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PubMed1994

Growth inhibition of rat liver epithelial tumor cells by monoterpenes does not involve Ras plasma membrane association.

The role of altered ras oncoprotein (Ras) farnesylation and membrane association in the growth inhibitory effects of several monoterpenes (limonene, perillic acid, perillyl alcohol, menthol, pinene and cineole) was investigated in rat liver epithelial cells. All of the above compounds except cineole inhibited the growth of viral Ha-ras-transformed rat liver epithelial cells (WB-ras cells) at concentrations of 0.25-2.5 mM. These cells, however, were not necessarily more sensitive to these compounds compared to non-transformed and viral raf-transformed rat liver epithelial cells. Growth inhibition by limonene, perillic acid and pinene was only partially restored (20-50%) by supplementing the culture medium with 2 mM mevalonic acid. Western blot analyses of cytosolic and membranous fractions of WB-ras cells treated with monoterpenes indicated no change in Ras distribution. In contrast, lovastatin, a potent inhibitor of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase and Ras farnesylation, specifically reduced WB-ras cell growth and increased cytosolic levels of Ras. Thus, monoterpene-induced growth inhibition of rat liver epithelial cells was dissimilar to lovastatin and did not appear to involve altered Ras plasma membrane association.

Animals↗

PubMed2001

The influence of essential oils on human attention. I: alertness.

Scientific research on the effects of essential oils on human behavior lags behind the promises made by popular aromatherapy. Nearly all aspects of human behavior are closely linked to processes of attention, the basic level being that of alertness, which ranges from sleep to wakefulness. In our study we measured the influence of essential oils and components of essential oils [peppermint, jasmine, ylang-ylang, 1,8-cineole (in two different dosages) and menthol] on this core attentional function, which can be experimentally defined as speed of information processing. Substances were administered by inhalation; levels of alertness were assessed by measuring motor and reaction times in a reaction time paradigm. The performances of the six experimental groups receiving substances (n = 20 in four groups, n = 30 in two groups) were compared with those of corresponding control groups receiving water. Between-group analysis, i.e. comparisons between experimental groups and their respective control groups, mainly did not reach statistical significance. However, within-group analysis showed complex correlations between subjective evaluations of substances and objective performance, indicating that effects of essentials oils or their components on basic forms of attentional behavior are mainly psychological.

Aromatherapy↗

PubMed2001

Perception of trigeminal chemosensory qualities in the elderly.

One hundred healthy elderly subjects (65-88 years) were tested for their ability to: (i) assign verbal labels from a list of trigeminal type descriptors to six odorants known to have a strong trigeminal component; (ii) discriminate between intensity-matched pairs of these odorants in an odd-ball paradigm. Their performance was compared with that of 100 young controls (23--36 years). Young controls judged menthol and cineole as distinctly cool and fresh, acetic cid as pungent and sour and acetone as pungent, but showed no clear descriptive profile for ethanol and propanol. The descriptive profiles given by the elderly subjects correlated significantly with those given by the young controls for all six odorants and thus indicate a high degree of conformity in trigeminal perception of chemosensory qualities between the two age groups. In the odd-ball test the young controls correctly discriminated an average of 8.0 of 9 stimulus pairs presented, with most mistakes occurring in response to pairs with a similar trigeminal profile. With an average of 6.4 of 9 items correct, the discrimination performance of the elderly subjects was significantly poorer than that of the young controls but nevertheless significantly above chance at the group level with all 9 stimulus pairs. These results suggest that the nasal trigeminal system may experience some degree of age-related impairment but still contributes considerably to the perception and discrimination of chemosensory qualities in the elderly.

1-Propanol↗

PubMed1994

Insecticidal properties of several monoterpenoids to the house fly (Diptera: Muscidae), red flour beetle (Coleoptera: Tenebrionidae), and southern corn rootworm (Coleoptera: Chrysomelidae).

House flies, Musca domestica (L.), and their eggs were treated with 22 monoterpenoids to determine the topical, fumigant, and ovicidal activity of each compound. Fumigant activity of 14 monoterpenoids were examined further using red flour beetles, Tribolium castaneum (Herbst). Third-instar southern corn rootworm, Diabrotica undecimpunctata howardi Barber, were treated with carvacrol, citral, citronellal, menthol, pulegone, verbenol, and verbenone to determine their activity on larvae. Structure-activity relationships were evaluated with the toxicity data. We made comparisons between monocyclic aromatic, acyclic aliphatic, monocyclic aliphatic, and bicyclic aliphatic alcohols, ketones, aldehydes, and acids to determine toxicity differences involving the skeletal structure, amount of saturation, and associated functional groups of monoterapenoids. Ketones were more effective than alcohols in the topical, fumigant (T. castaneum), and ovicidal bioassays and less toxic than an analogous aldehyde in the topical, fumigant (M. domestica), and ovicidal bioassays. Aldehydes were more toxic than alcohols in the topical and fumigant (M. domestica) bioassays. In the topical and ovicidal bioassays, aromatic or acyclic alcohols, or both, were more effective than monocyclic and bicyclic alcohols. Vapors of bicyclic ketones were more toxic than monocyclic ketones to adult M. domestica. Monoterpenoid alcohols containing three carbon-carbon double bonds were more effective than saturated alcohols in the topical and larval bioassays. A mono-unsaturated ketone was more toxic than a structurally similar saturated ketone and two di-unsaturated ketones when it was applied topically to adult M. domestica. A saturated monocyclic ketone inhibited egg hatch more effectively than unsaturated monocyclic ketones.

Acyclic Monoterpenes↗

PubMed2000

Genetic polymorphism of UDP-glucuronosyltransferase 2B7 (UGT2B7) at amino acid 268: ethnic diversity of alleles and potential clinical significance.

UGT2B7 catalyses the glucuronidation of a diverse range of drugs, environmental chemicals and endogenous compounds. Hence, coding region polymorphisms of UGT2B7 are potentially of pharmacological, toxicological and physiological significance. Two variant UGT2B7 cDNAs encoding enzymes with either His or Tyr at residue 268 have been isolated. The variants, referred to as UGT2B7*1 and UGT2B7*2, respectively, arise from a C to T transversion at nucleotide 802 of the UGT2B7 coding region. Analysis of genomic DNA from 91 unrelated Caucasians and 84 unrelated Japanese demonstrated the presence of the variant alleles encoding UGT2B7*1 and UGT2B7*2 in both populations. However, while there was an approximately equal distribution of subjects homozygous for each allele in the Caucasian population, subjects homozygous for the UGT2B7*1 allele were over 10-fold more prevalent than UGT2B7*2 homozygotes in Japanese. The frequencies of the UGT2B7*1 and UGT2B7*2 alleles were 0.511 and 0.489, respectively, in Caucasians, and 0.732 and 0.268, respectively, in Japanese. The 95% confidence intervals for the two alleles did not overlap between Caucasians and Japanese. Rates of microsomal androsterone, menthol and morphine (3-position) glucuronidation were determined for genotyped livers from Caucasian donors. Statistically significant inter-genotypic differences were not apparent for any of the three substrates. Although the UGT2B7 polymorphism characterized here is probably not associated with altered enzyme activity, the results highlight the need to consider ethnic variability in assessing the consequences of UGT polymorphisms.

Adolescent↗

PubMed2000

Developmental regulation of monoterpene biosynthesis in the glandular trichomes of peppermint.

Monoterpene production in peppermint (Mentha x piperita L.) glandular trichomes is determined by the rate of biosynthesis, as determined by (14)CO(2) incorporation, and is restricted to leaves 12 to 20 d of age. Using oil glands isolated from peppermint leaves of different ages, in vitro assay of the eight sequential enzymes responsible for the biosynthesis of the principal monoterpene (-)-menthol indicated that all but one biosynthetic enzyme had a very similar developmental profile. Activities were highest in leaves 12 to 20 d of age, with a sharp peak centered at 15 d. The exception, (-)-menthone reductase, the last enzyme of the pathway, exhibited a later peak of activity, which was centered at approximately 21 d. The correlation between in vitro enzyme activity and the rate of biosynthesis measured in vivo suggests that monoterpene formation is controlled mainly by the coordinately regulated activity of the relevant biosynthetic enzymes. Developmental immunoblotting of limonene synthase, which catalyzes the committed step of the pathway, demonstrated a direct correlation between enzyme activity and enzyme protein, suggesting that the dynamic time course for the remaining pathway enzyme activities also reflects the corresponding protein levels. RNA-blot analyses indicated that the genes encoding enzymes of the early pathway steps are transcriptionally activated in a coordinated fashion, with a time course superimpossible with activity measurements and immunoblot data. These results demonstrating coincidental temporal changes in enzyme activities, enzyme protein level, and steady-state transcript abundances indicate that most of the monoterpene biosynthetic enzymes in peppermint are developmentally regulated at the level of gene expression.

Blotting, Northern↗

PubMed1987

The effect of aromatics on inspiratory and expiratory nasal resistance to airflow.

Unilateral inspiratory and expiratory nasal resistance to airflow were measured in 35 subjects using active anterior rhinomanometry. No significant difference was found between inspiratory and expiratory resistance. Inhalation of a mixture of aromatics, camphor, menthol, oil of pine needles and methyl salicylate had no effect on inspiratory or expiratory nasal resistance. Factors influencing inspiratory and expiratory resistance and the actions of aromatics are discussed.

Adult↗

PubMed2005

One pot conjugation of the polypeptides directed by phosphorus oxychloride.

A series of homopeptides and their conjugates were synthesized in one pot reaction in the presence of phosphorus oxychloride and the conjugate yield was structurally dependent. Menthol and benzylamine conjugated to the homopeptides quantitatively. Homopeptides when treated with diisopropyloxyphosphite (DIPPH) and NaClO yield the corresponding N-phosphoryl peptides. Electrospray ionization-mass spectrometry (ESI-MS)/MS was used to study the structure of peptide conjugates. This paper reports a simple method to synthesize the homopeptides and their conjugate derivatives and the fact that phosphoryl peptides could also be obtained by one pot reaction.

Benzylamines↗

PubMed2006

A novel type of cold-sensitive neuron in rat dorsal root ganglia with rapid adaptation to cooling stimuli.

Cold sensing in mammals is heterogeneous and more than one type of receptor molecule is likely to be involved in the transduction process. Most features of innocuous cold receptors have been explained by TRPM8, the cold and menthol receptor, but their fast adaptation to cooling has not yet been reproduced in cellular systems. In this study we have used a newly developed system for applying fast thermal stimuli to dissociated dorsal root ganglia (DRG) neurons from young rats (150-200 g) in primary culture. We describe a novel type of cold-sensitive rat DRG neuron with rapid adaptation to cooling. These cells (4.3% of the total DRG population) do not express either TRPM8 or the other cold-activated TRP channel, TRPA1, and the epithelial sodium channel (ENaC) is not involved in their transduction. Increases in intracellular calcium induced by cooling in rapidly adapting neurons are caused by calcium entry. These neurons express a large and rapidly adapting cold-induced inward current with a time constant of adaptation in the seconds range, and may correspond to the rapidly adapting cold receptors described in vivo.

Adaptation, Physiological↗

PubMed1998

The C fibre reflex of the cat urinary bladder.

1. Reflexes evoked in bladder parasympathetic neurones by electrical stimulation of bladder C afferent fibres were studied in cats anaesthetized with alpha-chloralose. The responses were compared with the ordinary micturition reflex evoked by low-threshold Adelta afferents from bladder mechanoreceptors and mediated by a spino-ponto-spinal reflex pathway. 2. The bladder was catheterized for fluid instillations and pressure recordings. Efferent reflex discharges were recorded from the cut central end of a small distal bladder branch of the pelvic nerve. The remaining bladder pelvic nerve branches were stimulated electrically close to the bladder. 3. Stimulation at C afferent intensity evoked a late reflex discharge in bladder pelvic efferents in all animals. The response was centrally mediated, had a latency of 150-250 ms, and was much weaker after stimulation on the contralateral nerve. 4. The bladder C fibre reflex differed in several functional aspects from the ordinary Adelta micturition reflex. It could be evoked at a low rate of stimulation, with an empty bladder and no background activity from bladder mechanoreceptors. In this situation, the normal Adelta micturition reflex is not elicited. The C fibre reflex also survived an acute spinalization at a low thoracic level. 5. The C fibre reflex was strongly inhibited by dorsal clitoris or dorsal penis nerve stimulation, an effect that was maintained after spinalization. It was facilitated by bladder or urethra exposure to cold and menthol, stimuli that activate specific cold-sensitive receptors associated with unmyelinated C afferents. 6. It is concluded that the central pathway of the C fibre reflex is spinal and partly separate from that of the ordinary micturition reflex. These observations are in keeping with the clinical finding that a bladder cooling reflex can be elicited in patients with disturbed descending control of the bladder.

Animals↗

PubMed2001

Sensory experiences in humans and single-unit activity in cats evoked by polymodal stimulation of the cornea.

1. The cornea of human subjects and of anaesthetised cats was stimulated with a jet of air of controlled flow, temperature and CO(2) concentration delivered by a gas aesthesiometer. 2. In humans, the intensity and magnitude of various components of the sensory experience (intensity of the sensation, degree of irritation, magnitude of burning and stinging pain, magnitude of the cold and warm components of the sensation) were measured using separate visual analog scales. In anaesthetised cats, the impulse response to the same stimuli was recorded from single mechanosensory, polymodal and cold-sensitive corneal fibres in the ciliary nerves. 3. Intensity-response curves for mechanical stimulation showed that all parameters of the sensation experienced by humans increased with the intensity of the stimulus. Mechanical stimuli recruited mainly phasic mechanosensory and polymodal afferents in the cat. 4. Acidic stimulation with gas mixtures of increasing CO(2) concentration evoked irritation, burning and to a lesser extent stinging pain of a magnitude roughly proportional to the intensity of the stimulus in humans. CO(2) primarily recruited polymodal afferents and weakly excited cold-sensitive fibres in the cat's cornea. 5. Heat stimuli evoked in humans a sensation profile similar to CO(2) but accompanied by a warmth component. In the cat's cornea, heat excited only polymodal fibres and silenced cold-sensitive corneal units. 6. Cold stimuli applied to the human cornea elicited a sensation of cooling that became irritant at the lowest temperatures. Corneal cold-sensitive fibres of the cat were activated in a manner proportional to the temperature drop, while polymodal nociceptor fibres were recruited only by the lowest temperatures. Topical menthol (0.2 mM) applied to humans evoked and later eliminated cold sensations produced by cold stimuli while the irritation sensation caused by low temperature stimuli still persisted. 7. Human subjects were able to identify masked mechanical, thermal and chemical stimuli applied to the cornea. 8. Irritation and cold sensations can therefore be evoked separately from the cornea by selective activation of mechanosensory, polymodal and cold corneal sensory afferents. Stimulation with different forms of energy usually leads to combined activation and/or inhibition of the different populations of sensory afferent fibres, evoking blended sensations that include irritation and thermal components in a variable degree.

Acids↗

PubMed1980

Evaluation of surfactant-like effects of commonly used remedies for colds.

Volatile aromatics, eucalyptol, eucalyptus oil, camphor and menthol were spread on synthetic DPL films and pulmonary surfactants; the initial surface pressure of the surfactants was measured and the additional surface pressure increment recorded. Eucalyptol was allowed to be inhaled by rabbits and lung compliance was monitored. Under our experimental conditions the volatile aromatics exhibited surfactant-like effects, namely a decrease in surface tension between water and air and thus improved lung compliance values in vivo.

Animals↗

PubMedDate not supplied

Fatal large-volume mouthwash ingestion in an adult: a review and the possible role of phenolic compound toxicity.

OBJECTIVE: To describe a case of fatal mouthwash ingestion and review possible sources of toxicity. DESIGN: Case report. SETTING: Veterans Administration Medical Center. PATIENT: Single patient with massive mouthwash ingestion. MAIN RESULTS: This patient was a 45-year-old man who developed cardiovascular collapse and multiorgan system failure following a massive ingestion of mouthwash (almost 3 liters). His presentation was remarkable for a profound anion-gap metabolic acidosis and a significant osmolar gap. No other co-ingestants were identified, and he expired despite full supportive care including dialysis and mechanical ventilation. An autopsy failed to identify any other cause of death. Nonalcoholic ingredients of this mouthwash are phenolic compounds (eucalyptol, menthol, and thymol), and large-volume mouthwash ingestion will produce exposure in the reported toxic range of these ingredients. CONCLUSIONS: When ingested in large quantities, the phenolic compounds in mouthwash may contribute to a severe anion-gap metabolic acidosis and osmolar gap, multiorgan system failure, and death. These compounds, in addition to alcohol, may account for the adverse effects associated with massive mouthwash ingestion.

Acidosis↗

PubMed2000

Preparation of griseofulvin for topical application using N-methyl-2-pyrrolidone.

We attempted to prepare a new griseofulvin formulation for topical application using N-methyl-2-pyrrolidone (NMP). Griseofulvin dissolves poorly in both water and oil, but dissolves in NMP to a concentration of about 100 mg/ml. A soybean oil-water emulsion with soybean lecithin and NMP as emulsifier and co-solvent, respectively, was prepared using a Microfluidizer, a high-pressure homogenizer. The size of the droplets in emulsion was about 200 nm, and the emulsion was stable for over 3 months. The skin permeation of griseofulvin through Yucatan micropig skin was studied in vitro using vertical type cells under donor phase open conditions. The permeation of griseofulvin from the NMP-water mixture (0-40%) into the skin tended to increase with increasing NMP concentration, although this finding was not statistically significant. Permeation from emulsion (oil phase, 20%; NMP 10-40%) was significantly higher than that from the water-NMP mixture. Permeation from the oil-NMP mixture was highest among the formulations investigated, and permeation from emulsion under donor phase closed conditions was significantly lower than that under open conditions. We believe that the evaporation of water from the emulsion after application to the skin was an important factor in skin permeation enhancement. When the emulsion containing 3% l-menthol was applied, a sufficient skin concentration (47 microg/cm3 in dermis) was obtained.

Administration, Topical↗

PubMedDate not supplied

GC profiles of volatile constituents from human urine obtained by closed loop stripping, purge and trap technique and simultaneous stem distillation-extraction.

Different techniques like "closed loop stripping" [CLSA], "purge and trap" [PTI], and continuous steam distillation extraction [SDE] were used to establish GC profiles of major histocompatibility complex-associated volatile constituents of human urine and statistically evaluated for reliability. Of the three methods investigated, PTI appeared to be superior for the detection of very volatile substances, whereas SDE was the most efficient one with respect to yield. A number of short to medium-chain ketones, 4-hydroxy-3-methoxy-styrene, menthol and nicotine were identified in preliminary analyses.

Chromatography, Gas↗

PubMed2002

Repellent activities of stereoisomers of p-menthane-3,8-diols against Anopheles gambiae (Diptera: Culicidae).

Four stereoisomers of p-menthane-3,8-diol, which make up the natural product obtained from Eucalyptus citriodora, were synthesized through stereoselective procedures. Repellency assays showed that all the four were equally active against Anopheles gambiae s.s. Racemic blends and the diastereoisomeric mixture of all the four isomers were also equally repellent. 1-alpha-terpeneol, with a single hydroxyl function at C-8 and unsaturation at C-8, and menthol, with a single hydroxyl function at C-3, were not repellent. The practical implication of these results is discussed.

Animals↗

PubMedDate not supplied

[Acute poisoning of an infant by cutaneous application of a local counterirritant and pulmonary antiseptic salve].

The case of acute poisoning reported here raises the question of the harmlessness of preparations destined for cutaneous application in infants. After describing the method perfected for the identification and estimation of camphor, menthol and thymol in biological material, the authors present the toxicological, clinical and biological arguments in favour of the notion that the cutaneous resorption of these substances was responsible for this acute intoxication in an infant. Particular attention should be paid to poisoning which may result, in the newborn and infant, from the cutaneous application of active substances.

Administration, Topical↗

PubMed1975

A further approach to quantitative determinations by thin layer chromatography.

In the proposed method, an internal standard, suitably chosen, is added in equal quantities to the sample was well as to the standard solutions. A standard curve is obtained by plotting the ratio Ds/Di for each of the standard solutions against the logarithm of the quantity of material present in each solution, where Ds and Di are the average diameters of the standard and internal standard spots, respectively. It was disclosed that the ratio Ds/Di for a given solution is constant, regardless of the volume of the solution spotted. As a result, no exact equal known volumes are needed for spotting. The method has been tested with estimation of menthol in volatile oil of peppermint and strychine in nux vomica seed.

Chemical Phenomena↗