Showing papers on "Terpene published in 1993"

Metabolic fate of dietary terpenes from Eucalyptus radiata in common ringtail possum ( Pseudocheirus peregrinus )

Abstract: Arboreal marsupials consume terpenes in quantities that are toxic to other mammals, indicating that they possess special detoxification mechanisms. The metabolic fate of dietary terpenes was studied in the common ringtail possum (Pseudocheirus peregrinus). Three animals were fedEucalyptus radiata leaf for 10 days. Leaf consumption increased over three days to an average steady state of about 10-15 mmol total terpenes per day. GCMS analysis identified six urinary terpene metabolites, which were dicarboxylic acids, hydroxyacids, or lactones. Another nine metabolites could only be shown to be terpene-derived but of unknown structure. The amounts excreted were estimated by GC-FID, using response factors based on carbon content. Total 24-hr excretion of terpene-derived metabolites increased to 6.2-7.6 mmol on days 5-10, while glucuronic acid excretion remained constant at about 1.5 mmol. No other conjugates of terpene metabolites were found. The strategy used by the possum to detoxify dietary terpenes seems to be to polyoxygenate the molecules forming highly polar, acidic metabolites that can be readily excreted. Conjugation is minimal, perhaps to conserve carbohydrate and amino acids.

The effect of a long‐term water stress on the metabolism and emission of terpenes of the foliage of Cupressus sempervirens

Abstract: The effects of long-term water stress on water and terpene contents of the foliage of Cupressus sempervirens were studied. A great deal of water was lost over 2 months before a remarkable stabilization. A strong decrease of all the classes of terpenes accompanied this dehydration. Mono- and sesquiterpene hydrocarbons and free terpenols were almost entirely metabolized, whereas esters and terpene glycosides rose slightly and remained at a constant level when the water content had stabilized. Although a significant part of the mono- and sesquiterpene hydrocarbons was emitted in the early stage of stress application, the major part was used by the plant in response to the drought conditions.

Response on the ground of bark beetle and weevil species colonizing conifer stumps and roots to terpenes and ethanol

Abstract: Responses of threeHylastes species,Dryocoetes autographus, and twoHylobius species to terpenes and ethanol were studied in field experiments on clear-cut forest sites in Sweden using baited ground traps.α-Pinene alone did not attract any of the six species. A terpene blend (spruce turpentine consisting mainly ofα-pinene,β-pinene, and 3-carene) attractedHylastes cunicularius, H. brunneus, andHylobius abietis in some experiments, but not in others. The attractiveness of ethanol also varied; the only species consistently attracted wasH. abietis. Baits containing both terpenes and ethanol, particularly the combination of spruce turpentine and ethanol, were attractive to all species exceptHylobius pinastri. InH. abietis, the terpene plus ethanol/ ethanol catch ratios increased during early summer. Seasonal differences in catch levels were observed inH. cunicularius andH. abietis. The addition ofα-pinene reduced the attractiveness of the combination of spruce turpentine and ethanol toH. cunicularius, H. opacus, andD. autographus. The differences in response to the volatiles between species are probably related to differences in reproductive behavior and host preferences.

The essential oil of Rhus coriaria L. fruits

Abstract: The steam volatile constituents of the oriental spice sumac, the dry fruits of Rhus coriaria L., were analysed by GC and GC–MS. During comparative studies with plant material from six Turkish provinces, more than 120 substances could be identified. Main constituents are terpene hydrocarbons (i.e. α-pinene, β-caryophyllene and cembrene), oxygenated terpenes (i.e. α-terpineol, carvacrol and β-caryophyllene alcohol) as well as farnesyl acetone, hexahydrofarnesylacetone and aliphatic aldehydes. In addition, the fatty acids of the seed fat have been analysed as their methyl esters.

Evaluation of Skin Damage of Cyclic Monoterpenes, Percutaneous Absorption Enhancers, by Using Cultured Human Skin Cells

Abstract: The cytotoxicity of monoterpenes, percutaneous absorption enhancers, to cultured human skin cells was investigated in order to quantitatively estimate their skin damage. A neutral red bioassay with epidermal keratinocytes and a contraction test of collagen gel in which dermal fibroblasts were cultured were employed for evaluating the cytotoxicity of terpenes. In the neutral red bioassay, keratinocyte proliferation was inhibited on the addition of terpenes, and cell survival remarkably decreased with an increase in the concentration of terpenes fed into the culture well. When the fibroblasts were cultured in a collagen gel matrix, the lattice of collagen contracted as the cells grew. Therefore, the application of cytotoxic agents brings about an inhibition of collagen gel contraction induced by the fibroblasts. Strong inhibition was observed in the cases of hydrocarbons in terpenes, and the inhibition was dependent on the concentration of these compounds added in the culture medium. The cytotoxicity of terpenes was compared with the skin damage evoked by the application of terpenes in rats in vivo. As a result, it was considered that the skin irritation caused by terpenes was predictable to a certain extent by means of the cytotoxic study of cultured human skin cells.

ESSENTIAL OIL OF Protium unifoliolatum (BURSERACEAE)

Abstract: The major constituents of the leaf essential oil of P. unifoliolatumare trans-caryophyllene (37.45%), limonene (24.23%) and α-humulene (9.94%).

Fluorinated terpene compounds

Abstract: Fluorinated terpenes useful in a wide variety of general cleaning and degreasing applications are disclosed. These compounds have high solvencies but reduced flash points, and include derivatives of paracymene and myrcene, both of which, while relatively unreactive, are nonetheless miscible with a wide variety of hydrocarbon soils. The compounds exhibit flash points of 25° F. or more above those of the unmodified terpenes.

Substituted-acyclic terpene compound

Abstract: Acyclic terpene compounds useful as intermediates or producing sarcophytol A which have an anti-carcinogenic promotor activity and anti-tumor activity, which compounds are shown by the general formula (I): ##STR1##

Convenient Synthesis of Decalin Systems of Bioactive Terpenoids.

Abstract: New analogues of bioactive terpenoids, forskolin, nimbolide, isozonarol and ambrox have been synthesized using general Diels-Alder reaction of 2-formyl-4,4-dimethyl-cyclohexa-2,5-dienone (7) with 1,2-disubstituted-1,3-dienes (8a–k) which yielded endo- & exo-adducts. The deformylation, epimerisation, angular methylation, reduction and oxidation studies on these adducts have been reported.