Fragrance contact dermatitis in Korea: a joint study

The purpose of this study is to determine the frequency of responses to selected fragrances in patients with suspected fragrance allergy and to evaluate the risk factors. 9 dermatology departments of university hospitals have participated in this study for the past 1 year. To determine allergic response to fragrances, 18 additional fragrances in addition to the Korean standard and a commercial fragrance series were patch-tested in patients with suspecting cosmetic contact dermatitis. Over 80% of the patients were women, and the most common site was the face. Cinnamic alcohol and sandalwood oil (Santalum album L.) showed high frequencies of positive responses. Of the specific fragrances, ebanol, alpha-isomethyl-ionone (methyl ionone-gamma) and Lyral (hydroxyisohexyl 3-cyclohexane carboxdaldehyde) showed high positive responses. We compared the results obtained during this study with those of other studies and concluded that including additional fragrance allergens may be useful for the detection of fragrance allergy.

Synthesis, characterization and biological activity of oxovanadium (IV) complexes with cyclic polyalcohols

Oxovanadium (IV) complexes of the cyclic polyols conduritol C (cond) and myo-inositol (inos) of stoichiometry Na(2)[VO(cond)(2)].2H(2)O and Na(2)[VO(inos)(2)].H(2)O were obtained in aqueous alkaline solutions. They were characterized by infrared and UV-Vis spectroscopies, thermoanalytical (thermogravimetric and differential thermal analysis) data and magnetic susceptibility measurements. The biological activities of the complexes on the proliferation, differentiation and glucose consumption were tested on osteoblast-like cells in culture. Conduritol C and myo-inositol did not produce any effect on these parameters. Normal and tumoral cell proliferation was inhibited about (ca.40-60%) by the two oxovanadium (IV) complexes in concentrations as low as 100microM. The complexes were also inhibitory on cell differentiation (ca. 70-80%) while they stimulate glucose consumption. Comparisons of these effects with those of the oxovanadium (IV) cation, under the same experimental conditions, were also performed.

Neuroprotection From Soman-induced Seizures In The Rodent: Evaluation With Diffusion- And T2-weighted Magnetic Resonance Imaging

Exposure to the organophosphate nerve agent soman produces seizures that in turn lead to neuropathology. This study describes the temporal and spatial evolution of brain pathology following soman-induced convulsions and the attenuation of these alterations after neuroprotective intervention with magnetic resonance imaging (MRI). Neuroimaging 12 h after soman exposure, the hippocampus and thalamus exhibited significant decreases (23%) in apparent diffusion coefficients (ADC). These acute effects were resolved by 7 days. In addition, T2 measurements declined significantly at 12 h (37%) returning to near normal values by 24 h. Histopathological analyses confirmed moderate cell loss within the hippocampus and piriform cortex. Together these findings suggest that initial cell death was resolved through regional cellular remodeling. Pharmacological countermeasures were administered in the form of diazepam, a benzodiazepine anticonvulsant, or gacyclidine (GK-11), an anti-glutamatergic compound. Diazepam therapy applied immediately after soman exposure prevented acute ADC changes. However the presence of edema, using T2 measurements, was detected at 3 h within the retrosplenial, amygdala and piriform cortices and at 12 h in the thalamus (34% below normal). GK-11 therapy appeared to prevent most of these changes. However at 7 days after soman, a decrease (17%) in ADC was observed in the piriform cortex. Pathology was confined to the piriform cortex suggesting that this region is more difficult to protect. This is the first report that provides temporal and spatial resolution using MRI with histological correlation of pharmacological interventions against soman-mediated seizure-induced neuropathology.

Antioxidant and Antimycobacterial Activities ofTabernaemontana catharinensisExtracts Obtained by Supercritical CO2+ Cosolvent

In the present work the antioxidant and antimycobacterial activities were determined for extracts from Tabernaemontana catharinensis. The extracts' global yields were obtained using supercritical CO2 plus cosolvent. The cosolvents ethanol, isopropyl alcohol, methanol, and water and their mixtures were used. The extracts were fractionated and analyzed by thin-layer chromatography and gas chromatography/flame ionization detection. The antimycobacterial activity was measured against Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium kansasii. The antioxidant activity was determined by the coupled reaction of beta-carotene and limonene acid. The average global yield was approximately constant (2.4 +/- 0.1%) for the alcoholic cosolvents and significantly larger (15 +/- 1%) for the cosolvent water and its alcoholic mixtures. The content of alkaloids in the extracts was strongly affected by the cosolvent. The antioxidant activity of the extracts ranged from 53% to 95%. The highest antimycobacterial activity was detected in the alkaloidal fraction (minimum inhibitory concentration = 128 microg/mL), while the lowest was verified in the aqueous fraction (minimum inhibitory concentration >512 microg/mL).

Anticonvulsant evaluation of safranal and crocin from Crocus sativus in mice

The anticonvulsant activities of Crocus sativus stigma constituents, safranal and crocin, were evaluated in mice using pentylenetetrazole (PTZ)-induced convulsions in mice. Safranal (0.15 and 0.35 ml/kg, i.p.) reduced the seizure duration, delayed the onset of tonic convulsions and protected mice from death. Crocin (200 mg/kg, i.p.) did not show anticonvulsant activity.

Characterization of cyclicity and hormonal profile with impending ovarian failure in a novel chemical-induced mouse model of perimenopause

4-Vinylcyclohexene diepoxide (VCD) causes early, gradual ovarian failure in mice because it specifically targets small pre-antral ovarian follicles. The period between loss of these follicles and ovarian failure is analogous to perimenopause in women. We sought to characterize the period of onset of ovarian failure in VCD-treated mice in regard to estrous cycle length and hormonal changes. Female C57Bl/6 mice (age, 28 days) were dosed daily for 15 days with VCD (160 mg/kg intraperitoneally) to cause early ovarian failure or with vehicle only (control animals). Cycle length was monitored by vaginal cytology. Plasma levels of 17beta-estradiol (E2), progesterone (P4), and follicle-stimulating hormone (FSH) in control and VCD-treated animals were measured during proestrus of cycles 1 through 12. Cycle length (mean, 5.8 days) did not differ between groups for cycles 1 through 4. In contrast, cycle length during cycles 5 through 12 was increased (mean length, 10.9 days; P < 0.05 versus control) in VCD-treated animals, which also showed an apparent increase in plasma FSH levels. Plasma E2 and P4 at proestrus did not differ between groups during any cycle. Ovarian failure in VCD-treated mice was confirmed by histological evaluation on day 156 after onset of dosing, whereas control animals were still cycling. Therefore, despite compromised cycle length in VCD-treated mice, peak ovarian steroid production in preovulatory follicles at proestrus is adequate. These results demonstrate that the VCD-treated mouse can serve as an appropriate model to mimic hormonal changes during the perimenopausal transition in women.

Hydrodistillation-headspace solvent microextraction, a new method for analysis of the essential oil components of Lavandula angustifolia Mill

A new method involving concurrent headspace solvent microextraction combined with continuous hydrodistillation (HD-HSME) for the extraction and pre-concentration of the essential oil of Lavandula angustifolia Mill. into a microdrop is developed. A microdrop of n-hexadecane containing n-heptadecane (as internal standard) extruded from the needle tip of a gas chromatographic syringe was inserted into the headspace above the plant sample. After extraction for an optimized time, the microdrop was retracted into the syringe and injected directly into a GC injection port. The effects of the type of extracting solvent, sample mass, microdrop volume and extraction time on HD-HSME efficiency were investigated and optimized. Using this method, thirty-six compounds were extracted and identified. Linalool (32.8%), linalyl acetate (17.6%), lavandulyl acetate (15.9%), alpha-terpineol (6.7%) and geranyl acetate (5.0%) were found to be the major constituents. To the best of our knowledge this is the first report on the use of continuous headspace solvent microextraction coupled with hydrodistillation for investigation of essential oil components.

Radical scavenging activity of Crocus sativus L. extract and its bioactive constituents

Radical scavenging activity is involved in aging processes, antiinflammatory, anticancer and wound healing activity. Hence, in the present study the DPPH radical scavenging activity of a natural product that possesses biological properties, an extract of Crocus sativus L. (saffron), grown in Crocos, Kozani (Greece), and some of its bioactive constituents (crocin, safranal) was studied. It was shown that a methanol extract of Crocus sativus exhibited high antioxidant activity, although it contains several active and inactive constituents. In trying to approximate a structure-activity relationship, two bioactive constituents of saffron extract were tested, namely crocin and safranal. Crocin showed high radical scavenging activity (50% and 65% for 500 and 1,000 ppm solution in methanol, respectively), followed by safranal (34% for 500 ppm solution). All the tested samples showed high radical scavenging activity, probably due to the ability to donate a hydrogen atom to the DPPH radical.Thus, saffron grown in Greece can be used promisingly in functional foods, drinks with antioxidant activity, in pharmaceutical and cosmetic preparations for their antioxidant activity and probably for their antiaging activity. Saffron can also be used internally in the form of powder or other pharmacotechnical formulae as a food supplement with antioxidant properties.

Trial-by-trial discrimination of three enantiomer pairs by neural ensembles in mammalian olfactory bulb

Populations of output neurons in the mammalian olfactory bulb (OB) exhibit distinct, widespread spatial and temporal activation patterns when stimulated with odorants. However, questions remain as to how ensembles of mitral/tufted (M/T) neurons in the mammalian OB represent odorant information. In this report, the single-trial encoding limits of random ensembles of putative single- and multiunit M/T cells in the anesthetized rat OB during presentations of enantiomers of limonene, carvone, and 2-butanol are investigated using simultaneous multielectrode recording techniques. The results of these experiments are: the individual constituents of our recorded ensembles broadly represent information about the presented odorants, the ensemble single-trial response of small spatially distributed populations of M/T neurons can readily discriminate between six different odorants, and the most consistent odorant discrimination is attained when the ensemble consists of all available units and their responses are integrated over an entire breathing cycle. These results suggest that small differences in spike counts among the ensemble members become significant when taken within the context of the entire ensemble. This may explain how ensembles of broadly tuned OB neurons contribute to olfactory perception and may explain how small numbers of individual units receiving input from distinct olfactory receptor neurons can be combined to form a robust representation of odorants.

Influence of carrot psyllid (Trioza apicalis) feeding or exogenous limonene or methyl jasmonate treatment on composition of carrot (Daucus carota) leaf essential oil and headspace volatiles

The effect of carrot psyllid (Trioza apicalis Förster) feeding and limonene and methyl jasmonate (MeJA) treatments on the essential oil composition and headspace volatiles of carrot (Daucus carota ssp. sativus), cvs. Parano and Splendid, leaves was studied. Carrot psyllid feeding significantly increased the concentrations of sabinene, beta-pinene, and limonene, whereas limonene treatment increased the concentration of (Z)-beta-ocimene in the leaves of both cultivars. The limonene treatment significantly increased the concentration of total phenolics in the leaves of both cultivars, and MeJA treatment increased phenolic concentration in the leaves of Parano. Exogenous limonene spray did not decrease the number of carrot psyllid eggs laid either 2 or 24 h after treatment. The results suggest that carrot psyllid feeding induces changes in the endogenous monoterpene pool in the carrot leaves. Limonene and MeJA treatments affect some induced defenses of the carrot, but the exogenous limonene spray is not an effective oviposition deterrent against carrot psyllid.

Maturation of odor representation in the honeybee antennal lobe

The antennal lobe (AL) is the first center for processing odors in the insect brain, as is the olfactory bulb (OB) in vertebrates. Both the AL and the OB have a characteristic glomerular structure; odors sensed by olfactory receptor neurons are represented by patterns of glomerular activity. Little is known about when and how an odor begins to be perceived in a developing brain. We address this question by using calcium imaging to monitor odor-evoked neural activity in the ALs of bees of different ages. We find that odor-evoked neural activity already occurs in the ALs of bees as young as 1 or 2 days. In young bees, the responses to odors are relatively weak and restricted to a small number of glomeruli. However, different odors already evoke responses in different combinations of glomeruli. In mature bees, the responses are stronger and are evident in more glomeruli, but continue to have distinct odor-dependent signatures. Our findings indicate that the specific glomerular patterns for odors are conserved during the development, and that odor representations are fully developed in the AL during the first 2 weeks following emergence.

Patch testing with a new fragrance mix detects additional patients sensitive to perfumes and missed by the current fragrance mix

The currently used 8% fragrance mix (FM I) does not identify all patients with a positive history of adverse reactions to fragrances. A new FM II with 6 frequently used chemicals was evaluated in 1701 consecutive patients patch tested in 6 dermatological centres in Europe. FM II was tested in 3 concentrations - 28% FM II contained 5% hydroxyisohexyl 3-cyclohexene carboxaldehyde (Lyral), 2% citral, 5% farnesol, 5% coumarin, 1% citronellol and 10%alpha-hexyl-cinnamic aldehyde; in 14% FM II, the single constituents' concentration was lowered to 50% and in 2.8% FM II to 10%. Each patient was classified regarding a history of adverse reactions to fragrances: certain, probable, questionable, none. Positive reactions to FM I occurred in 6.5% of the patients. Positive reactions to FM II were dose-dependent and increased from 1.3% (2.8% FM II), through 2.9% (14% FM II) to 4.1% (28% FM II). Reactions classified as doubtful or irritant varied considerably between the 6 centres, with a mean value of 7.2% for FM I and means ranging from 1.8% to 10.6% for FM II. 8.7% of the tested patients had a certain fragrance history. Of these, 25.2% were positive to FM I; reactivity to FM II was again dose-dependent and ranged from 8.1% to 17.6% in this subgroup. Comparing 2 groups of history - certain and none - values for sensitivity and specificity were calculated: sensitivity: FM I, 25.2%; 2.8% FM II, 8.1%; 14% FM II, 13.5%; 28% FM II, 17.6%; specificity: FM I, 96.5%; 2.8% FM II, 99.5%; 14% FM II, 98.8%; 28% FM II, 98.1%. 31/70 patients (44.3%) positive to 28% FM II were negative to FM I, with 14% FM II this proportion being 16/50 (32%). In the group of patients with a certain history, a total of 7 patients were found reacting to FM II only. Conversely, in the group of patients without any fragrance history, there were significantly more positive reactions to FM I than to any concentration of FM II. In conclusion, the new FM II detects additional patients sensitive to fragrances missed by FM I; the number of false-positive reactions is lower with FM II than with FM I. Considering sensitivity, specificity and the frequency of doubtful reactions, the medium concentration, 14% FM II, seems to be the most appropriate diagnostic screening tool.

Chemical defense in harvestmen (arachnida, opiliones): do benzoquinone secretions deter invertebrate and vertebrate predators?

Two alkylated 1,4-benzoquinones were identified from the defensive secretion produced by the neotropical harvestman Goniosoma longipes (Gonyleptidae). They were characterized as 2,3-dimethyl-1,4-benzoquinone and 2-ethyl-3-methyl-1,4-benzoquinone. We tested the effectiveness of these benzoquinone secretions against several predator types, including invertebrates and vertebrates. Different predators were exposed to the harvestmen's gland secretion or to distilled water in laboratory bioassays. Our results indicate that secretions containing the 1,4-benzoquinones released by G. longipes can be an effective defense against predation, and that the effectiveness of the secretion is dependent on the predator type. The scent gland secretion repelled seven ant species, two species of large wandering spiders, and one frog species, but was not an effective defense against an opossum. Our study also demonstrates that the scent gland secretion of G. longipes can work as a chemical shield preventing the approach of three large predatory ants for at least 10 min. The chemical shield may protect the harvestman against successive attacks of the same ant worker and also allow the harvestman to flee before massive ant recruitment. Our data support the suggestion that chemical defenses may increase survival with some but not all potential predators. This variation in defense effectiveness may result from many interacting factors, including the attack strategy, size, learning ability, and physiology of the predators, as well as the chemical nature of the defensive compounds, type of emission, and amount of effluent released by the prey.

In vivo Evaluation of Limonene-Based Transdermal Therapeutic System of Nicorandil in Healthy Human Volunteers

Hydroxypropyl methylcellulose (HPMC) gel drug reservoir system prepared with 70:30 v/v ethanol-water solvent system containing 6% w/w of limonene was effective in promoting the in vitro transdermal delivery of nicorandil. The objective of the present study was to fabricate and evaluate a limonene-based transdermal therapeutic system (TTS) for its ability to provide the desired steady-state plasma concentration of nicorandil in human volunteers. The in vitro permeation of nicorandil from a limonene-based HPMC gel drug reservoir was studied across excised rat skin (control), EVA2825 membrane, adhesive-coated EVA2825 membrane and adhesive-coated EVA2825 membrane-excised rat skin composite to account for their effect on the desired flux of nicorandil. The flux of nicorandil from the limonene-based HMPC drug reservoir across EVA2825 membrane decreased to 215.8 +/- 9.7 microg/cm(2).h when compared to that obtained from control, indicating that EVA2825 was effective as a rate-controlling membrane. The further decrease in nicorandil flux across adhesive-coated EVA2825 membrane and adhesive-coated EVA2825 membrane-excised rat skin composite showed that the adhesive coat and skin also controlled the in vitro transdermal delivery. The limonene-based drug reservoir was sandwiched between adhesive-coated EVA2825-release liner composite and a backing membrane. The resultant sandwich was heat-sealed as circle-shaped patch (20 cm(2)), trimmed and subjected to in vivo evaluation in human volunteers against immediate-release tablets of nicorandil (reference formulation). The fabricated limonene-based TTS of nicorandil provided a steady-state plasma concentration of 21.3 ng/ml up to 24 h in healthy human volunteers. It was concluded that the limonene-based TTS of nicorandil provided the desired plasma concentration of the drug for the predetermined period of time with minimal fluctuations and improved bioavailability.

Regio- and stereoselective fungal oxyfunctionalisation of limonenes

Selective transformations of limonene by asco- and basidiomycetes were investigated. On the shake flask scale, Penicillium citrinum hydrated R-(+)-limonene to a-terpineol [83% regioselectivity (rs), more than 80 mg l(-1) product yield], and Gongronella butleri catalysed the terminal oxidation to yield perillyl alcohol (60% rs, 16 mg l(-1)). On the laboratory bioreactor scale, Penicillium digitatum produced a peak concentration of 506 mg a-terpineol l(-1) in the fed-batch mode, equivalent to a theoretical yield of 67%, and no volatile by-products were found. Fusarium proliferatum transformed R-(+)-limonene enantiospecifically to cis-(+)-carveol (98.6% ee, more than 35 mg l(-1) product yield) and S-(-)-limonene predominantly to trans-(-)-carveol (96.3% ee). Pleurotus sapidus selectively dehydrogenised the accumulating trans-(-)-carveol to the corresponding enantiopure R-(-)-carvone. The results show that a careful selection of strain and bioprocess parameters may improve both the yield and the optical purity of a desired product.

Isochorismate Pyruvate Lyase: A Pericyclic Reaction Mechanism?

Isochorismate pyruvate lyase (IPL) catalyzes the cleavage of isochorismate to give salicylate and pyruvate, a key step in bacterial siderophore biosynthesis. We investigated the enzyme from Pseudomonas aeruginosa using isochorismate selectively deuterated at C2 as a substrate. Monitoring the reaction by 2H NMR spectroscopy revealed that the label is quantitatively transferred from C2 to C9, producing stoichiometric amounts of [3-2H]pyruvate as product. Moreover, the deuterium kinetic isotope effect of 2.34 +/- 0.08 on kcat indicates that C-H cleavage is significantly rate limiting. Consistent with these data, hybrid density functional theory (HDFT) calculations at the Becke3LYP/DZ+(2d,p) level of theory predict a concerted but highly asynchronous pericyclic transition structure, in which carbon-oxygen bond cleavage is more advanced than hydrogen atom transfer from C2 to C9; the calculated 2H isotope effect of 2.22 at C2 is in excellent accord with the experimental value. Together, these findings indicate that IPL should be added to the small set of proteins that are known to catalyze pericyclic reactions. They also raise the possibility that enzymes, such as chorismate pyruvate lyase, salicylate synthase, 4-amino-4-deoxychorismate lyase, and anthranilate synthase, which accelerate formally similar reaction steps, may also exploit pericyclic mechanisms.

Chemical composition and antibacterial activity of the essential oil and the gum of Pistacia lentiscus Var. chia

The essential oil and gum of Pistacia lentiscus var. chia, commonly known as the mastic tree, are natural antimicrobial agents that have found extensive uses in medicine in recent years. In this work, the chemical composition of mastic oil and gum was studied by GC-MS, and the majority of their components was identified. alpha-Pinene, beta-myrcene, beta-pinene, limonene, and beta-caryophyllene were found to be the major components. The antibacterial activity of 12 components of mastic oil and the oil itself was evaluated using the disk diffusion method. Furthermore, attempts were made to separate the essential oil into different fractions in order to have a better picture of the components responsible for its antibacterial activity. Several trace components that appear to contribute significantly to the antibacterial activity of mastic oil have been identified: verbenone, alpha-terpineol, and linalool. The sensitivity to these compounds was different for different bacteria tested (Escherichia coli, Staphylococcus aureus, and Bacillus subtilis), which suggests that the antibacterial efficacy of mastic oil is due to a number of its components working synergistically. The establishment of a correlation between the antibacterial activity of mastic oil and its components was the main purpose of this research. Mastic gum was also examined, but it proved to be more difficult to handle compared to the essential oil.

Evolution of functional cyclohexadiene-based synthetic reagents: the importance of becoming aromatic

Suites of new precursors designed around a cyclohexadiene core and intended to mediate "clean" radical chain syntheses have been prepared and tested. 1-Functionalized cyclohexa-2,5-dienes were found to readily donate H-atoms, and the resulting cyclohexadienyl radicals rapidly extruded their functional group as a free radical, because this beta-scission restored aromaticity to the ring. This concept was employed to generate designer radicals from esters of the corresponding alcohols with 1-methyl- or 1-phenylcyclohexa-2,5-diene-1-carboxylic acids. In a similar way, pre-adapted carbamoyl radicals were obtained from cyclohexadienyl-amides and proved advantageous for syntheses of alpha- and beta-lactams. Oxime ether substituted carbamoyl radicals cyclized successfully in convenient syntheses of dihydroindolin-2-ones with N-functionality at the 3-position. Similarly, silicon-centered radicals were obtained from 1-silylated cyclohexadienes, and these reagents proved to be very efficient, environmentally benign organotin hydride substitutes. Radical reactions including reductions, cyclizations, intermolecular additions, and hydrosilylations were carried out in high yields with this reagent. Other heteroatom-centered radicals, especially N-centered radicals, were obtained from appropriate cyclohexadienes enabling chain hydroaminations to be conducted. Several of the cyclohexadiene precursors proved to be useful for electron paramagnetic resonance (EPR) spectroscopic purposes, and this enabled rate constants for fragmentations of the cyclohexadienyl radicals to be obtained. Kinetic data for H-atom abstraction from cyclohexadienes, the second propagation step of the chain processes, was derived from customized radical clocks and from EPR measurements. In this way, conceptual tools were developed for improving future synthetic methodology based around these reagents.

Photosensitized Conversion of 9,10-Deoxytridachione to Photodeoxytridachione

[reaction: see text] The photochemical conversion of 9,10-deoxytridachione to photodeoxytridachione has been photosensitized. The conversion was also quenched by piperylene. Photodeoxytridachione was produced in good yields under conditions in which only the cyclohexadiene group is sensitized. The results show that some, and perhaps all, of the photoreactions of 9,10-deoxytridachione occur through a triplet excited state. The mechanistic and biosynthetic implications of these results are discussed.

Quantitative analysis of valienamine in the microbial degradation of validamycin A after derivatization with p-nitrofluorobenzene by reversed-phase high-performance liquid chromatography

A reversed-phase high-performance liquid chromatography method for the quantitative analysis of valienamine in the microbial degradation of validamycin A, using a procedure for pre-column derivatization of valienamine with p-nitrofluorobenzene is described. Valienamine in the broth was first isolated with the ion-exchange method. The optimized conditions for the derivatization were the reaction time 30 min and reaction temperature 100 degrees C. With the mobile phases consisting of acetonitrile-water (12:88) (eluent A) and methanol (eluent B), the gradient was carried out with 100% of A for 15 min and then 100% of B for another 10 min. The parameters in the process were the flow rate of the mobile phase 1.0 ml/min, the injection volume 20 microl, the column temperature 40 degrees C and wavelength of ultraviolet detection 398 nm in all runs. A good linearity was found in the range of 0.5-150.0 microg/ml. Both intra- and inter-day precisions of valienamine, expressed as the relative standard deviation, were less than 9.4%. Accuracy, expressed as the relative error, range from -0.5 to 2.7%. The mean absolute recovery of valienamine at three different concentrations was 94.2%. The method was proved suitable for the study on the process of microbial degradation of validamycin A to produce valienamine.

Flavor encapsulation in yeasts: limonene used as a model system for characterization of the release mechanism

Empty yeast cells are used as a new delivery system for flavor encapsulation. The flavor release mechanism from yeast cells is characterized using a series of analytical techniques, and limonene is used as a model representing a hydrophobic flavor. Furthermore, the thermal stability of the capsules was assessed. The characterization of the cell wall structure gives rise to the development of an empirical model explaining water adsorption as well as the desorption singularities observed on drying. The study of the rate of flavor release as a function of temperature and water uptake in the cell wall clearly demonstrated a particular behavior of the yeast cell wall permeability. Below a water activity around 0.7, no flavor release is permitted whereas release occurs above it. Surface analysis on dry or wet cells using atomic force microscopy is discussed.

Role of the Cocatalyst in the Copolymerization of CO2 and Cyclohexene Oxide Utilizing Chromium Salen Complexes

The mechanism of the copolymerization of cyclohexene oxide and carbon dioxide to afford poly(cyclohexylene)carbonate catalyzed by (salen)CrN3 (H2salen = N,N,'-bis(3,5-di-tert-butylsalicylidene)-1,2-ethylene-diimine) in the presence of a broad range of cocatalysts has been studied. We have previously established the rate of copolymer formation to be very sensitive to both the electron-donating ability of the salen ligand and the [cocatalyst], where N-heterocyclic amines, phosphines, and ionic salts were effective cocatalysts. Significant increases in the rate of copolymerization have been achieved with turnover frequencies of approximately 1200 h(-1), thereby making these catalyst systems some of the most active and robust thus far uncovered. Herein we offer a detailed explanation of the role of the cocatalyst in the copolymerization of CO2 and cyclohexene oxide catalyzed by chromium salen derivatives. A salient feature of the N-heterocyclic amine- or phosphine-cocatalyzed processes is the presence of an initiation period prior to reaching the maximum rate of copolymerization. Importantly, this is not observed for comparable processes involving ionic salts as cocatalysts, e.g., PPN+ X-. In these latter cases the copolymerization reaction exhibits ideal kinetic behavior and is proposed to proceed via a reaction pathway involving anionic six-coordinate (salen)Cr(N3)X- derivatives. By way of infrared and 31P NMR spectroscopic studies, coupled with in situ kinetic monitoring of the reactions, a mechanism of copolymerization is proposed where the neutral cocatalysts react with CO2 and/or epoxide to produce inner salts or zwitterions which behave in a manner similar to that of ionic salts.

An Experimental and Molecular-Modeling Study of the Binding of Linked Sulfated Tetracyclitols to FGF-1 and FGF-2

The experimental binding affinities of a series of linked sulfated tetracyclitols [Cyc2N-R-NCyc2, where Cyc = C6H6(OSO3Na)3 and R = (CH2)n (n = 2-10), p-xylyl or (C2H4)2-Ncyc] for the fibroblast growth factors FGF-1 and FGF-2 have been measured by using a surface plasmon resonance assay. The KD values range from 7.0 nM to 1.1 microM for the alkyl-linked ligands. The binding affinity is independent of the flexibility of the linker, as replacement of the alkyl linker with a rigid p-xylyl group did not affect the KD. Calculations suggest that binding modes for the p-xylyl-linked ligand are similar to those calculated for the flexible alkyl-linked tetracyclitols. The possible formation of cross-linked FGF:cyclitol complexes was examined by determining KD values at increasing protein concentrations. No changes in KD were observed; this suggesting that only 1:1 complexes are formed under these assay conditions. Monte Carlo multiple-minima calculations of low-energy conformers of the FGF-bound ligands showed that all of the sulfated tetracyclitol ligands can bind effectively in the heparan sulfate-binding sites of FGF-1 and FGF-2. Binding affinities of these complexes were estimated by the Linear Interaction Energy (LIE) method to within a root-mean-square deviation of 1 kcal mol(-1) of the observed values. The effect of incorporating cations to balance the overall charge of the complexes during the LIE calculations was also explored.

Gas-phase chemistry of (alpha-terpineol with ozone and OH radical: rate constants and products

A bimolecular rate constant, kOH+alpha-terpineol, of (1.9 +/- 0.5) x 10(-10) cm3 molecule(-1) s(-1) was measured using gas chromatography/mass spectrometry and the relative rate technique for the reaction of the hydroxyl radical (OH) with alpha-terpineol (1-methyl-4-isopropyl-1-cyclohexen-8-ol) at (297 +/- 3) K and 1 atm total pressure. Additionally, a bimolecular rate constant, kO3+alpha-terpineol, of (3.0 +/- 0.2) x 10(-16) cm3 molecule(-1) s(-1) was measured by monitoring the first order decrease in ozone concentration as a function of excess alpha-terpineol. To better understand alpha-terpineol's gas-phase transformation in the indoor environment, the products of the alpha-terpineol + OH and alpha-terpineol + 03 reactions were also investigated. The positively identified alpha-terpineol/OH reaction products were acetone, ethanedial (glyoxal, HC(=O)C(=O)H), and 2-oxopropanal (methyl glyoxal, CH3C(=O)C(=O)H). The positively identified alpha-terpineol/O3 reaction product was 2-oxopropanal (methyl glyoxal, CH3C(=O)C(=O)H). The use of derivatizing agents O-(2,3,4,5,6-pentalfluorobenzyl)hydroxylamine (PFBHA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) clearly indicated that several other reaction products were formed. The elucidation of these other reaction products was facilitated by mass spectrometry of the derivatized reaction products coupled with plausible alpha-terpineol/OH and alpha-terpineol/O3 reaction mechanisms based on previously published volatile organic compound/ OH and volatile organic compound/O3 gas-phase reaction mechanisms.

Effect of Different Locations on the Chemical Composition of Essential Oils of Laurel (Laurus nobilis L.) Leaves Growing Wild in Turkey

The essential oil components of Laurus nobilis gathered from seven different locations of Turkey were identified by gas chromatography/mass spectrometry. The oil yields on a dry weight basis ranged between 1.4% to 2.6%. The major component was 1,8-cineole (51.73-68.48%); other predominant components were alpha-terpinyl acetate (4.04-9.87%), sabinene (4.44-7.75%), alpha-pinene (2.93-4.89%), beta-pinene (2.58-3.91%), terpinene-4-ol (1.33-3.24%), and alpha-terpineol (0.95-3.05%). Minor qualitative and major quantitative variations of some compounds were determined with respect to localities of collection. As a result, the 1,8-cineole content of these oils was significantly higher than those of other constituents of L. nobilis. Laurel is usually considered as the natural source of this compound, used in the flavor and fragrance industry.

The capacity for thermal protection of photosynthetic electron transport varies for different monoterpenes in Quercus ilex

Heat stress resistance of foliar photosynthetic apparatus was investigated in the Mediterranean monoterpene-emitting evergreen sclerophyll species Quercus ilex. Leaf feeding with fosmidomycin, which is a specific inhibitor of the chloroplastic isoprenoid synthesis pathway, essentially stopped monoterpene emission and resulted in the decrease of the optimum temperature of photosynthetic electron transport from approximately 38 degrees C to approximately 30 degrees C. The heat stress resistance was partly restored by fumigation with 4 to 5 nmol mol(-1) air concentrations of monoterpene alpha-pinene but not with fumigations with monoterpene alcohol alpha-terpineol. Analyses of monoterpene physicochemical characteristics demonstrated that alpha-pinene was primarily distributed to leaf gas and lipid phases, while alpha-terpineol was primarily distributed to leaf aqueous phase. Thus, for a common monoterpene uptake rate, alpha-terpineol is less efficient in stabilizing membrane liquid-crystalline structure and as an antioxidant in plant membranes. Furthermore, alpha-terpineol uptake rate (U) strongly decreased with increasing temperature, while the uptake rates of alpha-pinene increased with increasing temperature, providing a further explanation of the lower efficiency of thermal protection by alpha-terpineol. The temperature-dependent decrease of alpha-terpineol uptake was both due to decreases in stomatal conductance, g(w), and increased volatility of alpha-terpineol at higher temperature that decreased the monoterpene diffusion gradient between the ambient air (F(A)) and leaf (F(I); U = g(w)[F(A) - F(I)]). Model analyses suggested that alpha-pinene reacted within the leaf at higher temperatures, possibly within the lipid phase, thereby avoiding the decrease in diffusion gradient, F(A) - F(I). Thus, these data contribute to the hypothesis of the antioxidative protection of leaf membranes during heat stress by monoterpenes. These data further suggest that fumigation with the relatively low atmospheric concentrations of monoterpenes that are occasionally observed during warm windless days in the Mediterranean canopies may significantly improve the heat tolerance of nonemitting vegetation that grows intermixed with emitting species.

Efficiency of foam fractionation for the enrichment of nonpolar compounds from aqueous extracts of plant materials

Biologically active compounds from several useful plants were enriched using foam fractionation, a separatory method belonging to the adsorptive bubble separation (ABS). Nonpolar humulones (1-6) from Pilsener beer, curcuminoids (7-9) from turmeric, and carotenoids (16 and 17) from carrot juice were enriched fast and quantitatively, depending on the process parameters, whereas more polar compounds such as catechins from green tea (11, 12, 14, and 15) and naringin (18) and hesperidin (19) from orange and grapefruit juices could not be enriched.

Structure of an Atypical Epoxide Hydrolase from Mycobacterium tuberculosis Gives Insights into its Function

Epoxide hydrolases are vital to many organisms by virtue of their roles in detoxification, metabolism and processing of signaling molecules. The Mycobacterium tuberculosis genome encodes an unusually large number of epoxide hydrolases, suggesting that they might be of particular importance to these bacteria. We report here the first structure of an epoxide hydrolase from M.tuberculosis, solved to a resolution of 2.5 A using single-wavelength anomalous dispersion (SAD) from a selenomethionine-substituted protein. The enzyme features a deep active-site pocket created by the packing of three helices onto a curved six-stranded beta-sheet. This structure is similar to a previously described limonene-1,2-epoxide hydrolase from Rhodococcus erythropolis and unlike the alpha/beta-hydrolase fold typical of mammalian epoxide hydrolases (EH). A number of changes in the mycobacterial enzyme create a wider and deeper substrate-binding pocket than is found in its Rhodococcus homologue. Interestingly, each structure contains a different type of endogenous ligand of unknown origin bound in its active site. As a consequence of its wider substrate-binding pocket, the mycobacterial EH is capable of hydrolyzing long or bulky lipophilic epoxides such as 10,11-epoxystearic acid and cholesterol 5,6-oxide at appreciable rates, suggesting that similar compound(s) will serve as its physiological substrate(s).

Safranal, a constituent of Crocus sativus (saffron), attenuated cerebral ischemia induced oxidative damage in rat hippocampus

Increased oxidative stress has been implicated in the mechanisms of delayed neuronal cell death following cerebral ischemic insult. In this study, we investigated whether safranal, an active constituent of Crocus sativus L. stigmas, may ameliorate ischemia-reperfusion injury (IRI)-induced oxidative damage in rat hippocampus. Male NMRI rats were divided into six groups, namely, sham, control, ischemia and ischemia treated with safranal (four groups). The transient global cerebral ischemia was induced using four-vessel-occlusion method for 20 min. Safranal was injected intraperitoneally (727.5 mg/kg, 363.75 mg/kg, 145.5 mg/kg, and 72.75 mg/kg body weight) 5 min. prior to reperfusion and the administration was continued every 24 hours for 72 hours after induction of ischemia. The markers of oxidative stress including thiobarbituric acid reactive substances (TBARS), total sulfhydryl (SH) groups and antioxidant capacity of hippocampus (using FRAP assay) were measured. The transient global cerebral ischemia induced a significant increase in TBARS levels (p<0.001), decrement in both antioxidant power (FRAP value) (p<0.05) and total sulfhydryl (SH) concentrations (p<0.001) in comparison with sham-operated animals. Following safranal administration the total SH contents (3.2 vs. 0.7micromol/g, p<0.001, safranal 727.5 mg/kg) and antioxidant capacity (4.12 vs. 1.16 micromol/g, p<0.001; 727.5 mg/kg) were elevated in hippocampus in comparison with ischemic group. The MDA level was declined significantly in hippocampus (52.31 vs. 159.70 nmol/g, p<0.001; 727.5 mg/kg). It is concluded that safranal have some protective effects on different markers of oxidative damage in hippocampal tissue from ischemic rats.

Response of Plutella xylostella and its parasitoid Cotesia plutellae to volatile compounds

The effects of limonene, a mixture of limonene + carvone (1:1, v/v), and methyl jasmonate (MeJA) on diamondback moth (DBM) (Plutella xylostella L.) oviposition, larval feeding, and the behavior of its larval parasitoid Cotesia plutellae (Kurdjumov) with cabbage (Brassica oleracea L. ssp. capitata, cvs. Rinda and Lennox) and broccoli (B. oleracea subsp. Italica cv Lucky) were tested. Limonene showed no deterrent effect on DBM when plants were sprayed with or exposed to limonene, although there was a cultivar difference. A mixture of limonene and carvone released from vermiculite showed a significant repellent effect, reducing the number of eggs laid on the cabbages. MeJA treatment reduced the relative growth rate (RGR) of larvae on cv Lennox leaves. In Y-tube olfactometer tests, C. plutellae preferred the odors of limonene and MeJA to filtered air. In cv Lennox, the parasitoid preferred DBM-damaged plants with limonene to such plants without limonene. C. plutellae females were repelled by the mixture of limonene + carvone. In both cultivars, exogenous MeJA induced the emission of the sesquiterpene (E,E)-alpha-farnesene, the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), and green leaf volatile (Z)-3-hexenyl acetate + octanal. The attractive effect of limonene and MeJA predicts that these two compounds can be used in sustainable plant protection strategies in organic farming.

Effect of drying temperature and air flow on the production and retention of secondary metabolites in saffron

Safranal is the compound most responsible for the aroma of saffron spice and is, together with the suite of crocin pigments, the major determinant of the product quality. The content of safranal and pigments in saffron is determined by the method of postharvest treatment of the Crocus stigmas. A range of drying treatments involving different temperatures, with or without air flow, was applied to stigmas from three harvest dates. Dual solvent extractions combined with quantitative measurement using GC and HPLC-UV-vis techniques were used to analyze the secondary metabolite contents of the products. It was demonstrated that these methods overcame the previously reported problems in measuring the concentration of both pigments and safranal in saffron caused by the very different polarities and thus solubilities of these compounds. The results showed that a brief (20 min) initial period at a relatively high temperature (between 80 and 92 degrees C) followed by continued drying at a lower temperature (43 degrees C) produced saffron with a safranal content up to 25 times that of saffron dried only at lower temperatures. Evidence was provided suggesting that drying with significant air flow reduced the safranal concentration. The results, moreover, indicated that high-temperature treatment had allowed greater retention of crocin pigments than in saffron dried at intermediate temperatures (46-58 degrees C). The biochemical implications of the various treatments are discussed in relation to the potential for optimizing color and fragrance quality in the product.

Biocatalytic production of perillyl alcohol from limonene by using a novel Mycobacterium sp. cytochrome P450 alkane hydroxylase expressed in Pseudomonas putida

A number of oxygenated monoterpenes present at low concentrations in plant oils have anticarcinogenic properties. One of the most promising compounds in this respect is (-)-perillyl alcohol. Since this natural product is present only at low levels in a few plant oils, an alternative, synthetic source is desirable. Screening of 1,800 bacterial strains showed that many alkane degraders were able to specifically hydroxylate l-limonene in the 7 position to produce enantiopure (-)-perillyl alcohol. The oxygenase responsible for this was purified from the best-performing wild-type strain, Mycobacterium sp. strain HXN-1500. By using N-terminal sequence information, a 6.2-kb ApaI fragment was cloned, which encoded a cytochrome P450, a ferredoxin, and a ferredoxin reductase. The three genes were successfully coexpressed in Pseudomonas putida by using the broad-host-range vector pCom8, and the recombinant converted limonene to perillyl alcohol with a specific activity of 3 U/g (dry weight) of cells. The construct was subsequently used in a 2-liter bioreactor to produce perillyl alcohol on a scale of several grams.

On-line identification of secondary metabolites in freshwater microalgae and cyanobacteria by combined liquid chromatography–photodiode array detection-mass spectrometric techniques

The analysis and identification of a wide range of secondary metabolites biosynthesized by different algal taxa and cyanobacteria has been performed through a selective and sensitive methodology, mainly based on reversed-phase HPLC coupled both to UV photodiode array detection and to atmospheric pressure mass spectrometric techniques (HPLC-DAD-APIMS). Results are reported here with special attention to the analyses carried out both on the natural phytoplankton (mixed populations) of Lake Tovel (Northern Italy, Brenta Dolomites) and on enclosure-produced biomass of the dinoflagellate Glenodinium sanguineum Marchesoni (1941). This analytical procedure might represent a powerful tool for the fast screening of the taxonomic composition (broad groups, e.g. divisions) of natural mixed populations of phytoplankton, by providing a reliable distribution of accessory pigments extracted from microalgae, such as carotenoids and chlorophyll derivatives. Furthermore, we showed that in the same chromatographic analysis other classes of natural products, such as galactolipids, alkaloids, sterols and mycosporine-like amino acids, can be detected by using combined optical and mass spectrometric techniques. These metabolites represent distinctive biochemical signatures, sometimes even at the species level.

Feeding deterrent effects of catnip oil components compared with two synthetic amides against Aedes aegypti

Recently, catnip, Nepeta cataria L. (Lamiaceae), essential oil has been formulated and marketed as an alternative repellent for protection against biting arthropods by several vendors. We isolated the major active components of catnip oil, E,Z- and Z,E-nepetalactone, and quantitatively measured their antibiting efficacy compared with the repellents N,N-diethyl-3-methylbenzamide (deet) and chiral (1S,2'S)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) against the yellowfever mosquito, Aedes aegypti (L.), by using an in vitro assay and human volunteers at 24 nmol compound/cm2 (cloth or skin). Of all compounds tested in an in vitro assay, SS220 ranked as the most effective, whereas catnip oil and the nepetalactone compounds did not differ significantly from each other or from deet. However, in human volunteer bioassays, neither E,Z and Z,E-nepetalactone nor racemic nepetalactone deterred mosquito biting as effectively as SS220 or deet. All compounds differed significantly from the control. We conclude that catnip oil and nepetalactone isomers are significantly less effective than deet or SS220 in deterring the biting of Ae. aegypti.

Atherosclerotic lesion development in a novel ovary-intact mouse model of perimenopause

OBJECTIVE

Since the unexpected results from the Women's Health Initiative, the possible protective role of estrogen in preventing heart disease in perimenopausal and postmenopausal women is uncertain. This study examined atherosclerotic lesion development in ovariectomized versus follicle-depleted ovary-intact cholesterol-fed female low-density lipoprotein (LDL) receptor-deficient mice.

METHODS AND RESULTS

We studied lesion development in LDL receptor-deficient mice that were ovariectomized or follicle depleted with 4-vinylcyclohexene diepoxide (VCD) to induce ovarian failure, then treated +/- exogenous 17beta-estradiol via pellet implant. At 120 days after start of cholesterol feeding, the extent of lesion in aorta and innominate artery was determined. Lesion area in both locations was similar in vehicle control, VCD-treated, and ovariectomized mice. Replacement with 17beta-estradiol caused lesion reduction (P<0.05) in both arterial locations, but it was most efficacious in suppressing innominate lesion area in VCD-treated mice (12.9+/-5.2%) compared with ovariectomized mice (40.0+/-6.04%).

CONCLUSIONS

Endocrine status associated with the follicle-depleted ovary influences exogenous estradiol effects during the development of atherosclerotic lesions and, in particular, inhibits lesion progression in the innominate artery.

IKCa-channel blockers. Part 2: discovery of cyclohexadienes

Novel cyclohexadienes have been identified as potent and specific IK(Ca)-channel blockers. In this communication we describe their synthesis as well as their chemical and biological properties. A selected derivative is being enriched in rat brain and reduces the infarct volume, intracranial pressure as well as the water content in a rat subdural hematoma model of traumatic brain injury after iv administration.

Copolymerization of Cyclohexene Oxide with CO2 by Using Intramolecular Dinuclear Zinc Catalysts

The intramolecular dinuclear zinc complexes generated in situ from the reaction of multidentate semi-azacrown ether ligands with Et(2)Zn, followed by treatment with an alcohol additive, were found to promote the copolymerization of CO(2) and cyclohexene oxide (CHO) with completely alternating polycarbonate selectivity and high efficiency. With this type of novel initiator, the copolymerization could be accomplished under mild conditions at 1 atm pressure of CO(2), which represents a significant advantage over most catalytic systems developed for this reaction so far. The copolymerization reaction was demonstrated to be a living process as a result of the narrow polydispersities and the linear increase in the molecular weight with conversion of CHO. In addition, the solid-state structure of the dinuclear zinc complex was characterized by X-ray crystal structural analysis and can be considered as a model of the active catalyst. On the basis of the various efforts made to understand the mechanisms of the catalytic reaction, including MALDI-TOF mass analysis of the copolymers' end-groups, the effect of alcohol additives on the catalysis and CO(2) pressure on the conversion of CHO, as well as the kinetic data gained from in situ IR spectroscopy, a plausible catalytic cycle for the present reaction system is outlined. The copolymerization is initiated by the insertion of CO(2) into the Zn--OEt bond to afford a carbonate-ester-bridged complex. The dinuclear zinc structure of the catalyst remains intact throughout the copolymerization. The bridged zinc centers may have a synergistic effect on the copolymerization reaction; one zinc center could activate the epoxide through its coordination and the second zinc atom may be responsible for carbonate propagation by nucleophilic attack by the carbonate ester on the back side of the cis-epoxide ring to afford the carbonate. The mechanistic implication of this is particularly important for future research into the design of efficient and practical catalysts for the copolymerization of epoxides with CO(2.).

Isomerization and degradation kinetics of hop (Humulus lupulus) acids in a model wort-boiling system

The rate of isomerization of alpha acids to iso-alpha acids (the compounds contributing bitter taste to beer) was determined across a range of temperatures (90-130 degrees C) to characterize the rate at which iso-alpha acids are formed during kettle boiling. Multiple 12 mL stainless steel vessels were utilized to heat samples (alpha acids in a pH 5.2 buffered aqueous solution) at given temperatures, for varying lengths of time. Concentrations of alpha acids and iso-alpha acids were quantified by high-pressure liquid chromatography (HPLC). The isomerization reaction was found to be first order, with reaction rate varying as a function of temperature. Rate constants were experimentally determined to be k1 = (7.9 x 10(11)) e(-11858/T) for the isomerization reaction of alpha acids to iso-alpha acids, and k2 = (4.1 x 10(12)) e(-12994/T) for the subsequent loss of iso-alpha acids to uncharacterized degradation products. Activation energy was experimentally determined to be 98.6 kJ per mole for isomerization, and 108.0 kJ per mole for degradation. Losses of iso-alpha acids to degradation products were pronounced for cases in which boiling was continued beyond two half-lives of alpha-acid concentration.

Contributions of organic peroxides to secondary aerosol formed from reactions of monoterpenes with O3

The role of organic peroxides in secondary organic aerosol (SOA) formation from reactions of monoterpenes with O3 was investigated in a series of environmental chamber experiments. Reactions were performed with endocyclic (alpha-pinene and delta3-carene) and exocyclic (beta-pinene and sabinene) alkenes in dry and humid air and in the presence of the OH radical scavengers: cyclohexane, 1-propanol, and formaldehyde. A thermal desorption particle beam mass spectrometer was used to probe the identity and volatility of SOA components, and an iodometric-spectrophotometric method was used to quantify organic peroxides. Thermal desorption profiles and mass spectra showed that the most volatile SOA components had vapor pressures similar to pinic acid and that much of the SOA consisted of less volatile species that were probably oligomeric compounds. Peroxide analyses indicated that the SOA was predominantly organic peroxides, providing evidence that the oligomers were mostly peroxyhemiacetals formed by heterogeneous reactions of hydroperoxides and aldehydes. For example, it was estimated that organic peroxides contributed approximately 47 and approximately 85% of the SOA mass formed in the alpha- and beta-pinene reactions, respectively. Reactions performed with different OH radical scavengers indicated that most of the hydroperoxides were formed through the hydroperoxide channel rather than by reactions of stabilized Criegee intermediates. The effect of the OH radical scavenger on the SOA yield was also investigated, and the results were consistent with results of recent experiments and model simulations that support a mechanism based on changes in the [HO2]/[RO2] ratios. These are the first measurements of organic peroxides in monoterpene SOA, and the results have important implications for understanding the mechanisms of SOA formation and the potential effects of atmospheric aerosol particles on the environment and human health.

Oligonucleotides with cyclohexene-nucleoside building blocks: crystallization and preliminary X-ray studies of a left-handed sequence GTGTACAC

Cyclohexene nucleic acids contain a cyclohexene ring instead of the normal beta-D-2'-deoxyribose. The cyclohexene oligonucleotide GTGTACAC was synthesized using phosphoramidite chemistry and standard protecting groups. Crystals of GTGTACAC were obtained at 289 K by the hanging-drop vapour-diffusion technique. The crystals diffract to 1.7 A resolution and belong to the trigonal space group R3, with unit-cell parameters a = 41.434, c = 66.735 A.

Limonene, a citrus extract, for control of mealybugs and scale insects

In a series of bioassays with mealybugs, aqueous solutions of 1% limonene were tested that used from 0.50 to 1.50% all purpose spray adjuvant (APSA)-80 as an emulsifier/surfactant. The two ingredients were added to water or to 0.1% Silwet L-77, an agricultural surfactant. Using 1% limonene, 0.75% APSA-80 and 0.1% Silwet L-77, a semitransparent mixture (primarily a microemulsion) was obtained that was safe for most plants and provided good control of mealybugs when sprayed or used in 1-min dips. Used at half strength, this mixture controlled > or =99% of whiteflies, whereas the full-strength mixture controlled from 69 to 100% of mealybugs and scales, including > or =93% control of root mealybugs. In side-by-side greenhouse tests, this mixture was superior to a 2% solution of insecticidal soap or a 2% solution of horticultural spray oil. Mortality of green scales on potted gardenia plants averaged 95, 89, and 88% on plants sprayed with limonene, insecticidal soap, or horticultural oil, respectively. In a related test, these same sprays killed 44.1, 22.7, or 12.5% of third and fourth instar clustering mealybugs, respectively. Limonene has promise as a safe, natural pesticide for insect pests on tolerant plants. Although 1% limonene solutions damaged certain species of ferns, gingers and delicate flowers, they caused no damage to ornamentals with thick, waxy leaves, such as palms, cycads, and orchids.

Total asymmetric synthesis of (−)-conduramine B-1 and of its enantiomer. N-Benzyl derivatives of conduramine B-1 are β-glucosidase inhibitors

The 'naked sugars' (+)- and (-)-7-oxabicyclo[2.2.1]hept-5-en-2-one have been converted into (-)-conduramine B-1 ((-)-3) and its enantiomer (+)-3, respectively. They have been condensed with a variety of aldehydes in the presence of NaBH(OAc)(3). The N-substituted derivatives 4 and ent-4 so-obtained have been tested against two alpha-glucosidases, two amyloglucosidases, two beta-glucosidases and one beta-xylosidase for their inhibitory activities. Although (-)-3 and (+)-3 do not inhibit any of these enzymes at 1mM concentration, N-benzylated derivatives of (-)-conduramine B-1 are selective and competitive inhibitors of beta-glucosidases with K(i) in low micromolecular range.

Natural ozone scavenger prevents asthma in sensitized rats

The assumption that ozone is not only a strong oxidant, but also an important inflammatory mediator, is heavily supported by the ample literature on the pulmonary toxicity and biological effects of environmental ozone and by the recent discovery that antibodies, human neutrophils, and inflammatory lesions catalyze the formation of ozone in vivo. We hypothesized that the pulmonary inflammation in asthma involves a vicious circle of ozone production and recruitment of white blood cells, which produce more ozone. Accordingly, we predicted that electron-rich olefins, which are known ozone scavengers, could be used for prophylactic treatment of asthma. In particular, volatile, unsaturated monoterpenes, could saturate the pulmonary membranes and thereby equip the airways with local chemical protection against either exogenous or endogenous ozone. Here we present experimental evidence using a sensitized rat model to support this hypothesis. Examination of the pulmonary function of sensitized rats that inhaled either limonene (unsaturated, ozone scavenger) or eucalyptol (saturated, inert to ozone) showed that limonene inhalation significantly prevents bronchial obstruction while eucalyptol inhalation does not cause any effect. The anti-inflammatory effect of limonene was also evident from pathological parameters, such as diminished peribronchiolar and perivascular inflammatory infiltrates.

Dienophile twisting and substituent effects influence reaction rates of intramolecular Diels-Alder cycloadditions: a DFT study

Intramolecular cycloadditions of 5-vinyl-1,3-cyclohexadienes were studied with B3LYP/6-31G(d) density functional calculations. The one-atom tether dictates that the Z substituent becomes exo and the E substituent becomes endo in the TS. The geometry of the cycloaddition TS is typical of a pericyclic transformation except unusual twisting of the dienophile places the endo substituent in a relatively steric-free position and the exo substituent in a highly crowded position. The experimental rate differences between isomeric pairs of vinylcyclohexadienes can be explained by comparing reactant destabilization when a bulky group occupies the Z position of the starting alkene and transition state stabilization when a bulky group is endo in the cycloaddition TS.

An efficient synthesis of valienamine via ring-closing metathesis

An efficient synthesis of valienamine is described. Valienamine was synthesized starting from commercially available 2,3,4,6-tetra-O-benzyl-D-glucose in nine steps, using ring-closing metathesis of (4S,5S,6S)-4,5,6-tribenzyloxy-7-(benzyloxymethyl)octa-1,7-dien-3-ol as a key step.

Inhibition studies on salicylate synthase

Analogues of chorismate and isochorismate were designed and tested as potential inhibitors in the first inhibition study against a salicylate synthase.

The cytotoxic effect of two chemotypes of essential oils from the fruits of Angelica archangelica L

BACKGROUND

The aim of this work was to study the constituents and cytotoxicity of the essential oils from the fruits of Angelica archangelica growing in Iceland.

MATERIALS AND METHODS

Three samples of essential oils were prepared by steam distillation. Their composition was established with GC/MS. The effects of the oils were examined in PANC-1 human pancreas cancer cells and Crl mouse breast cancer cells in concentrations ranging from 10-400 microg/ml, measuring the reduction of the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl) -5- (3-carboxymethoxyphenyl)-2- (4-sulphophenyl) -2H-tetrazolium (MTS) by mitochondrial enzymes.

RESULTS

Two types of essential oils were found, differing mainly in the absence or presence of beta-phellandrene. The ED50 of the oils ranged from 48.6 microg/ml to 108.3 microg/ml for PANC-1 and 48.0 microg/ml to 91.8 microg/ml for Crl cells.

CONCLUSION

The cytotoxic activity of the essential oils was independent of the quantity of their main components.

[Study on preparation technology of limonene dropping pills]

OBJECTIVE

To study the technical preparation of limonene dropping pills.

METHODS

Orthogonal test was applied to optimize the preparation of limonene dropping pills.

RESULTS

The optimized project was as follow: the matrix contained PEG4000: PEG6000 (1:1.5); the refrigerant was liquid paraffin; the rate of limonene to matrix was 1:6 and the temperature of limonene was 70 degrees C; the internal and external diameter of burette was 2.0 mm and 2.4 mm, respectively; the burette was 4cm above the surface of refrigerant; drug was dropped into refrigerant of 15 degrees C at 45 drops per minute.

CONCLUSION

The results provide the data for the ascertainment of shaping operation of limonene dropping pills at the manufacturing scale.

Partially and fully β-brominated Mn-porphyrins in P450 biomimetic systems: Effects of the degree of bromination on electrochemical and catalytic properties

Beta-hexabromo-5,10,15,20-tetrakis(4-carbomethoxyphenyl)porphyrinatomanganese(III) chloride (Mn(III)(Br6TCMPP)Cl) was prepared by selective Br2-hexabromation of its parent non-brominated manganese complex (Mn(III)(TCMPP)Cl), whereas the octabrominated analogue beta-octabromo-5,10,15,20-tetrakis(4-carbomethoxyphenyl)porphyrinatomanganese(III) chloride (Mn(III)(Br8TCMPP)Cl) was synthesized via metallation of the corresponding free-base. Beta-octabromo-5,10,15,20-tetrakis(4-carbomethoxyphenyl)porphyrin was obtained by demetallation of its brominated Cu(II) derivative, which, in its turn, was prepared by either a Br2 or an N-bromosuccinimide protocol. Relative to Mn(III)(TCMPP)Cl (E(1/2) = -0.16 V vs. normal hydrogen electrode, CH2Cl2), the Mn(III)/Mn(II) reduction potential of Mn(III)(Br8TCMPP)Cl and Mn(III)(Br6TCMPP)Cl showed anodic shifts of 0.43 and 0.33 V, respectively, which corresponded to a linear shift of 0.05 V per bromine added. These manganese complexes were evaluated as cytochrome P450 mimics in catalytic iodosylbenzene (PhIO)-oxidations of cyclohexane and cyclohexene. In aerobic PhIO-oxidation of cyclohexene, epoxidation and allylic autoxidation reactions were inversely related, competitive processes; the most efficient P450-mimics were the least effective autoxidation catalysts. Mn(III)(Br6TCMPP)Cl was more efficient as epoxidation or hydroxylation catalyst than both its fully and non-beta-brominated counterparts were. There was no linear relationship between the catalytic efficiency and both the number of bromine substituents and the Mn(III)/Mn(II) potential; these observations were compared to Lyons system literature data and discussed. Analogously to enzymatic optimum pH effects, an optimum redox potential effect is suggested as relevant in designing and understanding cytochrome P450 biomimetic catalysts.