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PubMed1989

Hepatotoxicity of pulegone in rats: its effects on microsomal enzymes, in vivo.

Oral administration of pulegone (400 mg/kg) to rats once daily for five days caused significant decreases in the levels of liver microsomal cytochrome P-450 and heme. Cytochrome b5 and NAD(P)H-cytochrome c-reductase activities were not affected. Massive hepatotoxicity accompanied by an increase in serum glutamate pyruvate transaminase (SGPT) and a decrease in glucose-6-phosphatase were observed upon treatment with pulegone. A significant decrease in aminopyrine N-demethylase was also noticed after pulegone administration. Menthone or carvone (600 mg/kg), compounds related to pulegone, when administered orally did not cause any decrease in cytochrome P-450 levels. The hepatotoxic effects of pulegone were both dose and time dependent. Pretreatment of rats with phenobarbital (PB) or diethylmaleate (DEM) potentiated the hepatotoxicity caused by pulegone, whereas, pretreatment with 3-methylcholanthrene (3-MC) or piperonyl butoxide protected from it. It appears that a PB induced cytochrome P-450 catalysed reactive metabolite(s) may be responsible for the hepatotoxicity caused by pulegone.

Alanine Transaminase↗
PubMed1987

Spectrophotometric determination of cation concentrations in olfactory mucus.

Spectrophotometric techniques were used to determine the concentrations of Na+, K+ and Ca2+ in the olfactory mucus of frogs. The mean concentrations in mEq/l were: [Na+], 52.7 +/- 4.1; [K+], 10.6 +/- 1.9 and [Ca2+], 10.7 +/- 1.7. Topical application of the odorant cineole was associated with statistically significant increases in [Na+] and [Ca2+]; the secretagogues methacholine and isoproterenol induced transient increases in [Na+]. Cineole and methacholine caused sustained increases in [Na+]/[K+] from the control value of 5:1, while isoproterenol caused a transient increase followed by a decline. The results indicate that the cation concentrations in olfactory mucus samples are more similar to those derived from secretory tissue than to those found in the extracellular fluids surrounding typical neural tissue.

Animals↗
PubMed1994

Inhalation of vapor from black pepper extract reduces smoking withdrawal symptoms.

Previous studies have suggested that sensory cues associated with cigarette smoking can suppress certain smoking withdrawal symptoms, including craving for cigarettes. In this study we investigated the subjective effects of a cigarette substitute delivering a vapor of black pepper essential oil. Forty-eight cigarette smokers participated in a 3-h session conducted after overnight deprivation from smoking. Subjects were randomly assigned to one of three conditions: one group of smokers puffed on a device that delivered a vapor from essential oil of black pepper; a second group puffed on the device with a mint/menthol cartridge, and a third group used a device containing an empty cartridge. Subjects puffed and inhaled ad libitum from the device throughout the session during which no smoking was allowed. Reported craving for cigarettes was significantly reduced in the pepper condition relative to each of the two control conditions. In addition, negative affect and somatic symptoms of anxiety were alleviated in the pepper condition relative to the unflavored placebo. The intensity of sensations in the chest was also significantly higher for the pepper condition. These results support the view that respiratory tract sensations are important in alleviating smoking withdrawal symptoms. Cigarette substitutes delivering pepper constituents may prove useful in smoking cessation treatment.

Administration, Inhalation↗
PubMedDate not supplied

Short-term toxicity study in rats dosed with menthone.

Menthone, a component of peppermint oil, was given p.o. to groups of 10 male and 10 female rats at dose levels of 0, 200, 400 and 800 mg/kg b.w./day, respectively, for 28 days. After 19 days the dose was reduced to 400 mg/kg b.w. in the female group receiving the highest dose. Analyses of plasma showed a dose-dependent decrease in creatinine content and a dose-dependent increase in alkaline phosphatase activity and bilirubin. The relative weights of liver and spleen were increased. Cyst-like spaces were seen histopathologically in the white matter of the cerebellum of the two highest dose groups. The no-effect level for menthone in this study was lower than 200 mg/kg b.w./day.

Animals↗
PubMed1995

Induction of protein droplet (alpha 2 mu-globulin) nephropathy in male rats after short-term dosage with 1,8-cineole and l-limonene.

As part of a series of short-term studies on peppermint oil constituents for their possible induction of the encephalopathy found with peppermint oil, 1,8-cineole and l-limonene were studied. Groups of 10 male Wistar rats were given 0, 500, or 1000 mg 1,8-cineole/kg body wt./day or 0, 800, or 1600 mg l-limonene/kg body wt./day for 28 days. 1,8-Cineole and l-limonene both induced accumulation of protein droplets containing alpha 2 mu-globulin in proximal tubular epithelial cells in male rats. These results suggest that both 1,8-cineole and l-limonene possibly belong to the group of chemicals characterized by their induction of excessive alpha 2 mu-globulin accumulation. Neither of the 2 substances induced encephalopathy.

Alpha-Globulins↗
PubMed1996

Gas chromatographic-mass spectrometric method to characterise the transfer of dietary odorous compounds into plasma and milk.

The flavours contained in a mammalian mother's milk can exert a marked influence on her offspring's proximate suckling behaviour and later preferences. The aim of this study was to establish a reliable analytical procedure to characterise the mammary transfer of selected volatile constituents of maternal food from non-pregnant and recently parturient ewes. Six known volatile compounds, most representative of cumin aroma (alpha-pinene, gamma-terpinene, cuminaldehyde, p-cymene, limonene and cineole), were traced in the blood and milk of ewes fed with cumin seeds, using liquid-liquid extraction combined with gas chromatography-specific ion monitoring mass spectrometry. Among the six cumin odour markers, only one, p-cymene, was transferred in quantifiable amounts into the venous plasma. The other cumin markers could only be detected as traces corresponding to amounts lower that the limit of quantification. In milk, four of the cumin markers could be detected, and two of these were quantified.

Animals↗
PubMed1990

In vitro antibacterial activities of three plants used in traditional medicine in Sierra Leone.

The antibacterial activities of the methanol and hot and cold aqueous extracts of the leaves of Aspilia africana, Ficus exasperata and Mareya micrantha were bioassayed against three Gram-negative and three Gram-positive bacterial species: Aerobacter aerogenes, Agrobacterium tumefaciens, Bacillus subtilis, Clostridium sporogenes, Escherichia coli and Staphylococcus aureus. The methanol and aqueous extracts of the leaves of Aspilia africana and Mareya micrantha and the undiluted oil of M. micrantha exhibited differential antibacterial activities on both Gram-positive and Gram-negative bacterial species at concentrations ranging from 0.1 to 0.5 g/ml. Extracts of Ficus exasperata leaves were inactive at all concentrations tested.

Anti-Bacterial Agents↗
PubMed2006

Analgesia mediated by the TRPM8 cold receptor in chronic neuropathic pain.

BACKGROUND: Chronic established pain, especially that following nerve injury, is difficult to treat and represents a largely unmet therapeutic need. New insights are urgently required, and we reasoned that endogenous processes such as cooling-induced analgesia may point the way to novel strategies for intervention. Molecular receptors for cooling have been identified in sensory nerves, and we demonstrate here how activation of one of these, TRPM8, produces profound, mechanistically novel analgesia in chronic pain states. RESULTS: We show that activation of TRPM8 in a subpopulation of sensory afferents (by either cutaneous or intrathecal application of specific pharmacological agents or by modest cooling) elicits analgesia in neuropathic and other chronic pain models in rats, thereby inhibiting the characteristic sensitization of dorsal-horn neurons and behavioral-reflex facilitation. TRPM8 expression was increased in a subset of sensory neurons after nerve injury. The essential role of TRPM8 in suppression of sensitized pain responses was corroborated by specific knockdown of its expression after intrathecal application of an antisense oligonucleotide. We further show that the analgesic effect of TRPM8 activation is centrally mediated and relies on Group II/III metabotropic glutamate receptors (mGluRs), but not opioid receptors. We propose a scheme in which Group II/III mGluRs would respond to glutamate released from TRPM8-containing afferents to exert an inhibitory gate control over nociceptive inputs. CONCLUSIONS: TRPM8 and its central downstream mediators, as elements of endogenous-cooling-induced analgesia, represent a novel analgesic axis that can be exploited in chronic sensitized pain states.

Acrolein↗
PubMed2003

Crystal structure of amylose complexes with small ligands.

Amylose complexes were prepared, as lamellar single crystals and polycrystalline powders, from aqueous solutions by adding small flavor molecules. The morphology, crystal structure, and thermal properties of complexes with fenchone, menthone, and geraniol were determined using transmission electron microscopy, wide-angle X-ray diffraction, and differential scanning calorimetry. The crystal structure was found to be similar to that of V amylose complexes with isopropanol. This implies that the crystallosolvates contain sixfold helices packed in orthorhombic unit cells, with the ligands possibly lying in the interhelical space. Different drying procedures were also studied leading to less resolved X-ray diagrams. The thermoanalysis confirmed that complexes with a relatively high crystallinity were formed.

2-Propanol↗
PubMed2004

Structural investigation of amylose complexes with small ligands: inter- or intra-helical associations?

Highly crystalline amylose complexes with menthone (1) and linalool (2) were analysed by wide-angle X-ray diffraction and solid-state nuclear magnetic resonance (NMR). The complexes, after partial water desorption in a controlled atmosphere (aw=0.75), displayed a typical V-isopropanol structure, showing the presence of ligand inside or between the helices in the crystalline domains. Sequential washing of the powdered complexes with ethanol before and after desorption permitted probing the intra- and inter-helical inclusions. High resolution magic angle spinning (HRMAS) recordings were used to compare the chemical shifts of free and bound aroma which allowed a proposal that some hydrogen bonding is involved in the amylose complexing. Moreover, it showed that free aroma was completely removed by ethanol washing. Using cross polarization magic angle spinning (CPMAS) and X-ray scattering experiments, it was demonstrated that the V-isopropanol type was retained for linalool whatever the treatment used. On the contrary, the measurement shifts toward the V-6I amylose hydrate (V-h) type for menthone after ethanol washing before the desorption step, reflecting the disappearance of inter-helical associations between menthone and amylose. The stability of the complex prepared with linalool shows that this ligand is more strongly associated to amylose helices. The discrepancies observed in the chemical shifts attributed to carbons C1 and C4 in CPMAS spectra of V-isopropanol and V-h forms could be attributed either to a deformation of the single helix (with possible inclusion of the ligand inside) or to the presence of the ligand between helices (only water molecules are present in the V-h form).

Acyclic Monoterpenes↗
PubMed2005

Cutaneous bioassay of salicylic acid as a keratolytic.

Keratolytic efficacy of topical preparations containing salicylic acid was studied in humans utilizing adhesive tape stripping and quantifying SC removal by protein analysis. In combination with tape stripping, squamometry was used to evaluate the influence of salicylic acid on skin surface scaliness and desquamation. Furthermore, skin barrier perturbation and skin irritancy was recorded and related to the dermatopharmacological effect of the preparations. In contrast to squamometry, tape stripping combined with protein analysis was sensitive in detecting keratolytic effect of salicylic acid within hours of application. Importantly, whereas the pH of the preparations only minimally influenced efficacy, local dermatotoxicity was significantly increased at acidic pH. This indicates that the quest to increase the amount of free, non-dissociated SA is, in fact, counterproductive as the more acidic preparations resulted in skin irritation and barrier disruption.

Administration, Cutaneous↗
PubMed2006

The effect of terpene concentrations on the skin penetration of diclofenac sodium.

Terpenes and sesquiterpenes have been suggested as promising non-toxic, non-irritating transdermal penetration enhancers. This investigation aimed to study the effect of terpene concentration on the transdermal absorption of diclofenac sodium from ethanol:glycerin:phosphate buffer solution (60:10:30). Therefore, enhancing effects of various terpenes (menthone, limonenoxide, carvone, nerolidol and farnsol) with different concentrations (0.25, 0.5, 1, 1.5 and 2.5%, v/v) on the permeation of diclofenac sodium were evaluated using Franz diffusion cells fitted with rat skin. Furthermore, solubility of diclofenac sodium in the vehicle in presence of different concentrations of terpenes was determined. The results showed that despite the negligible effect of terpenes on the drug solubility, there was a profound skin penetration enhancement effect, although the terpene enhancers varied in their ability to enhance the flux of diclofenac sodium. The results showed that at the highest concentration of terpene (2.5%, v/v) the rank order of enhancement effect for diclofenac sodium was nerolidol>farnesol>carvone>methone>limonenoxide, whereas at the low concentration of 0.25% the rank order was farnesol>carvone>nerolidol>menthone>limonenoxide. No direct relationship existed between terpene concentration and the permeation rate. The most outstanding penetration enhancer was nerolidol, providing an almost 198-fold increase in permeability coefficient of diclofenac sodium, followed by farnesol with a 78-fold increase.

Administration, Cutaneous↗
PubMed1990

Biotransformations of R-(+)-pulegone and menthofuran in vitro: chemical basis for toxicity.

Incubation of R-(+)-pulegone(I) with PB-induced rat liver microsomes in the presence of NADPH resulted in the formation of menthofuran (II) and 2-Z-[2'-keto-4'-methylcyclohexylidene] propanol (III, 9-hydroxy pulegone) as the major and minor metabolites, respectively. When isopulegone (IV) was used as the substrate, the major metabolite formed was shown to have identical GC-MS fragmentation pattern to that of synthetic 2-[2'-keto-4'-methylcyclohexyl]prop-2-en-1-ol (V) and the minor metabolite was shown to be menthofuran (II). Transformation of menthofuran (II) by microsomes in the presence of NADPH yielded a metabolite identified as 2-Z-(2'-keto-4'-methyl cyclohexylidene) propanal (VI, pulegone-8-aldehyde). Formation of this alpha, beta -unsaturated aldehyde was further confirmed by trapping it as cinnoline derivative by adding semicarbazide to the assay medium. The toxicity mediated by pulegone is discussed in the light of these observations.

Animals↗
PubMed1998

Fast wave activity in the rat rhinencephalon: elicitation by the odors of phytochemicals, organic solvents, and a rodent predator.

Recent research has shown that bursts of approximately 20 Hz fast waves are elicited in rhinencephalic cortex in rats by the odors of a number of different organic solvents and of components of the secretions of predators such as the weasel and the fox. We now show that a number of phytochemicals (benzyl alcohol, carvacrol, eucalyptol, and salicylaldehyde) will elicit fast wave bursts of about 20 Hz in the rat pyriform cortex. Additional organic solvents (carbon tetrachloride, chloroform, diethyl ether, 1, 2-dimethoxyethane, n-heptane, mesitylene, methylcyclohexane, and commercial gasoline and kerosene, but not N,N-dimethylformamide or dimethyl sulfoxide) and another component of fox secretions (isopentenylmethyl sulfide) were also effective. Many of these compounds will also elicit fast wave bursts of about 20 Hz in the dentate gyrus. The effectiveness of benzyl alcohol, camphor, carvacrol, eucalyptol, isopentenylmethyl sulfide, 2-propylthietane, salicylaldehyde, toluene, and trimethylthiazoline (all of which elicit rhinencephalic fast waves in rats) in suppressing feeding in various small herbivores suggests that the recording of odor-induced rhinencephalic fast waves may provide an easy means of identifying new antifeedants. We found no evidence that the bursts of 20-Hz activity seen in the rat rhinencephalon were kindling-induced seizure-like reactions of the olfactory brain to the vapors of toxic chemicals.

Aldehydes↗
PubMed1997

Mast cell involvement in the rat paw oedema response to 1,8-cineole, the main constituent of eucalyptus and rosemary oils.

The present studies tested the ability of 1,8-cineole to produce inflammatory oedema in the hind paw of the rat and verified the possible involvement of mast cells in the response. Subplantar injection of 1,8-cineole (10, 15 and 20 microl/paw) induced a dose-dependent paw oedema which was apparent within 30 min. At higher doses the oedema effect was persistent, peaked at 2 h, and then decreased gradually but was still pronounced at 24 h post injection. In contrast, the oedema produced by mast cell degranulator compound 48/80 (10 microg/paw) had a rapid onset with a peak effect at the first hour, followed by a gradual decrease thereafter and at 24 h post injection it was almost absent. The oedema response to 20 microl 1,8-cineole was significantly inhibited throughout its time-course in rats pretreated with antihistaminic and antiserotonergic drugs such as diphenhydramine, methysergide and cyproheptadine or with ketotifen, a mast cell stabilizer. A more effective blockade of the oedema response was, however, observed in rats depleted of mast cell granules by systemic treatment with compound 48/80. Furthermore, 1,8-cineole was able to cause rat peritoneal mast cell degranulation (94%) in vitro, in a concentration as low as 0.3 microl/ml, which was almost comparable to that produced by 0.1 microg/ml of compound 48/80. The data provide evidence of a key role for the mast cell in 1,8-cineole-induced hind paw oedema in the rat.

Animals↗