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At least 271 records · Page 15Linked to original sources
PubMed1993

A novel fine granule system for masking bitter taste.

In order to prepare fine granules of sparfloxacin (SPFX), a new quinolone anti-bacterial drug that shows masking of the bitter taste of SPFX and dissolutes at a rapid rate, various film-coated fine granules containing 20% SPFX and 0-52% low-substituted hydroxypropylcellulose(L-HPC) in the cores, were prepared by a spray method. Mixtures of ethylcellulose (EC), hydroxypropylmethylcellulose (HPMC), titanium dioxide and sucrose stearate in weight ratios of X:Y:2:1 (X + Y = 6) were used as film materials. The degree of masking of the bitter taste by water-insoluble film, mainly consisting of EC and HPMC, increased by increasing the content ratio of EC to HPMC and the amount of films, but was also slightly affected by the amount of L-HPC in the cores, which were coated with either EC or EC/HPMC (4/2). On the other hand, the dissolution rate increased with an increased amount of L-HPC in the cores and with a decreasing ratio of EC to HPMC in the films. Increasing the amount of L-HPC in the cores, which induced a considerable expansion of the fine granules owing to their taking up of water from the dissolution medium, resulted in bursting of the film after a short lag time. The bioavailability of the film-coated fine granules containing 20% SPFX and 52% L-HPC in the cores and 10% EC/HPMC (4/2) in the coating film, which masked the bitter taste of SPFX and showed the optimal release characteristics, was equivalent to that of conventional tablets containing 100 mg SPFX in beagle dogs.

Animals↗
PubMed1999

The marked inhibition of the bitter taste of Polymyxin B sulfate and trimethoprim x sulfamethoxazole by flavored BMI-60 in pediatric patients.

Taste acceptability of ground Polymyxin B sulfate and Bactramin C tablets was examined when flavored BMI-60, a food additive, was added. Both adult and child volunteers found the bitter taste of the two drugs markedly inhibited, making it clinically useful. Noncompliance, due to this bitterness, was improved using flavored BMI-60. The most striking characteristic of flavored BMI-60 is the ease of preparation compared with the manufacture of other hospital pharmaceuticals such as jelly, gummi and candy done to mask bitterness.

Adult↗
PubMed2004

Suppression of the bitterness of enteral nutrients using increased particle sizes of branched-chain amino acids (BCAAs) and various flavours: a taste sensor study.

An improved formulation of the enteral nutrient Aminoleban EN (Otsuka Pharmaceutical Co., Ltd., Tokyo, Japan), has been commercially available since Spring 2004. Like the previous formulation, the improved product contains branched-chain amino acids (BCAAs) L-isoleucine (L-Ile), L-leucine (L-Leu), and L-valine (L-Val), but the average particle size of these amino acids has been increased to 180 to 250 microm in the improved formulation, compared with 40 to 90 microm in the old product. The improved formulation has a significantly lower bitterness intensity score than the older formulation, as evaluated both in human gustatory tests and using the artificial taste sensor. We propose that this improved taste masking is due to the larger particle size of the BCAA crystals, due to which their release rates are reduced. The addition of improved flavours has also helped to reduce the bitterness of the improved Aminoleban EN formulation significantly. Analysis of the taste sensor data suggests that the sourness and sweetness of the added flavours were critical in diminishing the bitterness of Aminoleban EN.

Amino Acids, Branched-Chain↗
PubMed2005

Induction of interferon-gamma (IFN-gamma) and T helper 1 (Th1) immune response by bitter gourd extract.

Mice were inoculated intraperitoneally wih 34 different types of vegetable juices, and interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) were measured as markers for the induction of Th1 and Th2 cells, respectively. Serum IFN-gamma level was markedly increased in mice inoculated with bitter gourd (Momordica charantia) juice, but IL-4 levels were not increased with any of the 34 vegetable juices. Testing of the various components of bitter gourd, including peel, pulp, and seed, showed that the pulp induced the highest levels of IFN-gamma. Trial immunogen including the heat extract of the pulp induced specific IgG(2a) antibody of the mice serum inoculated with this immunogen. These results demonstrate that bitter gourd pulp induced IFN-gamma production and show its promise as a means of effective immunostimulatory therapy specific for Th1 cells and IFN-gamma production.

Animals↗
PubMed2006

Bitter gourd (Momordica Charantia): A dietary approach to hyperglycemia.

Bitter gourd (Momordica charantia) is a vegetable with pantropical distribution. It contains substances with antidiabetic properties such as charantin, vicine, and polypeptide-p, as well as other unspecific bioactive components such as antioxidants. Metabolic and hypoglycemic effects of bitter gourd extracts have been demonstrated in cell culture, animal, and human studies. The mechanism of action, whether it is via regulation of insulin release or altered glucose metabolism and its insulin-like effect, is still under debate. Adverse effects are also known. Nevertheless, bitter gourd has the potential to become a component of the diet or a dietary supplement for diabetic and prediabetic patients. Well-designed interdisciplinary research by nutritionists, medical doctors, and agronomists is needed before a dietary recommendation can be given and a product brought to the market.

Animals↗
PubMed2006

Temporal coding mediates discrimination of "bitter" taste stimuli by an insect.

The mechanisms that mediate discriminative taste processing in insects are poorly understood. We asked whether temporal patterns of discharge from the peripheral taste system of an insect (Manduca sexta caterpillars; Sphingidae) contribute to the discrimination of three "bitter" taste stimuli: salicin, caffeine, and aristolochic acid. The gustatory response to these stimuli is mediated exclusively by three pairs of bitter-sensitive taste cell, which are located in the medial, lateral, and epipharyngeal sensilla. We tested for discrimination by habituating the caterpillars to salicin and then determining whether the habituation generalized to caffeine or aristolochic acid. We ran habituation-generalization tests in caterpillars with their full complement of taste sensilla (i.e., intact) and in caterpillars with ablated lateral sensilla (i.e., lat-ablated). The latter perturbation enabled us to examine discrimination in caterpillars with a modified peripheral taste profile. We found that the intact and lat-ablated caterpillars both generalized the salicin-habituation to caffeine but not aristolochic acid. Next, we determined whether this pattern of stimulus-generalization could be explained by salicin and aristolochic acid generating distinct ensemble, rate, temporal, or spatiotemporal codes. To this end, we recorded excitatory responses from the bitter-sensitive taste cells and then used these responses to formulate predictions about whether the salicin-habituation should generalize to caffeine or aristolochic acid, separately for each coding framework. We found that the pattern of stimulus generalization in both intact and lat-ablated caterpillars could only be predicted by temporal coding. We conclude that temporal codes from the periphery can mediate discriminative taste processing.

Animals↗
PubMed2005

Lineage-specific loss of function of bitter taste receptor genes in humans and nonhuman primates.

Since the process of becoming dead genes or pseudogenes (pseudogenization) is irreversible and can occur rather rapidly under certain environmental circumstances, it is one plausible determinant for characterizing species specificity. To test this evolutionary hypothesis, we analyzed the tempo and mode of duplication and pseudogenization of bitter taste receptor (T2R) genes in humans as well as in 12 nonhuman primates. The results show that primates have accumulated more pseudogenes than mice after their separation from the common ancestor and that lineage-specific pseudogenization becomes more conspicuous in humans than in nonhuman primates. Although positive selection has operated on some amino acids in extracellular domains, functional constraints against T2R genes are more relaxed in primates than in mice and this trend has culminated in the rapid deterioration of the bitter-tasting capability in humans. Since T2R molecules play an important role in avoiding generally bitter toxic and harmful substances, substantial modification of the T2R gene repertoire is likely to reflect different responses to changes in the environment and to result from species-specific food preference during primate evolution.

Animals↗
PubMed2003

Inhibition of seed germination by extracts of bitter Hawkesbury watermelon containing cucurbitacin, a feeding stimulant for corn rootworm (Coleoptera: Chrysomelidae).

Cucurbitacins are feeding stimulants for corn rootworm used in baits to control the adults of this insect pest. Corn rootworm larvae also feed compulsively on cucurbitacins. Cucurbitacins are reported to be gibberellin antagonists that may preclude their use as seed treatments for these soil-dwelling insects. The crude extract of a bitter Hawkesbury watermelon containing cucurbitacin E-glycoside significantly inhibited germination of watermelon, squash, and tomato seeds. Although the germination of corn seed was not significantly inhibited, root elongation was inhibited by crude extracts, but not by high-performance liquid chromatography-purified cucurbitacin E-glycoside. Therefore, the effects of the major components in the bitter watermelon extract (e.g., sugars) on seed germination and root elongation were determined. Pure sugars (glucose and fructose), at concentrations found in watermelon extract, mimicked the inhibition of seed germination and root elongation seen with the crude bitter Hawkesbury watermelon extract. Removal of these sugars may be necessary to use this extract as a bait for corn rootworm larvae as a seed or root treatment.

Animals↗
PubMedDate not supplied

Preparation of microcapsules masking the bitter taste of enoxacin by using one continuous process technique of agglomeration and microencapsulation.

In order to mask the bitter taste of drugs, a novel microencapsulation process combined with the wet spherical agglomeration (WSA) technique was developed by using a modified phase separation method. The spherical agglomerates of enoxacin (ENX) with various additives including disintegrants were successfully produced in the system of acetone-n-hexane-ammonia water or acetone-n-hexane-distilled water by the WSA, using flocculation phenomena of particles in liquid. Resultant agglomerates could be microencapsulated continuously with Eudragit RS utilizing the phase separation method in the same system as agglomeration under stirring. 'Explosible' microcapsules which were free from the bitter taste could be produced in formulating finer particle size of ENX and 50 per cent of Primojel in core agglomerates, using distilled water as a bridging liquid, and treating with 20 per cent polymer coating level. These microcapsules were bioequivalent to the commercial ENX 100 mg tablets in beagle dogs. One continuous process technique of agglomeration and microencapsulation was useful for the design of ENX powders which masked the bitter taste and controlled the drug release rate.

Animals↗
PubMed1993

Perception of sweetness and bitterness in different vehicles.

In the present study, we investigated taste-taste, taste-vehicle, and simultaneous taste-vehicle-taste mixtures. Subjects made estimates of the sweetness and bitterness of 27 stimuli. Sucrose (292, 585, and 1170 mM), caffeine (13, 26, and 52 mM), and binary mixtures of low (292-13 mM), middle (585-26 mM), and high (1170-52 mM) levels of both components were dispersed in water, carboxymethylcellulose (CMC) 1% w/v, and gelatin 6% w/v. The sweetness and bitterness of the sucrose-vehicle-caffeine combinations were significantly weaker than the respective sucrose-vehicle and caffeine-vehicle combinations. The emerged mutual suppressive effects were asymmetrical and persisted when both tastants were presented in CMC and gelatin. Moreover, the increase in vehicle consistency and the simultaneous addition of another taste reduced the perceived intensity of a taste either presented alone or dissolved in water. For both sweetness and bitterness, the total taste suppression observed was always significant.

Adolescent↗
PubMed2006

Ischemic colitis associated with use of a bitter orange-containing dietary weight-loss supplement.

Since the US Food and Drug Administration banned the use of dietary supplements containing ephedra in February 2004, numerous "ephedra-free" weight-loss products have appeared on the market. Many of these supplements contain compounds such as bitter orange that are similar in structure and action to ephedra. We describe a patient in whom ischemic colitis developed 1 week after initiation of a bitter orange-containing weight-loss supplement. The patient had no other predisposing factors, and discontinuation of the supplement led to immediate improvement and ultimate resolution of her symptoms. Both consumers and health care professionals should be aware of the potential harm that bitter orange-containing dietary supplements can cause and report such adverse events to the US Food and Drug Administration.

Citrus↗
PubMed1999

Patch clamp recording of the responses to three bitter stimuli in mouse taste cells.

Although several pathways of bitter taste signal transduction have been proposed in taste cells, these mechanisms have not been elucidated in detail. To investigate the diversity of responses to bitter stimuli, we recorded the electrophysiological responses to quinine, denatonium and naringin using whole-cell patch clamp technique in isolated taste cells of C57BL/6J mice. Ten mM quinine induced depolarizing response under the current clamp mode, and inward current response under the voltage-clamp mode (holding potential -80 mV) using both K+ (with pseudo intracellular solution) and Cs+ (K+ was substituted by Cs+ in the pseudo intracellular solution) pipettes. However, when the K+ pipette was used, the membrane conductance was suppressed and activated in succession. On the other hand, the membrane conductance was only activated when the Cs+ pipette was used. Half to one mM denatonium induced depolarizing response under the current clamp mode, and outward current response under the voltage clamp mode with both pipettes. Using these pipettes, the membrane conductance was activated or suppressed in the individual case. Naringin-induced responses were not detected in these measurements. These electrophysiological recordings suggest that multiple transduction mechanisms are involved in bitter taste perception in mouse taste cells.

Animals↗
PubMed2001

A peripheral mechanism for behavioral adaptation to specific "bitter" taste stimuli in an insect.

Animals have evolved several chemosensory systems for detecting potentially dangerous foods in the environment. Activation of specific sensory cells within these chemosensory systems usually elicits an aversive behavioral response, leading to avoidance of the noxious foods. Although this aversive behavioral response can be adaptive, there are many instances in which it generates "false alarms," causing animals to reject harmless foods. To minimize the number of false alarms, animals have evolved a variety of physiological mechanisms for selectively adapting their aversive behavioral response to harmless noxious compounds. We examined the mechanisms underlying exposure-induced adaptation to specific "bitter" compounds in Manduca sexta caterpillars. M. sexta exhibits an aversive behavioral response to many plant-derived compounds that taste bitter to humans, including caffeine and aristolochic acid. This aversive behavioral response is mediated by three pairs of bitter-sensitive taste cells: one responds vigorously to aristolochic acid alone, and the other two respond vigorously to both caffeine and aristolochic acid. We found that 24 hr of exposure to a caffeinated diet desensitized all of the caffeine-responsive taste cells to caffeine but not to aristolochic acid. In addition, we found that dietary exposure to caffeine adapted the aversive behavioral response of the caterpillar to caffeine, but not to aristolochic acid. We propose that the adapted aversive response to caffeine was mediated directly by the desensitized taste cells and that the adapted aversive response did not generalize to aristolochic acid because the signaling pathway for this compound was insulated from that for caffeine.

Adaptation, Physiological↗
PubMed2005

Bitter and sweet/umami taste receptors with differently evolutionary pathways.

In this study,we investigated the evolutionary pathways of bitter, sweet and umami receptors using bioinformatic and phylogenetic analyses. Our results showed that the distantly evolutionary relationship between bitter and sweet/umami receptors. Our results also showed that bitter and sweet/umami receptors have differently evolutionary pathways,suggesting that the different evolutionary pathways may resulte in the differences of these three receptors in function.

Amino Acid Sequence↗
PubMed1991

[Simultaneous determination of five bitter secoiridoid glycosides in nine Chinese Gentiana species used as the Chinese drug "long dan" by high performance liquid chromatography].

A new and rapid analytical method for the simultaneous determination of five bitter secoiridoid glycosides (gentiopicroside, GTP; swertiamarin, SWT; sweroside, SWO; amarogentin, AMG; amaroswerin, AMS) in the Chinese drug "Long Dan", roots of Gentiana manshurica and 8 allied species by high performance liquid chromatography (HPLC) has been developed. The HPLC system consisting of an apparatus from Shimadzu (model LC-4A), with a UV-detector (SPD-2AS), a data processor (Chromatopac C-R2AX), a column oven (CTO-2AS), and a Zorbax ODS column (25 cm x 4.6 mm ID) was used. Using MeOH--H2O as the mobile phase, the linear concentration-program of methanol was [time (min):C (MeOH)]: [0:20]----[6:20]----[6.01:40]----[23:stop]. The temperature of column oven was 40 degrees C. The bitter secoiridoid glycosides eluted were detected at a wavelength of 254 nm and the analysis was successfully carried out within 23 minutes. This method is sensitive, rapid, accurate and has good reproducibility. Recoveries of each secoiridoid glycoside were 100.0-101.5% with coefficients of variation 0-2.5% (n = 3). The contents of five bitter secoiridoid glycosides in the roots of G. manshurica and eight allied species indigenous to China were determined and reported.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Neural responses of the glossopharyngeal nerve to several bitter stimuli in mice.

The neural reaction to bitter stimuli was tested in the glossopharyngeal (GL) and chorda tympani (CT) nerves of mice. Relative responses to several bitter stimuli (quinine, iso-alpha-acids, L-tryptophan and L-phenylalanine) were greater in the GL nerve than in the CT nerve. Strain variability for taste sensitivity to bitter stimuli existed between two strains (C57BL and BALB/C). The GL nerve response to caffeine, iso-alpha-acids and L-phenylalanine in the BALB/C strain was greater than the response in the C57BL strain.

Amino Acids↗
PubMed2004

A bitter melon extract inhibits the P-glycoprotein activity in intestinal Caco-2 cells: monoglyceride as an active compound.

P-glycoprotein (P-gp) is a 170 kDa membrane protein that belongs to the ATP-binding cassette (ABC) transporter superfamily. In normal tissues, P-gp functions as an ATP-dependent efflux pump that excretes highly hydrophobic xenobiotic compounds, playing an important role in protecting the cells/tissues from xenobiotics. In the present study, chemical substances that could directly modulate the intestinal P-gp activity were searched in vegetables and fruits. By using human intestinal epithelial Caco-2 cells as a model of the small intestinal cells, we observed that a bitter melon fraction extracted from 40% methanol showed the greatest increase of the rhodamine-123 accumulation by Caco-2 cells. Inhibitory compounds in the bitter melon fraction were then isolated by HPLC using Pegasil C4 and Pegasil ODS columns. The HPLC fraction having the highest activity was analyzed by (1)H-NMR and FAB-MS, and the active compound was identified as 1-monopalmitin. It is interesting that certain types of monoglyceride might be involved in the drug bioavailability by specifically inhibiting the efflux mediated by P-gp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

Early developmental change in bitter taste responses in human infants.

Human newborns (birth-6 days) and older infants (14-180 days) were allowed to ingest both urea (0.12-0.24 M) in a mildly sweet diluent and the diluent alone, and multiple measures of responsivity were obtained (relative intake, sucking behavior, and hedonic ratings based on facial expressions and body movements). For newborns, there was no indication of rejection of urea relative to the diluent in measures of intake or sucking behavior; rather, their responses were predominantly controlled by the order of presentation of the two tastes. In contrast, older infants tended to reject all concentrations of urea according to these measures. Hedonic ratings provided an indication of limited rejection of the bitter taste by newborns, but older infants were still found to respond more consistently. These data suggest there is an early developmental change in bitter taste perception.

Facial Expression↗