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At least 19 recordsLinked to original sources
PubMed1992

The sensory effects of l-menthol on human skin.

Psychophysical measurements were made of the sensory effects of l-menthol applied topically to the forearm under controlled thermal conditions. In the first experiment, subjects judged the intensity and quality of sensations produced by warming or cooling the skin in the presence of menthol or the vehicle. During cooling, menthol intensified cutaneous sensations and increased reports of burning. During warming, menthol intensified sensations transiently at low temperatures and weakened them lastingly at higher temperatures; the frequency of reports of burning varied with intensity. A second experiment tested the hypothesis that menthol would lower the threshold for warmth and raise the threshold for heat pain. No change in either threshold was observed. The primary sensory effects of l-menthol on hairy skin are therefore to heighten the perception of cooling and to attenuate the perception of moderate warming. In contrast with other common chemical irritants, menthol's pungent qualities appear to be enhanced by cooling and suppressed by warming; this suggests that its sensory irritancy may be attributable to the stimulation of a population of high-threshold cold fibers or cold-sensitive nociceptors.

Adult↗
PubMed2025

Structural Basis of Cold and Menthol Sensing by TRPM8.

The transient receptor potential melastatin member 8 (TRPM8) is a polymodal ion channel that senses cold and menthol in mammals. Despite prior structural studies, the mechanisms by which cold and menthol activate TRPM8 remain unresolved. Here, we present cryo-EM structures representing the cold and menthol-dependent activation trajectories, combined with extensive functional analyses. We captured snapshots of cooling-dependent pore opening, which involves dramatic pore rearrangement, suggesting a mechanism for cold sensing. Moreover, menthol binds dynamically to induce channel activation, which may underlie menthol specificity for TRPM8. Finally, we show how TRPM8 integrates multiple modalities (cold and menthol) through overlapping but non-identical pathways, revealing the temperature-specific "cold spot". These findings enhance our understanding of the molecular basis of physically and chemically induced cool sensation in mammals.

Journal Article↗
PubMed1992

Menthol in the upper airway depresses ventilation in newborn dogs.

Upper airway cooling depresses ventilation in the newborn dog. Since airway cooling stimulates laryngeal cold receptors and inhibits laryngeal mechanoreceptors, the type of afferent ending responsible for this reflex cannot be easily identified. l-menthol, a specific stimulant of cold receptors in the absence of any cooling, has been used to ascertain the discrete role of upper airway cold receptors in this ventilatory depression. Experiments were carried out in 8 anesthetized 7-14-day-old dogs breathing through a tracheostomy with the upper airway functionally isolated. Constant flows of warm air (37 degrees C), with and without addition of l-menthol, and cold air (25 degrees C) were delivered through the upper airway in the expiratory direction. As compared to warm air trials, cold air and warm air + l-menthol trials greatly reduced ventilation (57.5 +/- 10.7% and 52.8 +/- 11.7% of control, respectively; P less than 0.01) mostly due to a prolongation of Te (291.2 +/- 106.4% and 339.2 +/- 90.0%, respectively, P less than 0.01). Section of the superior laryngeal nerve abolished the response to cold air. However, a residual depressive effect of l-menthol was still present in 3 of 5 animals and was abolished by nasal anesthesia, suggesting the involvement of nasal cold receptors. The results suggest that in the newborn dog stimulation of laryngeal cold receptors, without any concurrent inhibition of laryngeal mechanoreceptors, is a sufficient stimulus to cause respiratory depression.

Animals↗
PubMed1990

Immobilization of lipase from Candida cylindraceae and its use in the synthesis of menthol esters by transesterification.

Lipase (EC 3.1.1.3) from Candida cylindraceae has been immobilized by the cellulose-titanium chloride method, and on EP-400 polyethylene, with and without glutaraldehyde crosslinking, to give active preparations when assessed by their ability to catalyse the hydrolysis of tributyrin. In both cases, the use of glutaraldehyde crosslinking was shown to improve the stability of the preparations for repeated use. The lipase immobilized on EP-400 polyethylene was found to be effective in transesterification using tributyrin or triacetin as acyl donors with l-menthol as acceptor. The production of methyl butanoate and of methyl acetate using this immobilized preparation was in each case enhanced in the presence of Amberlite IR 47 Anion exchange resin (OH form).

Candida↗
PubMed1992

In vitro activity of taurolidine, chlorophenol-camphor-menthol and chlorhexidine against oral pathogenic microorganisms.

The antimicrobial activity of taurolidine (Taurolin, CAS 19388-87-5), a synthetic broad-spectrum antimicrobial agent and anti-toxin, and two conventional antiseptics, chlorophenol-camphor-menthol (CCM) and chlorhexidine digluconate (CHX) were compared using the serial dilution test on 10 potential oral pathogenic bacterial species. The minimum inhibitory and minimum bactericidal concentrations were lowest for CHX (MIC 0.03-0.12 mg/ml), followed by taurolidine (MIC 0.12-0.5 mg/ml) and CCM (MIC 0.5-2.0 mg/ml). However, if both bacterial efficacy and cytotoxicity are considered, only taurolidine achieves extensive bactericidal activity with tissue tolerability.

Anti-Infective Agents, Local↗
PubMed1990

Two-phase system membrane reactor with cofactor recycling.

For the purpose of constructing a two-phase system reactor the enzymatic process of l-menthol production with cofactor recycling was studied as a model. The half-life of the menthone reductase immobilized onto activated carbon was 4 times as high as that of the free enzyme. The enzyme was capable of regenerating NADH when methyl isobutyl carbinol was used as a second substrate. Continuous production of l-menthol was achieved by using a reactor equipped with a hydrophobic microfiltration membrane. It was found that both NAD(H) and the enzyme could be retained in the reactor and the products, l-methanol and methyl isobutyl ketone, passed through the membrane. The production of l-methanol was maintained for 270 h at a rate of 46.1 g l-1 d-1, and had decreased by one-half at 607 h. The recycling number of NAD(H) was 2500 (max. 3020) during the operation. The number of theoretical plates was calculated to be 40 for the separation of l-menthol from other reactants.

Coenzymes↗
PubMed2026

Deep mutational scan of the pore of the cold-sensing TRPM8 channel.

Members of the Transient Receptor Potential (TRP) family of ion channels have a nearly ubiquitous role in human physiology, tuning cell signaling to remarkably diverse physical and chemical stimuli. Although there is extensive structural data on TRP channels, a systematic and unbiased interrogation of structure-function relations in these proteins is required to fully elucidate their mechanisms of function. By focusing on a critical pore region of the TRPM8 channel, which is the main detector of cold and cooling agents in sensory neurons, we show how deep mutational scanning can be used in combination with the available structural data to understand how TRP channels respond to stimuli. We define a novel mechanism whereby the extracellular pore loop, which has only been resolved in structures representing desensitized states of the channel, plays an essential role in the response of TRPM8 to menthol or cold by coordinating the movement of the S6 helices that line and gate the pore, and the ion-selectivity filter that binds permeant cations. Moreover, our screen reveals sequence determinants along the S6 helices that explain how their architecture sustains gating and, together, provide strong support for a structural mechanism of TRPM8 pore opening in response to menthol and cold.

Journal Article↗
PubMedDate not supplied

Pruritus: a practical approach.

Pruritus is usually caused by a primary disorder of the skin, but can also be caused by a systemic disease (Table 1). Some dermatologic conditions that cause pruritus can be inconspicuous or nonspecific (Table 2), while others are usually apparent on physical examination (Table 3). Classification of pruritus as localized (Fig. 1) vs. generalized (Fig. 3) can be helpful in arriving at a correct diagnosis. The history and physical examination are the most important diagnostic tools, though laboratory testing for systemic disease may be necessary. In refractory cases, one should consider occult systemic disease (such as malignancy), psychiatric disease (especially depression), and HIV infection. Subsequent referral to a dermatologist may be indicted. When treatment of the underlying cause of pruritus is not possible, antihistamines and topical agents (menthol, phenol, and/or pramoxine) can be helpful.

Anal Canal↗
PubMed1992

Antibacterial activity of essential oil components.

Antibacterial activity of fifteen essential oil components towards food borne Staphylococcus sp., Micrococcus sp., Bacillus sp. and Enterobacter sp. was studied by an agar plate technique. Cinnamic aldehyde was the most active compound followed by citral, geraniol, eugenol and menthol. At 500 micrograms/ml, cinnamic aldehyde completely inhibited the bacterial growth for more than 30 days at 30 degrees C that was comparable to 200 micrograms/ml of butylated hydroxy anisole (BHA). At lower temperatures, 25 and 20 degrees C, antibacterial activity of the five essential oil components increased. Addition of sodium chloride at 4% level (w/v) in the medium had no effect on the inhibitory activity of cinnamic aldehyde. In mixtures of cinnamic aldehyde and eugenol or BHA an additive effect was observed.

Acrolein↗
PubMed1976

Effect of inhaling medication vapors from a colds preparation on murine pulmonary bacterial defense systems.

The usefulness of murine pulmonary defense systems as a means for assessing potential toxicity was further confirmed. Recent investigations had indicated that the effects of a chemical agent on mucociliary transport and phagocytic function comprised a sensitive indicator. As one example of such an application, because of the wide usage of proprietary colds preparations containing volatile oils, as well as the use of such oils in various industries, it is important to reassess the potential of such preparations for toxicity when new test systems become available. Mice and rats were exposed to vapors of camphor, menthol, eucalyptol, and turpentine, as contained in a commonly used colds preparation, for 4 and 8 hr prior to challenge with aerosols of radiolabeled Staphylococcus aureus. The exposure system simulated conditions present when the colds preparation is vaporized according to directions for use. Rates of pulmonary bacterial transport and inactivation, as well as of phagocytic ingestion, were determined following exposure to the colds preparation. Each of these rates was unchanged by the treatment. Thus, in this biological system exposure to therapeutic levels of the colds preparation did not impair mucociliary or phagocytic function.

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↗
PubMed1975

Quantitative determination of phenol in ointments.

A quantitative method for the assay of phenol in ointments is described. The procedure involves the formation of a blue indophenol by reacting phenol with 2,6-dibromoquinone-4-chloroimide which can be measured spectrophotometrically. The method is accurate, and interference from other active ingredients (hydrocortisone and menthol) does not occur.

Hydrocortisone↗