Syntheses and odor of "bulky group"-modified sandalwood odorants: isophorono-beta-santalol analogues.

Three osmophoric points have been found to be necessary for the scent of sandalwood odorants. One of these points is the bulky group in a certain distance from the osmophoric hydroxyl group. Such a hydrophobic moiety is part of the trimethylcyclopentenyl derivatives, the so called campholenals, among them many are known to exert a strong and long lasting sandalwood odor. In continuation of our SAR-studies of sandalwood odorants four isophorone analogues of beta-santalol have been synthesized. The hydrophobic region of these new isophorone derivatives is now a trimethylcyclohexene nucleus, so to speak an extension of the cyclopentene part of the campholenals by one methylene group. This modification changes the sandalwood odor drastically to woody odor notes, reminiscent only to sandalwood odor. The environs of the crowded trimethylcyclohexene nucleus demonstrate the sensitivity of sandalwood odor on the shape of the hydrophobic, bulky part of beta-santalol analogues.

Prediction of the aroma quality and the threshold values of some pyrazines using artificial neural networks.

An artificial neural network is used to predict both the classification of aroma compounds and their flavor impression threshold values for a series of pyrazines. The classification set consists of 98 compounds (32 green, 43 bell-pepper, and 23 nutty smelling pyrazines), and the regression sets consist of 24 green and 37 bell-pepper odorous pyrazines. The best classification of the three aroma impressions (93.7%) is obtained by using a multilayer perceptron network architecture. To predict the threshold values of bell-pepper fragrance, a standard Pearson R correlation coefficient of 0.936 for the training set, 0.912 for the verification set, and 0.926 for the test set is received with two hidden layers consisting of two and one neurons. The network for the threshold prediction of the class of green-smelling pyrazines with one hidden layer containing three neurons turns out to be the best with a standard Pearson R correlation coefficient of 0.859 for the training, 0.918 for the verification, and 0.948 for the test set. These good correlations show that artificial neural networks are versatile tools for the classification of aroma compounds.

Fragrance compounds and essential oils with sedative effects upon inhalation.

Fragrance compounds and essential oils with sedative effects influence the motility of mice in inhalation studies under standardized conditions. A significant drop in the motility of mice was registered following exposure to these fragrances. The same results were achieved when the mice were artificially induced into overagitation by intraperitoneal application of caffeine and subsequently subjected to inhalation of fragrance compounds and essential oils. These results proved the sedative effects of these fragrants via inhalative exposure in low concentrations. Blood samples were taken from the mice after a 1-h inhalation period. Chromatographic and spectroscopic methods were used to detect and characterize the actual effective compounds after solid-phase extraction. Serum concentrations of 42 different substances, including fragrance compounds, were found in low ranges (ng/mL serum). The results contribute to the correct interpretation of the term aromatherapy (i.e., a stimulating or sedative effect on the behaviour of individuals only upon inhalation of fragrance compounds).

Synthesis and olfactoric activity of side-chain modified beta-santalol analogues.

Three osmophoric points have been postulated to be necessary for the sandalwood scent of beta-santalol derivatives. One of these points, close to the hydroxyl group, is highly specific on the stereochemistry and, in particular, on the molecular shape. The role of the 2-methyl group in the side chain of beta-santalol derivatives was studied by replacement through a hydrogen atom, an ethyl or an isopropyl group. It turns out that any change at the 2-methyl substituent leads to the complete loss of sandalwood odour.

Threshold-based structure-activity relationships of pyrazines with bell-pepper flavor.

Quantitative structure activity relationships (QSAR) and comparative molecular field analysis (CoMFA) are applied in order to explain the aroma of 46 bell-pepper aroma compounds. Biological activities log(1/c) values are used, where c stands for the detection threshold value of the aroma compound in water. Results of conventional QSAR and CoMFA are both satisfactory in statistical significance and predictive ability. We construct a qualitative model using the graphic features of CoMFA together with the results of "classical" QSAR analysis, which is performed by multiple linear regression. Finally, the human olfactory detection threshold values of excluded pyrazines are successfully predicted. This makes CoMFA and QSAR two important tools for designing new aroma compounds and in elucidating the mechanism of odor-receptor interaction.

Percutaneous absorption of the montoterperne carvone: implication of stereoselective metabolism on blood levels.

The purpose of this study was to determine whether an enantioselective difference in the metabolism of topically applied R-(-)- and S-(+)-carvone could be observed in man. In a previous investigation we found that R-(-)- and S-(+)-carvone are stereoselectively biotransformed by human liver microsomes to 4R,6S-(-)- and 45,6S-(+)-carveol, respectively, and 4R,6S-(-)-carveol is further glucuronidated. We therefore investigated the metabolism and pharmacokinetics of R-(-)- and S-(+)-carvone in four healthy subjects using chiral gas chromatography as the analytical method. Following separate topical applications at a dose of 300 mg, R-(-)- and S-(+)-carvone were rapidly absorbed, resulting in significantly higher Cmax levels for S-(+)-carvone (88.0 vs 23.9 ng mL(-1)) and longer distribution half-lives (t(1/2alpha)) (19.4 vs 7.8 min), resulting in 3.4-fold higher areas under the blood concentration-time curves (5420 vs 1611 ng min mL(-1)). The biotransformation products for both enantiomers in plasma were below detection limit. Analysis of control- and beta-glucuronidase pretreated urine samples, however, revealed a stereoselective metabolism of R-(-)-carvone to 4R,6S-(-)-carveol and 4R,6S-(-)-carveol glucuronide. No metabolites could be found in urine samples after S-(+)-carvone application. These data indicate that stereoselectivity in phase-I and phase-II metabolism has significant effects on R-(-)- and S-(+)-carvone pharmacokinetics. This might serve to explain the increased blood levels of S-(+)-carvone.

Stereoselective metabolism of the monoterpene carvone by rat and human liver microsomes.

The large amounts of carvone enantiomers consumed as food additives and in dental formulations justifies the evaluation of their biotransformation pathway. The in-vitro metabolism of R-(-)- and S-(+)-carvone was studied in rat and human liver microsomes using chiral gas chromatography. Stereoselective biotransformation was observed when each enantiomer was incubated separately with liver microsomes. 4R, 6S-(-)-Carveol was NADPH-dependently formed from R-(-)-carvone, whereas 4S, 6S-(+)-carveol was produced from S-(+)-carvone. Metabolite formation followed Michaelis-Menten kinetics exhibiting a significant lower apparent Km (Michaelis-Menten Constant) for 4R, 6S-(-)-carveol compared with 4S, 6S-(+)-carveol in rat and human liver microsomes (28.4+/-10.6 microM and 69.4+/-10.3 microM vs 33.6+/-8-55 microM and 98.3+/-22.4 microM). The maximal formation rate (Vmax) determined in the same microsomal preparations yielded 30.2+/-5.0 and 32.3+/-3.9 pmol (mg protein)(-1) min(-1) in rat liver and 55.3+/-5.7 and 65.2+/-4.3 pmol (mg protein)(-1) min(-1) in human liver microsomes. Phase II conjugation of the carveol isomers by rat and human liver microsomes in the presence of UDPGA (uridine S'-diphosphogluaronic acid) only revealed glucuronidation of 4R, 6S-(-)-carveol. Vmax for glucuronide formation was more than 4-fold higher in the rat liver compared with human liver preparations (185.9+/-34.5 and 42.6+/-7.1 pmol (mg protein)(-1) min(-1), respectively). Km values, however, showed no species-related difference (13.9+/-4.1 microM and 10.2+/-2.2 microM). This study demonstrated stereoselectivity in phase-I and phase-II metabolism for R-(-)- and S-(+)-carvone and might be predictive for carvone biotransformation in man.

Antimicrobial study of essential oils of Ocimum gratissimum leaves and Zanthoxylum xanthoxyloides fruits from Cameroon.

An investigation of antimicrobial activities of essential oils of fresh leaves of Ocimum gratissimum and the essential oil of the dried fruits of Zanthoxylum xanthoxyloides was carried out. The essential oils showed extensive inhibition zones and are, therefore, effective antimicrobial systems.

Aromatherapy: evidence for sedative effects of the essential oil of lavender after inhalation.

The sedative properties of the essential oil of Lavender (Lavandula angustifolia Miller) and of its main constituents--linalool and linalyl acetate--were investigated in mice followed up in a series of experimental procedures. The significant decrease in the motility of female and male laboratory animals under standardized experimental conditions is found to be closely dependent on the exposure time to the drugs. Nevertheless after an injection of caffeine into mice a hyperactivity was observed which was reduced to nearly a normal motility only by inhalation of these fragrance drugs. In particular the correlation of the motility of the animals to linalool in serum is experimentally proven, thus furnishing evidence of the aromatherapeutical use of herbal pillows employed in folk medicine since ancient times in order to facilitate falling asleep or to minimize stressful situations of man.

[Norbornane compounds in pharmaceutical research]. / Norbornanverbindungen in der pharmazeutischen Forschung.

This review compiles the literature about norbornanes which already are used as medicaments and such bicyclo [2.2.1]heptanes, which are connected with drug research in some way. As is shown for the period from 1967 until 1980 the occupation with these bicyclic compounds has gained some importance in drug research, not only because they are used medicinally but also because they are used as suitable test molecules for studying structure-activity-relationships by reason of their special molecular shape, their voluminous, bicyclic carbon skeleton and the sterically fixed position of their substituents.

Investigation of cytotoxic effects of 8 norbornane derivatives on 4 human cancer cell lines using the MTT assay.

A group of 8 structurally modified norbornane analogs, selected on basis of water solubility, was tested for its potential cytotoxic effects using a modified MTT assay. Four tumor cell lines, three hematological and a hepatocellular one were used as an experimental model system. Some analogs exhibited an antitumor effect which was shown to be tissue specific. The cytotoxic effect is most likely due to the nature of the side chains rather than to the basic bicyclic norbornane structure of the molecule. These results not only provide a basis for the synthesis of derivatives with effective antitumor activity, but also give some indication of the the molecular target of these compounds.

[Effects of valerian root oil, borneol, isoborneol, bornyl acetate and isobornyl acetate on the motility of laboratory animals (mice) after inhalation]. / Wirkungen von Baldrianöl, Borneol, Isoborneol, Bornylacetat und Isobornylacetat auf die Motilität von Versuchstieren (Mäusen) nach Inhalation.

The aromatherapeutical use of commercial valerian root oil (Chinese origin) and of pure fragrance compounds--borneol, isoborneol, bornyl acetate (main constituent of the proved valerian root oil) and isobornyl acetate--as potentially drugs with sedative effects after inhalation was investigated in an animal experiment (mice). In additional analyses the mice were treated i.p. by caffeine and distinct sedative effects were observed only by inhalation of the cited substances.

[Structure-activity relationship of isocamphane derivatives/Two examples (author's transl)]. / Struktur-Wirkungs-Beziehung von Isocamphan-Derivaten. 2 Beispiele.

In a short review the dependence of the activity of isocamphane derivatives on their chemical structure is shown by means of two examples. In the first example--that of drug research--the choleretic activity of Felogen analogues is discussed. In the second example the dependence of the camphoraceous odour on the molecular shape in accordance with Amoore's stereochemical theory of odour and the influence of a certain osmophoric group on the nuance of a fragrance is shown.

[Phytopharmacological study on proadiphene, amiphenazole and bemegride in association with phenobarbitone (author's transl)]. / Die phytopharmakologische Untersuchung von Proadifen, Amiphenazol und Bemegrid in Kombination mit Phenobarbital

The capacity of 2-diethylaminoethyl-alpha, alpha-diphenylvalerate (proadiphene), 2,4-diamino-5-phenyl-thiazole (amiphenazole) and 2,6-dioxo-4-methyl-4-ethyl-piperidine (bemegride) of stimulating or stopping the growth of seedlings of Lepidium sativum L. was tested. Only bemegride shows a weak stimulating effect between 10(-3) and 10(-2) moles/l. In combination with phenobarbital these compounds counteract the stimulating effect and increase the inhibiting one of this barbiturate on the growth of the seedlings.

[The effects of barbiturates on the embryonic growth of seedling of lepidium sativum L (author's transl)]. / Die Einwirkung von Barbituraten auf das embryonale Waschstum von Kressekeimlingen (Lepidium sativum L)

The influence of some important barbiturates on the capacity to stimulate or to stop the growth of seedling of Lepidium sativum L. was tested and the results statistically evaluated. Phenobarbital, cyclobarbital and pentobarbitial show a significant stimulating effect on growth between 10(-2) and 10(-4) moles/l. All barbiturates in concentrations over 10(-3)M act strongly inhibiting. The average inhibitory concentrations (ID50) show a clear dependence on biological properties, in the first place the partition coefficient.

Evaluation of the harmonizing effect of ylang-ylang oil on humans after inhalation.

Scientific evaluations of the effects of fragrances on humans are rather scarce. The aim of this investigation was to study the effects of ylang-ylang oil (Cananga odorata, Annonaceae) on hu-man physiological parameters and self-evaluation. Twenty-four healthy volunteers participated in the experiments. Fragrances were administered by inhalation. Physiological parameters recorded were skin temperature, pulse rate, breathing rate and blood pressure. Self-evaluation was assessed in terms of alertness, attentiveness, calmness, mood, relaxation and vigor. Additionally, fragrances were rated in terms of pleasantness, intensity and effect. The present investigation showed that ylang-ylang oil may be characterized by the concept of "harmonization" rather than relaxation/sedation. Compared to an odorless placebo, ylang-ylang oil caused significant decreases in blood pressure and pulse rate as well as significant increases of subjective attentiveness and alertness. Correlational analyses revealed that the observed effects are mainly due to a subjective odor experience.

Surface comparisons of some odour molecules: conformational calculations on sandalwood odour V.

Molecular surface comparison seems to be a very suitable tool for the investigation of small differences between biologically active and inactive compounds of the same structural type. A fast method for such comparisons, based on volume matching followed by the estimation of comparable surface dots, is presented and applied on a few selected sandalwood odour molecules.