Quantification of 1,8‐cineole and of its metabolites in humans using stable isotope dilution assays

The metabolism of 1,8‐cineole after ingestion of sage tea was studied. After application of the tea, the metabolites 2‐hydroxy‐1,8‐cineole, 3‐hydroxy‐1,8‐cineole, 9‐hydroxy‐1,8‐cineole and, for the first time in humans, 7‐hydroxy‐1,8‐cineole were identified in plasma and urine of one volunteer. For quantitation of these metabolites and the parent compound, stable isotope dilution assays were developed after synthesis of [²H₃]‐1,8‐cineole, [9/10‐²H₃]‐2‐hydroxy‐1,8‐cineole and [¹³C,²H₂]‐9‐hydroxy‐1,8‐cineole as internal standards. Using these standards, we quantified 1,8‐cineole by solid phase microextraction GC‐MS and the hydroxyl‐1,8‐cineoles by LC‐MS/MS after deconjugation in blood and urine of the volunteer. After consumption of 1.02 mg 1,8‐cineole (19 μg/kg bw), the hydroxycineoles along with their parent compound were detectable in the blood plasma of the volunteer under study after liberation from their glucuronides with 2‐hydroxycineole being the predominant metabolite at a maximum plasma concentration of 86 nmol/L followed by the 9‐hydroxy isomer at a maximum plasma concentration of 33 nmol/L. The parent compound 1,8‐cineole showed a low maximum plasma concentration of 19 nmol/L. In urine, 2‐hydroxycineole also showed highest contents followed by its 9‐isomer. Summing up the urinary excretion over 10 h, 2‐hydroxycineole, the 9‐isomer, the 3‐isomer and the 7‐isomer accounted for 20.9, 17.2, 10.6 and 3.8% of the cineole dose, respectively.     

Ecological Example of Conditioned Flavor Aversion in Plant–Herbivore Interactions: Effect of Terpenes of Eucalyptus Leaves on Feeding by Common Ringtail and Brushtail Possums

We investigated the hypothesis that feeding deterrence of common ringtail possums (Pseudocheirus peregrinus) and common brushtail possums (Trichosurus vulpecula) by Eucalyptus terpenes (in this case 1,8-cineole) is a result of a conditioned flavor aversion (CFA), due to the association of terpenes with postingestive effects of another group of Eucalyptus toxins, the diformylphloroglucinol compounds (DFPCs). Wild-caught common ringtail and common brushtail possums showed a dose-dependent reduction in food intake when 1,8-cineole was added to the diet. However, after continued exposure over 12 days to increasing amounts of cineole in the diet, both species substantially increased their intakes of cineole relative to control animals. This indicated that the aversion to cineole was a conditioned response rather than a physiological limitation in their ability to detoxify terpenes. Subsequent exposure to a diet including both cineole and jensenone (a simple DFPC also found in Eucalyptus and considered to cause postingestive emesis) in corresponding amounts was able to recondition the dose-dependent aversion. Consequently, animals that had been given jensenone showed an aversion to cineole-rich diets that matched the behavior of animals in the control group. This supported our hypothesis that the effect of terpenes on feeding of these marsupial folivores on Eucalyptus is due to a CFA. Possums can cope with levels of terpenes in the diet that far exceed those occurring naturally. The role of terpenes in marsupial folivore–Eucalyptus interactions appears to be to act as a cue to levels of toxic DFPCs in the leaves, rather than acting as toxins in their own right.     

Antibacterial activities of essential oils and extracts of Turkish Achillea,Satureja and Thymus species against plant pathogenic bacteria

BACKGROUND: The aims of this study were to examine the chemical composition of the essential oils and hexane extracts of the aerial parts of Satureja spicigera (C. Koch) Boiss., Thymus fallax Fisch. & CA Mey, Achillea biebersteinii Afan, and Achillea millefolium L. by GC and GC–MS, and to test antibacterial efficacy of essential oils and n‐hexane, chloroform, acetone and methanol extracts as an antibacterial and seed disinfectant against 25 agricultural plant pathogens. RESULTS: Thymol, carvacrol, p‐cymene, thymol methyl ether and γ‐terpinene were the main constituents of S. spicigera and T. fallax oils and hexane extracts. The main components of the oil of Achillea millefolium were 1,8‐cineole, δ‐cadinol and caryophyllene oxide, whereas the hexane extract of this species contained mainly n‐hexacosane, n‐tricosane and n‐heneicosane. The oils and hexane extracts of S. spicigera and T. fallax exhibited potent antibacterial activity over a broad spectrum against 25 phytopathogenic bacterial strains. Carvacrol and thymol, the major constituents of S. spicigera and T. fallax oils, also showed potent antibacterial effect against the bacteria tested. The oils of Achillea species showed weak antibacterial activity. Our results also revealed that the essential oil of S. spicigera, thymol and carvacrol could be used as potential disinfection agents against seed‐borne bacteria. CONCLUSION: Our results demonstrate that S. spicigera, T. fallax oils, carvacrol and thymol could become potentials for controlling certain important agricultural plant pathogenic bacteria and seed disinfectant. Copyright © 2009 Society of Chemical Industry     

Esters of 1,3,3,-trimethyl-2-oxabicyclo [2.2.2]octan-6-ols: synthesis, odour evaluation and in vitro preliminary toxicity assays

The synthesis of a series of alkyl and arylesters of 1,3,3,-trimethyl-2-oxabicyclo[2.2.2]octan-6-ols (2-cineolylols) is described. All cineole esters obtained were tested for their olfactive character; the esters derived from aryl acyl chlorides were odourless, while aliphatic esters showed interesting multipurpose aromas. Some of these compounds exhibited fruity, woody, green, pine oil and violet-like notes and some showed aromas interesting for foodstuffs. In vitro toxicity tests were carried out on the cyclopropyl ester of 2-cineolylols, the most promising of these compounds as a potential perfume ingredient. In this study, cultured mouse fibroblast L-929 and human keratinocyte NCTC 2544 cell lines were used. The results obtained with the evaluation of three different physiological end points showed that the tested compound possess much lower cytotoxicity than sodium dodecylsulphate (SDS) used as positive control     

Effects of two plant secondary metabolites,cineole and gallic acid,on nightly feeding patterns of the common brushtail possum

We investigated effects of two plant secondary metabolites (PSMs), cineole and gallic acid, on the nightly feeding behavior of the common brushtail possum (Trichosurus vulpecula), a generalist folivore. We tested whether possums altered their feeding behavior in response to increasing levels of cineole, a dietary terpene. Possums were fed artificial diets containing three levels of cineole; zero (basal diet), medium (6.8% of total dry matter, DM), and high (15.3% DM). In another experiment, we introduced gallic acid, a dietary phenolic, into the diets. Possums were offered a Choice PSM diet (cineole and gallic acid diets simultaneously) or a No-Choice PSM diet (containing either cineole or gallic acid). Detoxification products of cineole and gallic acid were examined in urine to determine that different detoxification pathways were utilized in the elimination of each compound. With increasing cineole levels, possums ate less, had smaller feeding bouts, and had a lower rate of intake, but did not extend their total nightly feeding time. Possums offered the Choice PSM diet, compared with the No-Choice diets, ate more, had larger feeding bouts, and tended to increase their rate of intake. Results from the urinary analysis indicated that gallic acid and cineole were not involved in competing detoxification pathways in brushtail possums. There was also a significant sex effect: females ate more overall, ate more per feeding bout, and ate at a higher rate than males. These results indicate that PSMs not only constrain overall intake, but that possums alter their feeding behavior in response to them. Altered feeding patterns may reduce the negative influence of PSMs on intake.     

Baker's yeast-mediated synthesis of endo-2-cineolylol, a starting compound for potential cosmetic odourants

Synopsis
Baker's yeast-mediated reduction of (+)-1,3,3-trimethyl-2-oxabicyclo[2,2,2]octan-6-one yields the corresponding 1,3,3-trimethyl-2-oxabicyclo[2,2,2]octan-6-ol as endo configuration in optically pure form. To study the reaction behaviour we have developed a RP-HPLC method. The synthesis and the olfactive character of some esters obtained from the endo -2-cineolylol are reported. A comparative odour evaluation between these esters and the corresponding compounds synthesized from the endo-exo alcohol mixture was performed.
Résumé
La réduction de (+)-1,3,3-triméthyl-2-oxabicyclo[2,2,2]octan-6-one par la lévure conduit au 1,3,3-triméthyl [2,2,2]octan-6-ol correspondant, de configuration endo avec une forme optique pure. On a développé une méthode RP-HPLC pour enregistrer le comportement de la réaction. La synthèse et le caractère olfactif des esters obtenus de cet alcool sont rapportés.. On a comparé l'évaluation de l'odeur de ces composés avec celle des composés correspondants, dérivés du mélange endo-eso des alcools.     

硬糖类产品中桉叶素的含量测定

目的建立适用于硬糖类产品中桉叶素的检测方法。方法采用气相色谱法测定硬糖中桉叶素的含量。采用Agilent HP-INNOWAX毛细管色谱柱(柱长为30 m,内径为0.32 mm,膜厚为0.25μm),采用顶空进样,进样量为5mL,炉温为85℃,平衡时间为30min,进样口温度为150℃,柱温为程序升温:初始温度70℃,以5℃/min的升温速率升温至125℃,保持2min,再以20℃/min的升温速率升温至200℃,保留5min;检测器温度为180℃,载气流速为1.0mL/min。结果桉叶素回归方程Y=8622.2X-32.028,相关系数r2为0.9998,线性范围为0.00284~0.56720mg/mL,加样回收率为104.31%。结论该法简便、准确、专属性强、重复性好,经方法学验证,本法可用于硬糖类产品中桉叶素的含量测定。     

Synthesis of quaternary ammonium bromides of 5-[4-(ω-dialkylaminoalkoxy)phenyl-methylene]-1, 3, 3-trimethyl-2-oxabicyclo [2.2.2]octan-6-ones as potential UV sunscreens

Materials and methods for the synthesis of eight quaternary ammonium bromides of 5-[4-(ω-dialkylaminoalkoxy)phenylmethylene]-1,3,-trimethyl-2-oxabicyclo[2.2.2]octan-6-ones are illustrated. They were routinely prepared starting from cineole aminoethers by reaction with primary alkyl bromides and their physico-chemical data are reported. These substances have been tested for UV filtering and/or microbiological activity. The substances have their UV absorption maxima at 315–322 nm. Tests on antimicrobial activity were performed using benzalkonium chloride as reference standard. All quaternary ammonium bromides were totally inactive against Escherichia coli (Gram —) and partially active on Staphylococcus aureus (Gram +). These preliminary findings seem to indicate that these new quaternary ammonium bromides could be considered as potential UV sunscreens.     

Interference of sonic communication and mating in leafhopperAmrasca devastans (distant) by certain volatiles

Mating between the two sexes in the leafhopperAmrasca devastans was inhibited by cineole vapors surrounding host plant leaves bearing the insects. There was a decline in the percentage of pairs mating and mated females fertilized. The vapors were not toxic and did not prevent the insects' arrival on the leaves. The cineole vapors inhibited the mating chiefly by interfering with the surface-mediated sonic communication between the sexes. The inhibition of mating was chemical specific since other volatiles, e.g., citral, were not as effective as cineole. Exposure to cineole vapors resulted in a decline in the sexual response of the females to the sonic signals of the male     

具有除草活性的1,4-桉树脑衍生物的研究进展

1，4-桉树脑衍生物是一类具有良好除草活性的化合物。概述了具有烷氧基、取代苯氧基、取代苄氧基以及杂(并)环氧基四种结构类型桉树脑类衍生物的结构与除草活性的关系，阐述了取代基的变化对除草活性的影响以及它们作为苗前和苗后除草剂的应用效果。此外，还介绍了1，4-桉树脑衍生物除草作用机理的研究动态，研究表明，1，4-桉树脑衍生物可作为天冬酰胺合成酶抑制剂。