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PubMed2000

Molecular cloning and functional expression of a stress-induced multifunctional O-methyltransferase with pinosylvin methyltransferase activity from Scots pine (Pinus sylvestris L.).

Formation of pinosylvin (PS) and pinosylvin 3-O-monomethyl ether (PSM), as well as the activities of stilbene synthase (STS) and S-adenosyl-1-methionine (SAM):pinosylvin O-methyltransferase (PMT), were induced strongly in needles of Scots pine seedlings upon ozone treatment, as well as in cell suspension cultures of Scots pine upon fungal elicitation. A SAM-dependent PMT protein was purified and partially characterised. A cDNA encoding PMT was isolated from an ozone-induced Scots pine cDNA library. Southern blot analysis of the genomic DNA suggested the presence of a gene family. The deduced protein sequence showed the typical highly conserved regions of O-methyltransferases (OMTs), and average identities of 20-56% to known OMTs. PMT expressed in Escherichia coli corresponded to that of purified PMT (40 kDa) from pine cell cultures. The recombinant enzyme catalysed the methylation of PS, caffeic acid, caffeoyl-CoA and quercetin. Several other substances, such as astringenin, resveratrol, 5-OH-ferulic acid, catechol and luteolin, were also methylated. Recombinant PMT thus had a relatively broad substrate specificity. Treatment of 7-year old Scots pine trees with ozone markedly increased the PMT mRNA level. Our results show that PMT represents a new SAM-dependent OMT for the methylation of stress-induced pinosylvin in Scots pine needles.

Amino Acid Sequence↗
PubMed2001

Overexpression of a heterologous sam gene encoding S-adenosylmethionine synthetase in flax (Linum usitatissimum) cells: Consequences on methylation of lignin precursors and pectins.

The Arabidopsis thaliana sam1 gene encoding S-adenosylmethionine synthetase (EC 2.5.1.6) was transferred to flax (Linum usitatissimum) cells via Agrobacterium tumefaciens. This enzyme catalyses the conversion of methionine to S-adenosylmethionine (SAM), the major methyl group donor in living cells. The aim of this work was to study the consequences of an increased SAM-synthetase (SAM-S) activity in transgenic cell lines on both the production of mono- and dimethoxylated lignin monomers and the degree of methylesterification of pectins. Hypocotyls were cocultivated with Agrobacterium tumefaciens strain GV3101 (pGV2260) harbouring the pO35SSAM binary vector carrying the sam1 gene under the control of the 35S promoter and the nptII gene for selection of putative transformed cells. Most of the transgenic cell lines exhibited a significant (up to 3.2-fold) increase in SAM-S activity compared to the controls. The results showed that for the cell lines analysed this transformation had no effect on caffeic acid O-methyltransferase (COMT, EC 2.1.1.68) in vitro activity, degree of methoxylation of lignin precursors or lignin deposition, pectin methyltransferase (PMT, EC 2.1.1) in vitro activity, but led to an increase of pectin methylesterification in friable and fast-growing transgenic cell lines.

Journal Article↗
PubMed2000

Tonality of suntan vs sunless tanning with dihydroxyacetone.

BACKGROUND/AIMS: Although there is an increasing awareness of the detrimental effects of solar irradiation on skin, a tanned look is still in fashion. To achieve the tanned look without sun exposure various sunless tanning formulations have become available. Most of these contain dihydroxyacetone (DHA) which binds to the proteins of the stratum cornium and imparts a brown color to skin. This color is similar to a suntan but can be somewhat more yellow, making it appear unnatural. The aim of this study was to determine a quantitative method to define a "natural" tan and to study methods to improve the tonality of sunless tanning on skin. METHODS: Tonality of suntan was determined as the marker for a "natural" tan. In order to achieve this, human volunteers were exposed to the sun and the change in skin color was observed after 3 days. Color measurements obtained with the Minolta Chromameter were plotted in two standard graphs labeled as the "natural universe of tan", which depicted a balance between Chroma and change in reflectance, while the "natural universe of color" determined the balance between changes in yellow and red components of the suntan. Change in skin color after treatment with DHA was then inserted in these graphs to observe how "natural" the tonality of sunless tan appeared relative to suntan. RESULTS: Results show a good balance between Chroma and change in reflectance for suntanned skin in the "natural universe of tan". Conversely, the "natural universe of color" exhibited a good balance between increase in yellow and red components of suntan. Sunless tan data inserted in these graphs showed that for several subjects with skin types I-II the tonality is not within the realm of "natural" but is unnaturally yellow. Addition of antioxidants, especially caffeic acid phenethyl ester (CAPE) in DHA formulation significantly shifted the tonality towards the center of the "natural universe of color". CONCLUSIONS: The "natural universes of tan and color" exhibit a simple and quantitative assessment of tonality of suntan and sunless tan. Although skin tonality from DHA-induced sunless tan can often lie outside the realm of the "natural" tan, it is possible to improve this tonality to a more "natural" look by addition of strong antioxidants in the DHA formulations.

Journal Article↗
PubMed1995

Molecular mechanisms of tirapazamine (SR 4233, Win 59075)-induced hepatocyte toxicity under low oxygen concentrations.

Previously we showed that tirapazamine (SR 4233, Win 59075) is cytotoxic towards hepatocytes under conditions of hypoxia but not in 10% or 95% oxygen and that bioreduction by DT-diaphorase or cytochrome P450 is not a major pathway. In the present study, we report that tirapazamine is highly cytotoxic to isolated rat hepatocytes maintained under 1% oxygen and the molecular cytotoxic mechanism has been elucidated. Cytotoxicity was prevented by the cytochrome P450 2E1 inhibitors phenyl imidazole, isoniazid, isopropanol or ethanol, suggesting that cytochrome P450 2E1 catalysed tirapazamine reductive bioactivation. By contrast, dicoumarol, a DT-diaphorase inhibitor, markedly increased tirapazamine-induced cytotoxicity. Cytotoxicity was also inhibited in normal but not DT-diaphorase-inactivated hepatocytes by increasing cellular NADH levels with lactate or ethanol or the mitochondrial respiratory inhibitors. Evidence that oxygen activation contributed to cytotoxicity was that glutathione oxidation occurred well before cytotoxicity ensued and that tirapazamine was more cytotoxic towards catalase- or glutathione reductase-inactivated hepatocytes. Furthermore, polyphenolic antioxidants such as quercetin, caffeic acid or purpurogallin, the radical trap Tempol or the iron chelator desferrioxamine prevented tirapazamine-mediated cytotoxicity. However, the antioxidants diphenylphenylenediamine, butylated hydroxyanisole or butylated hydroxytoluene did not prevent cytotoxicity and malonaldehyde formation was not increased, suggesting that lipid peroxidation was not important. The above results suggest that DT-diaphorase detoxifies tirapazamine whereas reduced cytochrome P450 reduces tirapazamine to a nitrogen oxide anion radical which forms cytotoxic reactive oxygen species as a result of redox cycling.

Animals↗
PubMed2002

IL-1 beta signalling in glial cells in wildtype and IL-1RI deficient mice.

1. Interleukin-1 (IL-1) has been implicated in neurodegeneration and in central nervous system (CNS)-mediated host defence responses to inflammation. All actions of IL-1 identified to date appear to be mediated through its only known functional type I receptor (IL-1RI). However, our recent evidence suggests that some actions of IL-1 in the brain may be IL-1RI independent, suggesting the involvement of a new, hitherto unknown functional receptor for IL-1. 2. The objective of the present study was to determine if primary mixed glial cells express additional functional IL-1 receptors by studying the signalling mechanisms responsible for the pro-inflammatory actions of IL-1beta in cultures derived from IL-1RI-/- and wildtype mice, and to characterize the functional importance of IL-1 signalling pathways in glia. 3. IL-1beta induced marked release of IL-6 and prostaglandin-E(2) (PGE(2)) in the culture medium, and activated nuclear factor-kappa B (NFkappaB) and the mitogen-activated protein kinases (MAPK) p38, c-Jun N-terminal kinase (JNK) and the extracellular signal-regulated protein kinase (ERK1/2) in cells from wildtype mice. These responses were dependent on IL-1RI, since cells isolated from IL-1R1-/- mice did not demonstrate any of these responses. 4. In wildtype mice, inhibition of p38 or ERK1/2 MAPKs significantly reduced IL-1beta induced IL-6 release, whilst the NFkappaB inhibitor caffeic acid phenethyl ester (CAPE) modulated IL-1 induced IL-6 release by action on NFkappaB and MAPKs pathways. 5. These data demonstrate that IL-1RI is essential for IL-1beta signalling in cultured mixed glial cells. Thus IL-1 actions observed in IL-1RI-/- mice in vivo may occur via an alternative pathway and/or via different CNS cells.

Animals↗
PubMed2007

YC-1 inhibits HIF-1 expression in prostate cancer cells: contribution of Akt/NF-kappaB signaling to HIF-1alpha accumulation during hypoxia.

Hypoxia-inducible factor 1 (HIF-1), a transcription factor that is critical for tumor adaptation to microenvironmental stimuli, represents an attractive chemotherapeutic target. YC-1 is a novel antitumor agent that inhibits HIF-1 through previously unexplained mechanisms. In the present study, YC-1 was found to prevent HIF-1alpha and HIF-1beta accumulation in response to hypoxia or mitogen treatment in PC-3 prostate cancer cells. Neither HIF-1alpha protein half-life nor mRNA level was affected by YC-1. However, YC-1 was found to suppress the PI3K/Akt/mTOR/4E-BP pathway, which serves to regulate HIF-1alpha expression at the translational step. We demonstrated that YC-1 also inhibited hypoxia-induced activation of nuclear factor (NF)-kappaB, a downstream target of Akt. Two modulators of the Akt/NF-kappaB pathway, caffeic acid phenethyl ester and evodiamine, were observed to decrease HIF-1alpha expression. Additionally, overexpression of NF-kappaB partly reversed the ability of wortmannin to inhibit HIF-1alpha-dependent transcriptional activity, suggesting that NF-kappaB contributes to Akt-mediated HIF-1alpha accumulation during hypoxia. Overall, we identify a potential molecular mechanism whereby YC-1 serves to reduce HIF-1 expression.

Aryl Hydrocarbon Receptor Nuclear Translocator↗
PubMed2002

Speciation analysis of aluminium(III) in natural waters and biological fluids by complexing with various catechols followed by differential pulse voltammetry detection.

The biological effects of aluminium have received much attention in recent years. Speciation of Al is of basic relevance as it concerns its reactivity and bioavailability. A differential pulse voltammetry (DPV) procedure is proposed for speciation analysis of Al(III) in natural waters and biological fluids using six catechols (L-dopa, dopamine, epinephrine, norepinephrine, caffeic acid and o-benzenediol) as electroactive ligands. The decrease of the DPV anodic peak current for each catechol ligand is linear with the increase of Al concentration. This speciation analysis idea is based on the measurement of the complexation capacity, namely, different affinities of Al(III) for catechols and organic ligands under two pH conditions. The labile monomeric Al fraction (mainly inorganic aluminium) is determined at pH 4.6, while the total monomeric Al fraction is determined at pH 8.5. The principle for Al(III) speciation analysis by an electrochemical method is discussed. This sensitive and simple fractionation method is successfully applied to the speciation analysis of Al in natural waters and the results agree well with those of Driscoll's method. The speciation analysis of Al in biological fluids is also explored and the results are compared with those obtained by ultrafiltration and dialysis. Compared with other speciation protocols the electrochemical method possesses some remarkable advantages: rapidity, high sensitivity, cheap instrumentation and a simple operation procedure.

Aluminum↗
PubMed2005

Detection of reactive oxygen species in the skin of live mice and rats exposed to UVA light: a research review on chemiluminescence and trials for UVA protection.

The harmful effects of ultraviolet (UV) exposure on the skin are associated with the generation of reactive oxygen species (ROS) such as superoxide anion radical ( O(2)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radical ( OH), and singlet oxygen ((1)O(2)) as well as with lipid peroxides and their radicals (LOOH and LOO ). To give direct proof that such ROS are generated in UV-exposed skin, we proposed the in vivo detection and imaging method in which both a sensitive and specific chemiluminescence (CL) probe, such as CLA, and an ultralow-light imaging apparatus with a CCD camera were used. With this method we found that O(2)(-) is formed intrinsically and that (1)O(2) and O(2)(-) are generated in the UVA-exposed skin of mice. In addition, we indicated that antioxidative ability against ROS in the skin of hairless rats decreased as age increased. Using these findings, we demonstrated the protective abilities of sodium ascorbate, caffeic acid, essential aroma oils, and zinc(ii) ion and its complexes, which we administered to mice both topically and orally. We present a review for the current state of our research proposing the sensitive CL method as a useful in vivo tool in photobiological research for the detection of oxidative stress as well as for the evaluation of antioxidative agents to the skin.

Animals↗
PubMed1998

Cytotoxic effect of HIV-1 coat glycoprotein gp120 on human neuroblastoma CHP100 cells involves activation of the arachidonate cascade.

HIV type-1 (HIV-1) coat glycoprotein gp120 causes necrotic death in human neuroblastoma CHP100 cells. Here, we investigated the possible role of the arachidonate cascade and membrane peroxidation in gp120-induced cell necrosis. It is shown that gp120 increases the intracellular concentrations of prostaglandin E2 and leukotriene B4 by up-regulating the activity and expression of the arachidonate-metabolizing enzymes prostaglandin H synthase and 5-lipoxygenase respectively. Consistent with this observation, selective inhibitors of prostaglandin H synthase (i.e. indomethacin) and 5-lipoxygenase (i.e. MK886 and caffeic acid) protected CHP100 cells against gp120-induced necrosis. Treatment with gp120 also enhanced membrane lipid peroxidation and this may be implicated in the execution of cell damage. Interestingly, incubation with exogenous nitric oxide (NO) mimicked the effects of gp120 on necrotic death of CHP100 cells and activation of prostaglandin H synthase and 5-lipoxygenase. This suggests that NO might participate in the mechanism by which gp120 activates the arachidonate cascade.

Arachidonate 5-Lipoxygenase↗
PubMed2002

Isolation, cloning and expression of a multifunctional O-methyltransferase capable of forming 2,5-dimethyl-4-methoxy-3(2H)-furanone, one of the key aroma compounds in strawberry fruits.

Strawberry fruits contain an uncommon group of key aroma compounds with a 2,5-dimethyl-3(2H)-furanone structure. Here, we report on the methylation of 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) to 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMMF) by a S-adenosyl-L-methionine dependent O-methyltransferase, the cloning of the corresponding cDNA and characterization of the encoded protein. Northern-hybridization indicated that the Strawberry-OMT specific transcripts accumulated during ripening in strawberry fruits and were absent in root, petiole, leaf and flower. The protein was functionally expressed in E. coli and exhibited a substrate specificity for catechol, caffeic acid, protocatechuic aldehyde, caffeoyl CoA and DMHF. A common structural feature of the accepted substrates was a o-diphenolic structure also present in DMHF in its dienolic tautomer. FaOMT is active as a homodimer and the native enzyme shows optimum activity at pH 8.5 and 37 degrees C. It does not require a cofactor for enzymatic activity. Due to the expression pattern of FaOMT and the enzymatic activity in the different stages of fruit ripening we suppose that FaOMT is involved in lignification of the achenes and the vascular bundles in the expanding fruit. In addition, it is concluded that the Strawberry-OMT plays an important role in the biosynthesis of strawberry volatiles such as vanillin and DMMF.

Adenosine↗
PubMed2001

Down-regulation of occludin expression in astrocytes by tumour necrosis factor (TNF) is mediated via TNF type-1 receptor and nuclear factor-kappaB activation.

Tight junctions form the diffusion barrier of brain microcapillary endothelial cells and support cell polarity. Also astrocytes express tight junction components such as occludin, claudin-1, ZO-1 and ZO-2, but do not establish a permeability barrier. However, little is known about the function and regulation of these molecules in astrocytes. We studied the impact of tumour necrosis factor (TNF) on occludin and ZO-1 expression in astrocytes. TNF decreased occludin, but not ZO-1 expression. In brain microcapillary endothelial cells, as well as in epithelial cells, occludin expression was not influenced by TNF. Removal of TNF from astrocytes restored the basal level of occludin. Down-regulation was inhibited by caffeic acid phenethyl ester, a specific inhibitor of nuclear factor-kappaB (NF-kappaB) activation. Exposure of astrocytes isolated from mice deficient in either TNF type-1 receptor (TNFR1), TNF type-2 receptor (TNFR2), or both, respectively, revealed that down-regulation was mediated entirely by TNFR1. ZO-1, which can interact with occludin, was found to co-precipitate connexin43, but not occludin. These findings demonstrate that TNF selectively down-regulates occludin in astrocytes, but not in cells forming established tight junctions, through TNFR1 and suggest that NF-kappaB is involved as a negative regulator.

Animals↗
PubMed2003

Interleukin-1beta stimulates macrophage inflammatory protein-1alpha and -1beta expression in human neuronal cells (NT2-N).

Chemokines are important mediators in immune responses and inflammatory processes of neuroimmunologic and infectious diseases. Although chemokines are expressed predominantly by cells of the immune system, neurons also express chemokines and chemokine receptors. We report herein that human neuronal cells (NT2-N) produce macrophage inflammatory protein-1alpha and -1beta (MIP-1alpha and MIP-1beta), which could be enhanced by interleukin (IL)-1beta at both mRNA and protein levels. The addition of supernatants from human peripheral blood monocyte-derived macrophage (MDM) cultures induced MIP-1beta mRNA expression in NT2-N cells. Anti-IL-1beta antibody removed most, but not all, of the MDM culture supernatant-induced MIP-1beta mRNA expression in NT2-N cells, suggesting that IL-1beta in the MDM culture supernatants is a major factor in the induction of MIP-1beta expression. Investigation of the mechanism(s) responsible for IL-1beta-induced MIP-1alpha and -1beta expression demonstrated that IL-1beta activated nuclear factor kappa B (NF-kappaB) promoter-directed luciferase activity in NT2-N cells. Caffeic acid phenethyl ester, a potent and specific inhibitor of activation of NF-kappaB, not only blocked IL-1beta-induced activation of the NF-kappaB promoter but also decreased IL-1beta-induced MIP-1alpha and -1beta expression in NT2-N cells. These data suggest that NF-kappaB is at least partially involved in the IL-1beta-mediated action on MIP-1alpha and -1beta in NT2-N cells. IL-1beta-mediated up-regulation of beta-chemokine expression may have important implications in the immunopathogenesis of inflammatory diseases in the CNS.

Cell Line↗
PubMed2003

A clinical pharmacological study of the potential beneficial effects of a propolis food product as an adjuvant in asthmatic patients.

The aqueous extract of propolis has been formulated as a nutritional food product and administered, as an adjuvant to therapy, to patients with mild to moderate asthma daily for 2 months in the framework of a comparative clinical study in parallel with a placebo preparation. The diagnosis of asthma was made according to the criteria of patient classification of the National Institutes of Health and Global Initiative for Asthma Management. At inclusion, the pulmonary forced expiratory volume in the first second (FEV1) as a percentage of the forced vital capacity (FVC) was more than 80% in mild persistent cases, and between 60 and 80% in moderate persistent cases, showing an increase in the degree of reversibility of > 15% in FEV1. All patients were on oral theophylline as controller therapy, none was receiving oral or inhaled corticosteroids, none had other comorbidities necessitating medical treatment, and all were from a middle-class community and had suffered from asthma for the last 2-5 years. Twenty-four patients received the placebo, with one drop-out during the study, while 22 received the propolis extract, with no drop-outs. The age range of the patients was 19-52 years; 36 were male and 10 female. The number of nocturnal attacks was recorded on a weekly basis, while pulmonary function tests were performed on all patients at the beginning of the trial, 1 month later and at the termination of the trial. Immunological parameters, including various cytokines and eicosanoids known to play a role in asthma, were measured in all patients at the beginning of the trial and 2 months later. Analysis of the results at the end of the clinical study revealed that patients receiving propolis showed a marked reduction in the incidence and severity of nocturnal attacks and improvement of ventilatory functions. The number of nocturnal attacks dropped from an average of 2.5 attacks per week to only 1. The improvement in pulmonary functions was manifested as a nearly 19% increase in FVC, a 29.5% increase in FEV1, a 30% increase in peak expiratory flow rate (PEFR), and a 41% increase in the forced expiratory flow rate between 25 and 75% of the vital capacity (FEF25-75). The clinical improvement was associated with decreases by 52, 65, 44 and 30%, respectively, of initial values for the pro-inflammatory cytokines tumor necrosis factor (TNF)-alpha, ICAM-1, interleukin (IL)-6 and IL-8, and a 3-fold increase in the 'protective' cytokine IL-10. The levels of prostaglandins E2 and F2alpha and leukotriene D4 were decreased significantly to 36, 39, and 28%, respectively, of initial values. Patients on the placebo preparation showed no significant improvement in ventilatory functions or in the levels of mediators. The findings suggest that the aqueous propolis extract tested is potentially effective as an adjuvant to therapy in asthmatic patients. The benefits may be related to the presence in the extract of caffeic acid derivatives and other active constituents.

Adult↗
PubMed2003

Alcohol potentiates hepatitis C virus replicon expression.

Alcohol consumption accelerates liver damage and diminishes the anti-hepatitis C virus (HCV) effect of interferon alfa (IFN-alpha) in patients with HCV infection. It is unknown, however, whether alcohol enhances HCV replication and promotes HCV disease progression. The availability of the HCV replicon containing hepatic cells has provided a unique opportunity to investigate the interaction between alcohol and HCV replicon expression. We determined whether alcohol enhances HCV RNA expression in the replicon containing hepatic cells. Alcohol, in a concentration-dependent fashion, significantly increased HCV replicon expression. Alcohol also compromised the anti-HCV effect of IFN-alpha. Investigation of the mechanism(s) responsible for the alcohol action on HCV replicon indicated that alcohol activated nuclear factor kappaB (NF-kappaB) promoter. Caffeic acid phenethyl ester (CAPE), a specific inhibitor of the activation of NF-kappaB, abolished alcohol-induced HCV RNA expression. In addition, naltrexone, an opiate receptor antagonist, abrogated the enhancing effect of alcohol on HCV replicon expression. In conclusion, alcohol, probably through the activation of NF-kappaB and the endogenous opioid system, enhances HCV replicon expression and compromises the anti-HCV effect of IFN-alpha. Thus, alcohol may play an important role in vivo as a cofactor in HCV disease progression and compromise IFN-alpha-based therapy against HCV infection.

Antidotes↗
PubMed2001

Inhibitory effect of decoction of Perilla frutescens on cultured murine mesangial cell proliferation and quantitative analysis of its active constituents.

The leaves of Perilla frutescens (perilla) are a common herb used in Japan for garnishing raw seafood. Previously, we reported that a decoction of perilla leaves had suppressive effects on the progression of glomerulonephritis in an animal model of spontaneous IgA nephropathy. The objective of the present study was to isolate anti-nephritic constituents in the perilla decoction under the guidance of its in vitro anti-proliferative activity on cultured murine mesangial cells, and to measure the contents of the active constituents in decoctions prepared from various perilla chemotypes, which differ in their composition of essential oils and/or pigments. DNA synthesis of cultured mesangial cells induced by 1% fetal calf serum was significantly inhibited by the perilla decoction (IC50 values, 8.8 microg/ml). Caffeic acid, luteolin 7-O-[beta-glucuronosyl(1-->2)beta-glucuronide], apigenin 7-O-[beta-glucuronosyl(1-->2)beta-glucuronide], scutellarin, and rosmarinic acid were isolated as active constituents. The contents of these phenolic compounds were not significantly different among chemotypes of P. frutescens. Considering the relation between the contents in the perilla decoction and the activities of these compounds, rosmarinic acid represents the in vitro anti-proliferative effect of perilla decoction.

Animals↗
PubMed2003

Diterpenes from the aerial parts of Salvia candelabrum and their protective effects against lipid peroxidation.

A methanolic extract of the aerial parts of Salvia candelabrum was subjected to multiple chromatographic separation under the guidance of anti-lipid peroxidation assay. From the most active fractions seven abietane and seco-abietane diterpenes were isolated by preparative TLC purification. Besides candesalvoquinone, candelabroquinone, 12- O-methylcandesalvone B, candesalvone B methyl ester and candelabrone (all reported earlier), the known candesalvone B and the new candesalvolactone were identified. The structures were established by means of mass spectroscopy and advanced 2D NMR methods. All the identified compounds were evaluated for antioxidant activity in enzyme-dependent (IC (50) values 3.49 - 10.42 microM) and enzyme-independent (IC (50) values 1.40 - 13.40 microM) systems of lipid peroxidation. All compounds displayed marked concentration-dependent effects in both tests as compared with those of authentic ascorbic, rosmarinic and caffeic acids. The differences in antioxidant capacities observed in the enzyme-independent system allowed conclusions concerning structure-activity relationships.

Antioxidants↗
PubMed2004

Cinnamaldehyde and 2-methoxycinnamaldehyde as NF-kappaB inhibitors from Cinnamomum cassia.

Nuclear factor (NF)-cB is a transcription factor regulating the expression of inflammatory and immune genes. In the present study, an extract from stem bark of Cinnamomum cassia Blume(Lauraceae) was discovered to have an inhibitory effect on LPS-induced NF-KB transcriptional activity, which was determined using macrophages RAW 264.7 transfected stably with an alkaline phosphatase reporter construct containing four copies of the NF-KB binding KB sequence. Following activity-guided fractionation, trans-cinnamaldehyde and 2-methoxycinnamaldehyde were identified as the NF-KB inhibitors from C cassia with IC50 values of 43 MM and 31 pM, respectively. As a positive control, caffeic acid phenethyl ester (CAPE) showed an IC50 value of 2 uM on NF-KB transcriptional activity. Both trans-cinnamaldehyde and 2-methoxycinnamaldehyde inhibited LPS-induced DNA binding activity of NF-KB in addition to NF-KB transcription-al activity.

Acrolein↗
PubMed2005

Transcriptome analysis of ozone-responsive genes in leaves of European beech (Fagus sylvatica L.).

Suppression subtractive hybridization (SSH) was performed to isolate cDNAs representing genes that are differentially expressed in leaves of Fagus sylvatica upon ozone exposure. 1248 expressed sequence tags (ESTs) were obtained from 2 subtractive libraries containing early and late ozone-responsive genes. Sequences of 1139 clones (91 %) matched the EBI/NCBI database entries. For 578 clones, no putative function could be assigned. Most abundant transcripts were O-methyltransferases, representing 7 % of all sequenced clones. ESTs were organized into 12 functional categories according to the MIPS database. Among them, 12 % (early)/15 % (late) were associated with disease and defence, 19/11 % with cell structure, 4/10 % with signal transduction, and 9/6 % with transcription. The expression pattern of selected ESTs (ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit [rbcS], WRKY-type transcription factor, ultraviolet-B-repressible protein, aquaporine, glutathione S-transferase, catalase, caffeic acid O-methyltransferase, and pathogenesis-related protein 1 [PR1]) was analysed by quantitative real-time RT-PCR (qRT-PCR) which confirmed changed transcript levels upon ozone treatment of European beech saplings. The ESTs characterized will contribute to a better understanding of forest tree genomics and also to a comparison of ozone-responsive genes in woody and herbaceous plants.

Europe↗