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PubMed2001

Reinvestigation of the reactions of camphorketene: structural evidence for pseudopericyclic pathways.

The stereochemistry of the dimers (3 and 4) of camphorketene (2) have been determined. The crystal structures of 3, 20 and of related compounds show ground-state distortions that are interpreted as prefiguring planar, pseudopericyclic transition states for retro-cycloadditions to form alpha-oxoketenes. The B3LYP/6-31G* optimized geometry for the transition structure (10) for the dimerization of s-Z-formylketene (8) is consistent with this mechanism. Trapping of 2 with alcohols shows selectivity comparable to other alpha-oxoketenes. The lack of reaction of 2 with benzaldehyde and the lack of enol tautomers in camphoric acid derivatives is attributed to angle strain in the bicyclic camphor moiety.

Journal Article↗
PubMed2005

Organoaluminium complexes with sterically demanding oximato ligands: does a bulky and rigid ligand backbone change the aggregation motif?

The four organoaluminium ketoximates [(2,4-dimethylpentane-3-one oximato)AlMe(2)](2) (1), (meso)-[(norcamphor oximato)AlMe(2)](2) (2), {[(R,R)-camphor oximato]AlMe(2)}(3) (3) and {[(R,S)-fenchone oximato]AlMe(2)}(2) (4) have been prepared by the reactions of the corresponding oximes with trimethylaluminium. All compounds have been fully characterized by means of IR, mass and multi-nuclear NMR spectroscopy ((1)H, (13)C, (27)Al) and by elemental analyses. The crystal structures of three of these compounds (2, 3 and 4) were determined, revealing the aggregation motif of organometallic group 13 oximates to vary from the hitherto predominant six-membered dimeric M(2)N(2)O(2) array to others (six-membered M(3)O(3) core ring in the case of the camphor derivative; five-membered M(2)NO(2) core ring in the case of the fenchone derivative) so far only found e.g. in hydroxylamino complexes of group 13 metals. Furthermore, complexes 3 and 4 exhibit an unusual behaviour in solution, as indicated by upfield-shifted additional signals in their (27)Al NMR spectra, pointing at aluminium atoms in penta- or hexacoordination, respectively.

Journal Article↗
PubMed1970

Spin-state changes in cytochrome P-450cam on binding of specific substrates.

The electron paramagnetic resonance signals of the soluble P-450 cytochrome from Pseudomonas putida were observed at temperatures from 4.2 to 80 degrees K. As isolated, P-450 has a signal typical of a low spin ferric-heme compound with sulfur as one of the axial ligands (g = 2.45, 2.26, 1.91(5)). We also detected a minor signal typical of high spin ferric heme (g = 8, 4, 1.8) equivalent to less than 7% of the heme at temperatures below 20 degrees K. On titration with the substrate, (+)-camphor, the low spin signal decreased and the high spin signal increased, maximally representing about 60% of the heme. For reasons not thus far understood, 40% of the heme is not converted to high spin by either (+) or (-)-camphor. The high spin signal has a rhombic character which is stronger than any previously observed with a heme compound (E = 0.33 cm(-1); D = 3.8 cm(-1); E/D = 0.087). We conclude that P-450(cam) as isolated is equal to or more than 95% in a low spin form probably having sulfur as one of the axial ligands. The binding of substrate displaces this ligand sufficiently to allow for conversion from a low to a high spin form.

Cold Temperature↗
PubMed1982

Chemical mechanisms for cytochrome P-450 oxidation: spectral and catalytic properties of a manganese-substituted protein.

Bacterial cytochrome P-450 induced by camphor (P-450cam) is reconstituted with manganese-protoporphyrin IX, yielding an enzyme that displays unique spectral properties relative to previously characterized manganese-porphyrin systems. The nitric oxide complex of the manganese(II)-protein shows a hyper-metalloporphyrin spectrum suggestive of thiolate ligation to the porphyrin-bound manganese ion. In the presence of iodosobenzene as a source of active oxygen, manganese-substituted cytochrome P-450cam serves as a catalyst for the epoxidation of an enzyme-bound olefin substrate. This reactivity proceeds through a spectrally detectable intermediate that resembles the manganese(V)-oxo complexes that have been well documented with model systems employing artificial manganese-metalloporphyrins in organic solution. Interestingly, manganese-substituted cytochrome-P-450cam shows no hydroxylation activity either in the reconstituted camphor hydroxylase system with pyridine nucleotide or in the presence of iodosobenzene and the Mn(III) form of the protein.

Cytochrome P-450 Enzyme System↗
PubMed1995

Measurements of CO geminate recombination in cytochromes P450 and P420.

The kinetics of CO geminate recombination in cytochrome P450cam are studied at room temperature subsequent to laser photolysis. The geminate rebinding kinetics of P450 are strongly affected by the presence of the camphor substrate. We observe a approximately 2% geminate yield for substrate-bound P450 and a 90% geminate yield when the substrate is absent. The drastic difference in the geminate kinetics suggests that the presence of camphor significantly alters the CO rebinding and escape rates by modifying the heme pocket environment. Two geminate phases and two bimolecular rebinding phases in the substrate free protein were observed, which could arise from slowly interconverting protein conformations. When the temperature or the viscosity of the solution is changed, the fast geminate rate remains the same, whereas the slow geminate rate and the two bimolecular rates change significantly. The geminate rebinding yield of substrate-free P420 is smaller than that of substrate free P450, but its geminate rebinding rate is faster. This demonstrates that in the absence of substrate, CO escapes from the pocket of P420 much more rapidly than from P450 and suggests that the distal pocket environment is altered in the P420 form.

Carbon Monoxide↗
PubMed2001

Headspace constituents of the tree remain of Cinnamomum camphora.

The volatile ingredients isolated from a fresh tree of Cinnamomum camphora (camphor tree) and from a tree remain of C. camphora were collected by using headspace techniques and analyzed by means of gas chromatography/mass spectrometry (GC/MS). 99.77% of the constituents consisting 23 components from the fresh tree, 98.68% of the constituents consisting 24 components from the tree remain were identified. Of these ingredients, camphor was obtained as the most abundant component.

Gas Chromatography-Mass Spectrometry↗
PubMed2006

Comparison of composition and antifungal activity of Artemisia argyi Lévl. et Vant inflorescence essential oil extracted by hydrodistillation and supercritical carbon dioxide.

Essential oil of Artemisia argyi Lévl. et Vant inflorescence was obtained by supercritical CO(2) extraction and hydrodistillation. The oil was analyzed by gas chromatography/mass spectrometry to characterize its components and was also tested for antifungal activity. A total of 61 compounds were identified in the hydrodistilled oil. The major components were 1,8-cineole (4.46%), borneol (3.58%), terpinol (10.18%), spathulenol (10.03%), caryophyllene oxide (6.51%), juniper camphor (8.74%), Camazulene (2.05%), and camphor (3.49%). By using supercritical CO(2) at 50 degrees C and 10 MPa, the concentrations of previous main components were lower than oil obtained by hydrodistillation, while miscellaneous compounds were higher. The essential oil extracted by these two methods exhibited antifungal activity against Botrytis cinerea and Alternaria alternate, two common storage pathogens of fruits and vegetables. The inhibition of B. cinerea and A. alternate were 93.3 and 84.7% for oil extracted by hydrodistillation when exposed to a concentration of 1,000 mg L(-1), while values of 70.8 and 60.5% were observed from oil extracted by supercritical CO(2).

Alternaria↗
PubMed2003

UV filters with antagonistic action at androgen receptors in the MDA-kb2 cell transcriptional-activation assay.

The fact that certain ultraviolet (UV) filters used in cosmetics display estrogenic activity prompted us to study potential actions on androgen receptors (AR) in the human breast carcinoma cell line MDA-kb2, which expresses functional endogenous AR and glucocorticoid receptors (GR) and is stably transfected with a luciferase reporter plasmid. Dihydrotestosterone (DHT), methyltrienolone (R1881), methyltestosterone, danazol, and androstenedione increased luciferase activity, with EC50 values between 0.11 nM (R1881), 0.14 nM (DHT), and 73.5 nM (androstenedione). DHT-induced luciferase gene expression was inhibited by nonsteroidal antiandrogens, hydroxyflutamide, flutamide, bicalutamide, and vinclozolin. In contrast, the steroidal AR agonist/antagonist cyproterone actetate showed agonistic activity in the absence and presence of DHT, which was not blocked by hydroxyflutamide and thus seems not to be mediated by AR. GR-mediated activation of luciferase by dexamethasone was 100 times less potent than DHT and was not antagonized by hydroxyflutamide. The cell line was used for screening of UV filters, benzophenone-3 (Bp-3), benzophenone-4, 3-benzylidene camphor, 4-methylbenzylidene camphor, butyl-methoxy-dibenzoylmethane, homosalate (HMS), octyl-dimethyl-PABA, and octyl-methoxycinnamate. Two of these, Bp-3 and HMS, antagonized DHT-induced AR activation below cytotoxic concentrations, with IC50 of 5.57 10-6 M (HMS) and 4.98 10-6 M (Bp-3). None of the eight UV filters displayed agonistic activity when tested alone, but high concentrations of Bp-3 induced an increase of luciferase activity in the presence of dexamethasone, which was not blocked by hydroxyflutamide or the estrogen antagonist, ICI 182,780. These data indicate that the UV filters Bp-3 and HMS possess antiandrogenic activity in vitro in addition to estrogenic activity.

Arsenic↗
PubMed2004

Interaction of polycyclic musks and UV filters with the estrogen receptor (ER), androgen receptor (AR), and progesterone receptor (PR) in reporter gene bioassays.

Two important ingredients of personal care products, namely polycyclic musk fragrances and UV filters, can be found in the environment and in humans. In previous studies, several compounds of both classes have been tested for their interaction with the estrogen receptor. Two polycyclic musk fragrances, namely AHTN and HHCB, turned out to be anti-estrogenic both in vitro and in vivo in a transgenic zebrafish assay. Several UV filters have been shown to exert estrogenic effects in vitro and in some in vivo studies. Here, we assessed the interaction of five polycyclic musk compounds and seven UV filters with the estrogen receptor (ER), androgen receptor (AR), and progesterone (PR) receptor, using sensitive and specific reporter gene cell lines. Four polycyclic musks (AHTN, HHCB, AETT, and AHMI) were found to be antagonists toward the ERbeta, AR and PR. The UV filters that showed estrogenic effects (benzophenone-3, Bp-3; 3-benzylidene camphor, 3-BC; homosalate, HMS; and 4-methylbenzylidene camphor, 4-MBC) were found to be antagonists toward the AR and PR. The ERalpha agonistic UV filter octyl-dimethyl-p-aminobenzoic acid (OD-PABA) did not show activity toward the AR and PR. Octyl methoxy cinnamate (OMC) showed weak ERalpha agonism, but potent PR antagonism. Butyl methoxydibenzoylmethane (B-MDM) only showed weak ERalpha agonism and weak AR antagonism. Most effects were observed at relatively high concentrations (above 1 muM); however, the anti-progestagenic effects of the polycyclic musks AHMI and AHTN were detected at concentrations as low as 0.01 muM. The activity of anti-progestagenic xenobiotics at low concentrations indicates the need to undertake more research to find out about the potential endocrine disrupting effects of these compounds in vivo.

Benzopyrans↗
PubMed2002

Ecophysiological characteristics of Taiwan alder (Alnus formosana) seedlings adapted to the subtropical region.

We investigated several ecophysiological characteristics of seedlings of a low-elevation (100-200 m) and a high-elevation (2000-2400 m) population of Taiwan alder (Alnus formosana Makino) from subtropical Taiwan. Both populations had a wide optimal temperature range for photosynthesis, and there was little difference in the optimal temperature range for photosynthesis between populations. Photosynthetic rate (P(N)) was near maximal from 20 to 35 degrees C when seedlings of both the low-elevation and the high-elevation populations were acclimated at a day/night temperature of 30/23 degrees C. When seedlings were acclimated at a day/night temperature of 20/10 degrees C, P(N) was near maximal over the range 15-35 degrees C in the low-elevation population and 15-30 degrees C in the high-elevation population. Compared with nine other tree species native to Taiwan, Taiwan alder had a high P(N) and stomatal conductance (g(s)) under well-watered conditions. Reflecting its higher transpiration rate, Taiwan alder had a significantly greater leaf-air temperature difference than camphor (Cinnamomum camphora (L.) J. Presl), a co-occurring lowland tree species with leaves similar in shape and size to those of Taiwan alder. Despite higher g(s), high root and shoot hydraulic conductances enabled Taiwan alder to maintain higher leaf water potentials than camphor under well-watered conditions. We conclude that both photosynthetic characteristics and water relations are important factors enabling Taiwan alder to adapt to a wide temperature range, thereby ensuring its success at both high and low elevations in subtropical Taiwan.

Acclimatization↗
PubMed2002

A comparison of the antimicrobial efficacy of three calcium hydroxide formulations on human dentin infected with Enterococcus faecalis.

This study compared the antibacterial efficacy of three different formulations of calcium hydroxide by using human dentin specimens that were infected with Enterococcus faecalis. After exposure to three forms of calcium hydroxide (calcium hydroxide mixed with distilled water, calcium hydroxide mixed with 0.2% chlorhexidine, and calcium hydroxide mixed with camphorated paramonochlorophenol) for 7 days, dentin powder from the infected specimens was obtained and assessed for bacterial quantity by spectrophotometry. It was found that calcium hydroxide mixed with camphorated paramonochlorophenol killed all of the Enterococcus faecalis inside the dentinal tubules. This result was better than that obtained with calcium hydroxide mixed with distilled water or with 0.2% chlorhexidine (p < 0.05). Calcium hydroxide mixed with distilled water and calcium hydroxide mixed with 0.2% chlorhexidine were ineffective against these bacteria.

Anti-Infective Agents, Local↗
PubMed2001

[eta(2)-(E)-But-2-enedinitrile](N,N'-di-phenyl-1,7,7-trimethylbicyclo[2.2.1]-heptane-2,3-diimine-N,N')-palladium(0).

The zero-valent palladium in [Pd(C(4)H(2)N(2))(C(22)H(24)N(2))] is coordinated to two imine N atoms of a derivatized camphor ligand, and to the olefinic C atoms of a pi-bonded fumaronitrile group. The N--Pd--N bite angle of 77.31 (9) degrees is similar to angles observed in other zero-valent palladium diiminoalkene species. The asymmetry of the camphor moiety leads to two different orientations of the N-aryl groups relative to the PdN(2) plane [C==N--C--C torsion angles of 102.4 (4) and 39.4 (4) degrees ].

Journal Article↗
PubMedDate not supplied

Determination of penetration profiles of topically applied substances by means of tape stripping and optical spectroscopy: UV filter substance in sunscreens.

Penetration profiles of topically applied drugs and cosmetic products provide important information on their efficacy. The application of tape stripping in combination with UV/VIS spectroscopy is checked to determine the local position of topically applied substances inside the stratum corneum, the penetration profile. The amount of corneocytes removed with each tape strip is quantified via the particle-dependent absorption, the pseudoabsorption, in the visible spectral range. The concentration of a typical UV filter substance, 4-methylbenzylidene camphor, is determined by optical spectroscopy using the tape strips removed originally. In this case, a time-dependent increase in the absorbance must be taken into account. Laser scanning microscopic investigations confirm that the nonhomogeneous distribution of the filter substance, on the strips, can explain this spectroscopic behavior. When reaching a homogeneous distribution, the UV spectroscopic signal reflects the correct concentration. These spectroscopic values are compared with high performance liquid chromatography (HPLC) data. The values obtained with both methods for the concentrations of 4-methylbenzylidene camphor are in good agreement. The data obtained are used to illustrate the determination of a penetration profile of a UV filter substance. The results demonstrate that the described protocol is well suited to characterize, in a simple manner, topically applied substances that have a characteristic UV/VIS absorption band.

Administration, Cutaneous↗
PubMed1979

Transposition of Tn7 in Pseudomonas aeruginosa and isolation of alk::Tn7 mutations.

Conjugal crosses with Pseudomonas aeruginosa donors carrying the CAM-OCT and RP4::Tn7 plasmids result in transfer of the Tn7 trimethoprim resistance (Tp(r)) determinant independently of RP4 markers. All Tp(r) exconjugants which lack RP4 markers have CAM-OCT genes and therefore must have received CAM-OCT::Tn7 plasmids formed by transposition of Tn7 from RP4::Tn7 to CAM-OCT. Most crosses yield exconjugants carrying mutant CAM-OCT plasmids which no longer determine either camphor or alkane utilization and thus appear to carry Tn7 inserts in the cam or alk loci, respectively. Transduction and reversion experiments indicated that at least 13 alkane-negative, camphor-positive, Tp(r) CAM-OCT::Tn7 plasmids carry an alk::Tn7 mutation. Determination of linkage between the alk mutation and the Tp(r) determinant of Tn7 on these plasmids is complicated by the presence of multiple copies of the Tn7 element in the genome. Generalized transduction will remove Tn7 from a CAM-OCT alk::Tn7 plasmid to yield alk(+) cells which carry no Tp(r) determinant on the CAM-OCT plasmid (as shown by transfer of the plasmid to a second strain). But the transduction to alk(+) does not remove all Tp(r) determinants from the genome of the recipient cell because the alkane-positive transductants remain trimethoprim resistant. Thus, it appears that copies of Tn7 can accumulate in the genome of P. aeruginosa (CAM-OCT alk::Tn7) strains without leaving their original site. This result is consistent with transposition models that involve replication of the transposable element without excision from the original site.

Alkanes↗
PubMed1994

Efferent signal(s) responsible for the conditioned augmentation of natural killer cell activity.

In in vivo studies, a conditioned increase in NK cell activity can be obtained by pairing odor of camphor (conditioned stimulus, CS) with poly I:C (unconditioned stimulus, US) in a single-association paradigm. We identified interferon (IFN) as the signal that reaches the central nervous system (CNS) to make an association with the camphor CS. We have also established that the CS/US association is an IFN-dependent step, and the expression stage is an opioid-dependent pathway which can be blocked with naltrexone and dexamethasone. Here we have focused on the signals responsible for the expression of conditioned augmentation of natural killer (NK) cell activity. The possible efferent signal molecules that were considered were IFN, beta-endorphin (beta-END), and adrenocorticotropic hormone (ACTH). Plasma levels of beta-END and ACTH of conditioned and control mice were quantitated by radioimmunoassay, and the changes in IFN message in the spleen cells were determined by Northern hybridization analysis. Results indicate that the ACTH levels and IFN-alpha gene expression were higher in the conditioned animals than in the controls. These studies support the view that ACTH released from the pituitary gland is involved in the up-regulation of IFN-alpha, which in turn stimulates the NK cells in the spleen.

Adrenocorticotropic Hormone↗
PubMed2001

In-vitro activity of S. lavandulaefolia (Spanish sage) relevant to treatment of Alzheimer's disease.

Salvia lavandulaefolia Vahl. (Spanish sage) essential oil and individual monoterpenoid constituents have been shown to inhibit the enzyme acetylcholinesterase in-vitro and in-vivo. This activity is relevant to the treatment of Alzheimer's disease, since anticholinesterase drugs are currently the only drugs available to treat Alzheimer's disease. Other activities relevant to Alzheimer's disease include antioxidant, anti-inflammatory and estrogenic effects. Results of in-vitro tests for these activities are reported here for S. lavandulaefolia extracts, the essential oil and its major constituents. Antioxidant activity (inhibition of bovine brain liposome peroxidation) was found in the EtOH extract of the dried herb (5 mg mL(-1)) and the monoterpenoids (0.1 M) alpha- and beta-pinene and 1,8-cineole. Thujone and geraniol had lower antioxidant effects, while camphor had no antioxidant effects. Possible anti-inflammatory activity (eicosanoid inhibition in rat leucocytes) was found in the EtOH extract (50 microg mL(-1)) and was shown by the monoterpenoids alpha-pinene and geraniol (0.2 mM), but not 1,8-cineole, thujone or camphor. Possible estrogenic activity (via induction of beta-galactosidase activity in yeast cells) was found in the essential oil (0.01 mg mL(-1)) and the monoterpenoid geraniol (0.1-2 mM). 1,8-Cineole, alpha- and beta-pinene and thujone did not exhibit estrogenic activity in this analysis. These results demonstrate that S. lavandulaefolia, its essential oil and some chemical constituents have properties relevant to the treatment of Alzheimer's disease and provide further data supporting the value of carrying out clinical studies in patients with Alzheimer's disease using this plant species.

Alzheimer Disease↗
PubMed2002

[Quality evaluation of essential oils].

Essential oils on the market were analyzed using GC-MS and the main ingredients of each essential oil were quantified. Analysis of the essential oil of Lavandula officinalis (lavender oil) showed that each sample had a different ratio of the contents of main ingredients, such as linalool, linalyl acetate, and camphor. In addition, some commercial lavender oils were analyzed by GC-MS for comparison with the Lavandula flagrans (lavandin oil) and the reference standard. As a result of this analysis, although the components of almost all commercial lavender oils were approximately the same as those of the reference standard, there were a few products that contained more than 0.5% of the amount of camphor in lavandin oil. This suggests that some lavender oil samples are mixed with lavandin oil to lower the price. Commercial essential oils of Melaleuca alternifolia (teatree oil) and Mentha piperita (peppermint oil) were also analyzed by GC-MS. Each of the peppermint oil samples had a different ratio in the content of its main ingredient. With respect to teatree oils, the amount of terpinens in each sample differed. These results led to concern about the efficacy of essential oils. For achieve the expected efficacy of essential oils, correct information on their ingredients should be available and quality control using instrumental analysis should be introduced.

Gas Chromatography-Mass Spectrometry↗
PubMed1982

Insights into the active site of the cytochrome P-450 haemoprotein family--a unifying concept based on structural considerations.

1. Cytochromes P-450CAM of Pseudomonas putida and P-450LM-2 of rabbit liver, and to a lesser extent also adrenocortical mitochondrial cytochromes P-450(11) beta and P-450SCC, were investigated by active site-targeted reagents and by immunochemical techniques. The results of these studies and of the alignment of the amino acid sequences of cytochromes P-450CAM and of phenobarbital-induced rat-liver P-450LM support the following conclusions. 2. Cytochrome P-450 haemoproteins follow a common architectural design, most readily apparent in the surroundings of the haem group. Sequence homology and associated folding leads to immunochemical similarities revealed by radioimmune assay. 3. The haem domain is partially exposed on the surface of the protein. This part appears to be tightly structured from several distinct portions of the polypeptide chain which carry the haem catalytic site and the substrate binding site, respectively. 4. After photocovalent labelling with substrate- or inhibitor-derived arylazido reagents, a substantial portion of the haem domain may be excised by BrCN or formic acid and purified without loss of haem ('haemopeptide'). A major antibody-binding site is associated with this fragment. 5. Exploration of the haem pocket of cytochrome P-450CAM, using bromoacetyl and mercapto derivatives of its substrate, camphor, revealed an activated SH group responsible for binding and precision alignment of camphor toward the haem iron, presumably by forming a transient thiohemiketal bond. This cysteine may also function in translocation of nascent product for facilitated release. Specific terpenoid substrates of other cytochrome P-450 haemoproteins may be bound in a similar manner. 6. From radiolabelled peptide studies the substrate-binding cysteine was identified as residue 56 in the amino acid sequence of cytochrome P-450CAM. The haemchelating cysteine occupies position 134 or 146 in cytochrome P-450CAM and position 152 or 173 in cytochrome P-450LM, respectively.

Affinity Labels↗