1.1,8- and 1,4-cineole enhance spontaneous excitatory transmission by activating different types of TRP channels in the rat spinal substantia gelatinosa.
Jiang CY1, Wang C1, Xu NX1, Fujita T1, Murata Y2, Kumamoto E1. J Neurochem. 2015 Nov 18. doi: 10.1111/jnc.13433. [Epub ahead of print]
Although TRP channels expressed in the spinal substantia gelatinosa (SG) play a role in modulating nociceptive transmission, their properties have not been fully examined yet. In order to address this issue, the effects of 1,8-cineole and its stereoisomer 1,4-cineole on excitatory transmission were examined by applying the whole-cell patch-clamp technique to SG neurons in adult rat spinal cord slices. Miniature excitatory postsynaptic current (EPSC) frequency was increased by 1,8- and 1,4-cineole. The cineole activities were repeated and resistant to voltage-gated Na+ -channel blocker tetrodotoxin. The 1,8-cineole activity was inhibited by TRPA1 antagonists (HC-030031 and mecamylamine) but not TRPV1 antagonists (capsazepine and SB-366791), whereas the 1,4-cineole activity was depressed by the TRPV1 but not TRPA1 antagonists. Although 1,8- and 1,4-cineole reportedly activate TRPM8 channels, their activities were unaffected by TRPM8 antagonist BCTC.
2.Investigation and Sensory Characterization of 1,4-Cineole: A Potential Aromatic Marker of Australian Cabernet Sauvignon Wine.
Antalick G, Tempère S1,2, Šuklje K, Blackman JW, Deloire A, de Revel G1,2, Schmidtke LM. J Agric Food Chem. 2015 Oct 21;63(41):9103-11. doi: 10.1021/acs.jafc.5b03847. Epub 2015 Oct 8.
This work reports the quantitation and sensory characterization of 1,4-cineole in red wine for the first time. A headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method was developed to quantitate 1,4-cineole and 1,8-cineole in 104 commercial Australian red wines. 1,4-Cineole was detected in all of the wines analyzed, with concentrations ranging from 0.023 to 1.6 μg/L. An important varietal effect was observed, with concentrations of 1,4-cineole in Cabernet Sauvignon wines (mean of 0.6 ± 0.3 μg/L) significantly higher than in Shiraz (0.07 ± 0.04 μg/L) and Pinot Noir (0.2 ± 0.2 μg/L) wines. Regional variations of both cineole isomer concentrations have been measured between wines originating from different Australian regions. Sensory studies demonstrated that the addition of 0.54 μg/L 1,4-cineole in a Cabernet Sauvignon wine, to produce a final concentration of 0.63 μg/L, was perceived significantly by a sensory panel (p < 0.
3.Toxicity of Rhododendron anthopogonoides essential oil and its constituent compounds towards Sitophilus zeamais.
Yang K1, Zhou YX, Wang CF, Du SS, Deng ZW, Liu QZ, Liu ZL. Molecules. 2011 Aug 25;16(9):7320-30. doi: 10.3390/molecules16097320.
The screening of several Chinese medicinal plants for insecticidal principles showed that essential oil of Rhododendron anthopogonoides flowering aerial parts possessed significant toxicity against maize weevils, Sitophilus zeamais. A total of 37 components were identified in the essential oil and the main constituents of the essential oil were 4-phenyl-2-butanone (27.22%), nerolidol (8.08%), 1,4-cineole (7.85%), caryophyllene (7.63%) and γ-elemene (6.10%), followed by α-farnesene (4.40%) and spathulenol (4.19%). Repeated bioactivity-directed chromatographic separation on silica gel columns led us to isolate three compounds, namely 4-phenyl-2-butanone, 1,4-cineole, and nerolidol. 4-Phenyl-2-butanone shows pronounced contact toxicity against S. zeamais (LD₅₀ = 6.98 mg/adult) and was more toxic than either 1,4-cineole or nerolidol (LD₅₀ = 50.86 mg/adult and 29.30 mg/adult, respectively) against the maize weevils, while the crude essential oil had a LD₅₀ value of 11.
4.Inhibition by menthol and its related chemicals of compound action potentials in frog sciatic nerves.
Kawasaki H1, Mizuta K, Fujita T, Kumamoto E. Life Sci. 2013 Mar 14;92(6-7):359-67. doi: 10.1016/j.lfs.2013.01.012. Epub 2013 Jan 24.
AIMS: Transient receptor potential (TRP) vanilloid-1 (TRPV1) and melastatin-8 (TRPM8) channels play a role in transmitting sensory information in primary-afferent neurons. TRPV1 agonists at high concentrations inhibit action potential conduction in the neurons and thus have a local anesthetic effect. The purpose of the present study was to know whether TRPM8 agonist menthol at high concentrations has a similar action and if so whether there is a structure-activity relationship among menthol-related chemicals.