhuiamlki' for jaundice. Various species of Phyllanthus are being sold in India under the trade name 'Bhuiamlki'. During market surveillance of herbal drug, it was observed that almost all the commercial samples, either comprise of Phyllanthus amarus Schum & Thonn. or Phyllanthus maderaspatensis Linn. or mixture of Phyllanthus amarus, Phyllanthus fraternus Webster. and Phyllanthus maderaspatensis. Therefore, in this context the detailed pharmacognostical evaluation of all the three species has been carried out with the aim to establish the identification markers of this important hepatoprotective agent (effective in hepatitis B too). The study conclude that all the three species can be differentiated on the basis of macro and microscopic characters, physico-chemical values, HPTLC fingerprint profile, and detection of phyllanthin and hypophyllanthin as marker components. Besides, an interesting conclusion can also be drawn that phyllanthin and hypophyllanthin said to protect hepatocytes against carbon tetrachloride and galactosamine induced toxicity, may not be exclusively responsible for hepatoprotective activity as these are present only in Phyllanthus amarus while Phyllanthus fraternus and Phyllanthus maderaspatensis also possess significant hepatoprotective activity.

Phyllanthus↗