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The alcohol-deprivation effect in hybrid mice.

Hybrid mice (F1 CBA x C57Bl/6) after prolonged access to saccharin-menthol flavored 30% alcohol (FA) were deprived of it on two occasions, followed by test choices between (1) FA and water, and (2) FA and similarly flavored water. Although many mice failed to show deprivation-induced increases in FA intake, the mean rate of FA drinking during the first 1.5 h of renewed access was significantly increased even in the second test. Comparisons between the two tests suggest that flavor factors are generally less important than ethanol-seeking behavior.

Alcohol Drinking↗

Induction of group-1 and group-2 UDP-glucuronosyltransferase in microsomes from the livers of C57 Bl/6 mice.

In a study of multiple forms of liver microsomal UDPglucuronosyltransferase (EC 2.4.1.17) with different substrate specificities, enzyme induction was examined in inducible C57 Bl/6 mice pretreated with phenobarbital, 3-methylcholanthrene, Aroclor 1254, safrole, beta-naphthoflavone, and pregnenolone-16-alpha-carbonitrile. Phenobarbital and 3-methylcholanthrene were much more potent inducers than the other four compounds. 3-methylcholanthrene stimulated the glucuronidation of 4-nitrophenol, 4-bromophenol, and 4-chlorophenol ("group-1' substrates) more than phenobarbital, whereas phenobarbital stimulated the glucuronidation of 4-hydroxyphenobarbital, menthol, eugenol, 4-hydroxybiphenyl, morphine, 1-borneol, 4-hydroxyphenytoin, and 1,2,3,4-tetrahydro-1-naphthol ("group-2' substrates). This pattern is analogous to that previously observed in rat-liver microsomes.

Animals↗

Cigarette promotional offers: who takes advantage?

BACKGROUND: Promotional offers on cigarettes (e.g., dollar-off, multipack discounts) composed the largest share of tobacco industry marketing expenditures, totaling $8.9 billion, or 72% of the total budget in 2002. Internal industry documents indicate that young adults, potential quitters, and other price-sensitive groups are the targets of these marketing tactics. How effective they are in actually reaching these groups in the general population of smokers has not yet been investigated. METHODS: Data were from 4618 current smokers responding to the large, random-digit-dialed population-based 2002 California Tobacco Survey. The characteristics were identified of smokers who reported that they used these offers "every time I see one." RESULTS: Thirty-five percent of smokers used promotional offers every time they saw one. Multivariate analyses identified young adults, women, African Americans, those with higher daily cigarette consumption, and those worried about cigarette costs as more likely to use promotional offers at every opportunity. Smokers most committed to quitting were no more likely to use promotional offers than those with no intention to quit. Cigarette brand was highly correlated with age and race/ethnicity, and therefore was not included in the multivariate analysis. Those who smoked menthol cigarettes and Camels, more often young adults and African Americans, were much more likely than those of other brands to use promotional offers. CONCLUSIONS: With the exception of smokers intending to quit, cigarette promotional offers are effectively reaching most industry-targeted groups. Importantly, young adults, who have the greatest long-term customer potential, are responding.

Adolescent↗

Chiral recognition by fluorescent chemosensors based on N-dansyl-amino acid-modified cyclodextrins.

Four kinds of N-dansyl-amino acid-modified beta-cyclodextrins (beta-CDs) were prepared as fluorescent chemosensors for chiral discrimination. The use of an amino acid as a spacer improved binding affinities and chiral discrimination abilities of the chemosensors. N-dansyl-l-Phe-modified beta-CD showed high d-selectivity for norbornane derivatives and N-dansyl-d-Phe-modified beta-CD showed high l-selectivity for menthol. Microcalorimetric titration results indicate that the chemosensors selectively accommodate the enantiomer that induces the least unfavorable entropy change on making an inclusion complex.

Amino Acids↗

Natural terpenes: self-assembly and membrane partitioning.

Monoterpenes (MTs) are highly hydrophobic substances present in essential oils. They cover a wide spectrum of biological effects with a membrane interaction as a common point. Here we studied the surface activity of camphor, cineole, thymol, menthol and geraniol, and their ability to reach and incorporate into model membranes affecting some features of their dynamic organization. All the MTs studied self-aggregated in water with critical micellar concentrations (CMC) between 3 and 8 microM. Their octanol-water and membrane-water partition coefficients were correlated with one another. They all penetrated in monomolecular layers of dipalmitoyl-phosphatildylcholine at the air-water interface, even at surface pressures (pi) above the equilibrium lateral pressure of bilayers; thymol exhibited the highest (61.3 mN/m) and camphor the lowest (37 mN/m) pi(cut-off) value. They affected the self-aggregation of Triton X-100, increasing its CMC from 0.16 mM in the absence of MTs up to 0.68 mM (e.g. for geraniol), and the topology of sPC vesicles, increasing its surface curvature, suggesting their location at the polar head group region of the membrane. The latter was supported by their ability to increase differentially the polarity of the membrane environment sensed by two electrochromic dyes. Dipole moment values (between 1.224 and 2.523 D) and solvation areas (between 80 and 97 A(2)) were calculated from their energy-minimized structures. The relative contribution of each experimental, theoretical and structural property to determine MTs' effects on membrane dynamics were evaluated by a principal component analysis.

Air↗

The effect of pretreatment with terpenes on transdermal iontophoretic delivery of arginine vasopressin.

This study investigates the effects of terpenes and iontophoresis on the in vitro permeation of arginine vasopressin (AVP) through rat skin and the biophysical changes induced by the chemical enhancers in the stratum corneum (SC) lipids by FT-IR spectroscopy. Pretreatment with terpenes (e.g. 5% w/v, carvone, pulegone, cineole and menthol in EtOH:W (2:1) system) increased (P < 0.05) the flux of AVP in comparison to control (not pretreated with enhancer) but was not significantly different (P > 0.05) in comparison to iontophoresis. Amongst different terpenes studied maximum enhancement ratio was observed with cineole. In combination, iontophoresis did not further increase (P > 0.05) the permeation of AVP through the enhancer pretreated epidermis in comparison to pretreatment with enhancer or iontophoresis alone. Hence it was concluded that although the combination was effective in flux enhancement compared to control, there was no synergism in action between terpenes and iontophoresis. FT-IR spectroscopic studies revealed that EtOH:W (2:1) system is not effective in lipid extraction. The area under the symmetric and asymmetric stretching peaks at 2850 and 2920 cm(-1) revealed that at the concentration used terpenes did not extract any lipids from the epidermis. The mode of action of terpenes is attributed to the breaking of hydrogen bonds between the ceramide head groups of lipids in the SC leading to greater fluidization of the SC lipids.

Administration, Cutaneous↗

Effects of antimicrobial components of essential oils on growth of Bacillus cereus INRA L2104 in and the sensory qualities of carrot broth.

The possible use of antimicrobials from seven plant essential oils as food preservatives was studied by examining their effects on the growth kinetics of activated Bacillus cereus INRA L2104 spores inoculated into tyndallized carrot broth. The effects of various concentrations of borneol, carvacrol, cinnamaldehyde, eugenol, menthol, thymol, and vanillin were determined. Five microliters of cinnamaldehyde, 15 microl of carvacrol, or 30 mg of thymol per 100 ml of inoculated carrot broth completely inhibited bacterial growth for more than 60 days at 16 degrees C. Lower concentrations of the three antimicrobials prolonged the lag phase and reduced both the exponential growth rate and the final population densities of cultures. The study of the sensory characteristics of the supplemented broths suggested that low concentration of cinnamaldehyde enhanced the taste of carrot broth, and that it did not have any adverse effect on the taste and smell of carrot broth at concentrations less than 6 microl 100 ml(-1).

Anti-Bacterial Agents↗

Skin permeation of propranolol from polymeric film containing terpene enhancers for transdermal use.

To develop the suitable film formulations of propranolol hydrochloride (PPL) containing enhancers for transdermal use, polymeric film formulations were prepared by employing ethyl cellulose (EC) and polyvinyl pyrrolidone (PVP) as a film former, and dibutyl phthalate (DBP) as a plasticizer. Terpenes such as menthol and cineole, and propylene glycol (PG) were also employed as a chemical enhancer to improve the skin penetration of PPL. The film preparations were characterized in physical properties such as uniformity of drug content, thickness and moisture uptake capacity. Release and skin permeation kinetics of PPL from film preparations were examined in the in vitro studies using a Franz-type diffusion cell. The uniformity of drug content was evidenced by the low S.D. values for each film preparation. The moisture uptake capacity and drug release rate increased with the increase of PVP in each preparation. Enhancers examined in the present study also increased the moisture uptake capacity and release rate of PPL from the film preparations. Increasing the concentration of PPL from 1 to 2 mg/cm2 in the film enhanced the release rate of PPL, while no effect of enhancer concentrations on the release rate from the film preparations was observed. In vitro skin permeation study showed that cineole was the most promising enhancer among the enhancers examined in the present study and suggested that the suitable compositions of film preparation would be EC:PVP:PPL=6:3:4 with 10% (w/w) cineole and 7:2:4 with 10% (w/w) PG and cineole, which provided high skin permeation rates at 93.81+/-11.56 and 54.51+/-0.52 microg/cm2/h, respectively.

Administration, Cutaneous↗

Vortex-assisted liquid-liquid microextraction based on natural deep eutectic solvents for the determination of pyrethroid pesticides in urine.

A novel, facile, and environmentally friendly analytical method was developed based on vortex-assisted liquid-liquid microextraction and high-performance liquid chromatography with diode-array detection for detecting pyrethroid pesticides (PPs) in urine. Natural deep eutectic solvents (NADESs) were prepared using plant essential oil-derived monoterpenoids (thymol, carvacrol, and menthol) combined with aromatic primary alcohols (benzyl alcohol, phenethyl alcohol, and phenylpropyl alcohol) as hydrogen bond donors and acceptors. These solvents served as environmentally benign extraction media, thereby avoiding the use of conventional volatile, toxic organic solvents. NADESs are naturally derived, easy to prepare, biodegradable, and environmentally friendly solvents. Hydrophobic and &#x3c0;-&#x3c0; interactions between the NADESs and PPs may contribute to enhancing the affinity of PPs toward the NADESs phase. Vortex technology, accelerating mass transfer between the sample and extractant phases, enables fast extraction of PPs. Under optimized conditions, the method achieved a low detection limit (0.002&#xa0;mg&#xa0;L-1), satisfactory precision with relative standard deviations (0.3%-2.4%), and acceptable recovery (80.7%-86.2%). The method demonstrated excellent performance in urine analysis and was feasible as a facile and green strategy for monitoring the content of PPs in biological matrices and assessing exposure risk.

Liquid Phase Microextraction↗

Investigation of factors affecting the adsorption of functional molecules onto gel silicas. 1. Flow microcalorimetry and infrared spectroscopy.

Flow microcalorimetry and infrared spectroscopy were used to study the surface structure and adsorptive properties of a series of calcined and uncalcined porous silicas. The adsorbates DL-menthol, (R)-(+)-limonene, (+/-)-citronellal and carvone were selected for their functionality, that included carbonyl, vinylic and hydroxyl groups. The amounts of probe retained by the silicas together with the energy exchange involved in the adsorption/desorption process were determined by flow microcalorimetry. The functional groups involved in these interactions were studied by means of infrared spectroscopy. It was observed that the strongest interactions with the silica surface took place through hydrogen bonding onto the surface silanol. The most retentive probes were found to be those with a carbonyl group in their structure. Adsorption onto calcined silicas was found to be less energetic than onto the equivalent calcined samples. The adsorption densities were compared with theoretical predictions based on molecular models. In all cases apart from citronellal monolayer coverage were not observed due to steric effects.

Journal Article↗

A study of microemulsion systems for transdermal delivery of triptolide.

Triptolide possesses immunosuppressive, anti-fertility and anti-cancer activities. Due to its severe toxicity, microemulsions with controlled, sustained and prolonged delivery of triptolide via a transdermal route are expected to reduce its adverse side effects. The purpose of the present study was to investigate the microemulsions for transdermal delivery of triptolide. The pseudo-ternary phase diagrams were developed and various microemulsion formulations were prepared using oleic acid as an oil, Tween 80 as a surfactant and propylene glycol as a cosurfactant. The droplet size of microemulsions was characterized by photocorrelation spectroscopy. The transdermal ability of triptolide from microemulsions was evaluated in vitro using Franz diffusion cells fitted with mouse skins and triptolide was analyzed by high-performance liquid chromatography. The effect of menthol as a permeation enhancer, and the loading dose of triptolide in microemulsions on the permeation rate were also evaluated. The triptolide-loaded microemulsions showed an enhanced in vitro permeation through mouse skins compared to an aqueous solution of 20% propylene glycol containing 0.025% triptolide. The permeation of microemulsions accorded with the Fick's first diffusion law. No obvious skin irritation was observed for the studied microemulsion ME6, but the aqueous solution of 20% propylene glycol containing 0.025% triptolide revealed the significant skin irritation. The results indicate that the studied microemulsion systems, especially ME6, may be promising vehicles for the transdermal delivery of triptolide.

Administration, Cutaneous↗

Anti-Candida activity of Brazilian medicinal plants.

Essential oils and ethanolic extracts from the leaves and/or roots of 35 medicinal plants commonly used in Brazil were screened for anti-Candida albicans activity. The oils were obtained by water-distillation using a Clevenger-type system. Essential oils from 13 plants showed anti-Candida activity, including Aloysia triphylla, Anthemis nobilis, Cymbopogon martini, Cymbopogon winterianus, Cyperus articulatus, Cyperus rotundus, Lippia alba, Mentha arvensis, Mikania glomerata, Mentha piperita, Mentha sp., Stachys byzantina, and Solidago chilensis. The ethanol extract was not effective at any of the concentrations tested. Chemical analyses showed the presence of compounds with known antimicrobial activity, including 1,8-cineole, geranial, germacrene-D, limonene, linalool, and menthol.

Antifungal Agents↗

Resolution enhancement in spectra of natural products dissolved in weakly orienting media with the help of 1H homonuclear dipolar decoupling during acquisition: application to 1H-13C dipolar couplings measurements.

In weakly orienting media such as poly-gamma-benzyl-L-glutamate (PBLG) a polymer that forms a chiral liquid crystal in organic solvents, the spectral resolution for embedded molecules is usually poor because of numerous (1)H, (1)H dipolar couplings that generally broaden proton spectra. Therefore (1)H, (13)C dipolar couplings are difficult or impossible to measure. Here, we incorporate Flip-Flop decoupling during detection into an HSQC experiment. Flip-Flop removes the (1)H, (1)H dipolar couplings and scales the chemical shifts of the protons as well as the (1)H, (13)C dipolar couplings during detection. A resolution gain by a factor 1.5-4.2 and improved signal intensity by an average factor of 1.6-1.7 have been obtained. This technique is demonstrated on (+)-menthol dissolved in a PBLG/CDCl(3) phase.

Anisotropy↗

Herbal monoterpene alcohols inhibit propofol metabolism and prolong anesthesia time.

2,6-Diisopropylphenol (Propofol) is a short-acting intravenous anesthetic that is rapidly metabolized by glucuronidation and ring hydroxylation catalyzed by cytochrome P450. The goal of this research was to determine whether dietary monoterpene alcohols (MAs) could be used to prolong the anesthetic effect of propofol by inhibiting propofol metabolism in animals. Mice were injected intraperitoneally (i.p.) with MAs (100-200) mg/kg followed by the administration of 100 mg/kg propofol 40 min later via an i.p. injection. The time of the anesthesia of each mouse was recorded. It was found that (+/-)-borneol, (-)-carveol, trans-sobrerol, and menthol significantly extended the anesthetic effect of propofol (>3 times). The concentration of propofol in the mouse blood over time (up to 180 min) also increased in mice pre-treated with (-)-borneol, (-)-carveol, and trans-sobrerol. The volume of distribution of propofol decreased in the (-)-borneol (p<0.05), pre-treated group as compared to the propofol control group. Moreover, the maximum blood concentration of propofol and the concentration of propofol in the blood as indicated by the area under the curve were significantly increased in (-)-borneol and (-)-carveol pre-treated groups. Additional evidence using rat hepatocytes showed that (-)-borneol inhibited propofol glucuronidation whereas trans-sobrerol and (-)-carveol inhibited cytochrome P450 dependent microsomal aminopyrine N-demethylation. These results suggest that (-)-borneol extends propofol-induced anesthesia by inhibiting its glucuronidation in the mouse whereas trans-sobrerol (-)-carveol extends propofol-induced anesthesia by inhibiting P450 catalyzed propofol metabolism.

Alcohols↗

Novel aspects of signaling and ion-homeostasis regulation in immunocytes. The TRPM ion channels and their potential role in modulating the immune response.

In just a few years, the discovery and subsequent characterization of several members of the TRPM family of cation channels have provided us with surprising new insights into unknown aspects of cellular ion-homeostasis regulation. This includes reports about ADP-ribose functioning as a novel intracellular second messenger and gating molecule of the Ca(2+)-permeable TRPM2 channel, studies demonstrating the central role of mouse TRPM5 in taste signaling, as well as the unexpected involvement of TRPM6 and TRPM7 in regulating Mg(2+)-homeostasis, or the cool properties of TRPM8 acting as a cold and menthol sensor in sensory neurons. At least four of the eight known TRPM proteins have been shown to be present in the immune context: TRPM1 (melastatin), TRPM2, TRPM4 and TRPM7. Although we currently lack animal models allowing a detailed assessment of the potential involvement of TRPM family members in modulating the immune response, the powerful combination of molecular and cellular biology, biochemistry, and electrophysiology have provided the first clues as to how these molecules could contribute to immunity.

Animals↗

Noxious heat receptors present in cold-sensory cells in rats.

Noxious heat above approximately 45 degrees C applied on cold spots evokes a paradoxical cold sensation by activating cold fibers. It remains unresolved whether cold receptors respond to heat as well, or whether noxious-heat receptors and cold receptors coexist in the same fiber. Recently, noxious heat receptors (TRPV1) and cold receptors (TRPM8) have been cloned. It is controversial, however, whether TRPV1 and TRPM8 coexist in the same sensory neuron. Here, we investigate colocalization of these receptors in dorsal root ganglion (DRG) of rats. TRPV1 was expressed in 29% of TRPM8-positive cells in DRG sections. In Ca2+ imaging, noxious heat excited many of the cold-sensitive cells in culture. In a whole-cell current-clamp mode, noxious heat, capsaicin, cooling and menthol all evoked receptor potentials and impulses in a subset of DRG neurons. This colocalization of TRPV1 and TRPM8 in a DRG neuron may be the basis for the paradoxical cold sensation.

Animals↗

Coiled coils direct assembly of a cold-activated TRP channel.

Transient receptor potential (TRP) channels mediate numerous sensory transduction processes and are thought to function as tetramers. TRP channel physiology is well studied; however, comparatively little is understood regarding TRP channel assembly. Here, we identify an autonomously folded assembly domain from the cold- and menthol-gated channel TRPM8. We show that the TRPM8 cytoplasmic C-terminal domain contains a coiled coil that is necessary for channel assembly and sufficient for tetramer formation. Cell biological experiments indicate that coiled-coil formation is required for proper channel maturation and trafficking and that the coiled-coil domain alone can act as a dominant-negative inhibitor of functional channel expression. Our data define an authentic TRP modular assembly domain, establish a clear role for coiled coils in ion channel assembly, demonstrate that coiled-coil assembly domains are a general feature of TRPM channels, and delineate a new tool that should be of general use in dissecting TRPM channel function.

Amino Acid Sequence↗

Allosteric positive interaction of thymol with the GABAA receptor in primary cultures of mouse cortical neurons.

Thymol is a naturally occurring phenolic monoterpene known for its anti-microbial and anti-oxidant properties. It is used in dental practice and in anaesthetic halothane preparations. Recent studies have reported enhanced GABA(A) receptor-operated chloride channel activity and increased binding affinity of [(3)H]flunitrazepam in the presence of thymol. In the present work, we more closely examined the pharmacological action of thymol on the native GABA(A) receptor by using primary cultures of cortical neurons. Thymol enhanced GABA-induced (5 microM) chloride influx at concentrations lower than those exhibiting direct activity in the absence of GABA (EC(50) = 12 microM and 135 microM, respectively). This direct effect was inhibited by competitive and non-competitive GABA(A) receptor antagonists. Thymol increased [(3)H]flunitrazepam binding (EC(50) = 131 microM) and showed a tendency to increase [(3)H]muscimol binding. These results confirm that thymol is a positive allosteric modulator of the GABA(A) receptor. The thymol structural analogues menthol and cymene, which lack an aromatic ring or a hydroxyl group, did not affect [(3)H]flunitrazepam binding. Using a pharmacophoric model that includes a hydrogen bond donor group as well as an aromatic ring with two aliphatic substituents, we propose to demonstrate the molecular essential features of these compounds to interact with GABA(A) receptors. Thymol (0-1 mM) did not affect cellular viability.

Anesthetics, Intravenous↗