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1.
为了解降龙草(Hemiboea subcapitata Clarke)的化学成分,从降龙草全草的乙醇提取物的石油醚和乙酸乙酯萃取部位分离得到了5个蒽醌类化合物。经波谱学分析鉴定为digiferruginol(1)、1,4-二羟基-2-羟甲基-9,10-蒽醌(2)、1,7-二羟基-2-羟甲基-9,10-蒽醌(3)、1-羟基-7-甲氧基-2-羟甲基-9,10-蒽醌(4)和1,4,7-三羟基-2-甲基-9,10-蒽醌(5)。其中化合物4和5为新化合物,其它3个化合物为首次从降龙草中分离得到。 相似文献
2.
Friedrich N. Burnett Ramachandra S. Hosmane 《Nucleosides, nucleotides & nucleic acids》2013,32(3-5):325-328
Abstract The attempted ring-closure of 4-amino-1-benzyl-5-[(N2-benzyl-N2-methoxy-carbonyl)hydrazinomethylenecarbonyl]imidazole (5b) in sodium hydride/dimethyl sulfoxide at 50–60 °C afforded 1,7-dibenzylxanthine (6) instead of the anticipated 5:8-fused heterocycle 4b. A tentative reaction pathway has been proposed for the observed transformation. 相似文献
3.
Lucia Rišiaňová Eva Fischer-Fodor Jindra Valentová Corina Tatomir Nicoleta Corina Decea Piroska Virag Iveta Pechová Ferdinand Devínsky Natalia Miklášová 《Bioorganic & medicinal chemistry letters》2017,27(11):2345-2349
Biologically active Knoevenagel condensates (1–14) of diarylheptanoids: 1,7-bis(3-methoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione and 1,7-bis(3-ethoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione, were synthesized and structurally characterized. Compounds 1–14 exhibited cytotoxicity against colon carcinoma cells, and their antiproliferative effect was associated with a significant decrease of multidrug resistance proteins. One of the underlying mechanisms of these effects is the reduction of intracellular and extracellular SOD enzymes by compounds 1, 12 and 14, which render the tumor cells more vulnerable to oxidative stress. 相似文献
4.
Nicoletta Guaragnella Antonella Bobba Ersilia Marra Sergio Giannattasio 《FEBS letters》2010,584(1):224-228
To investigate the role of cytochrome c (cyt c) release in yeast acetic acid-induced programmed cell death (AA-PCD), wild type (wt) and cells lacking metacaspase (Δyca1), cytochrome c (Δcyc1,7) and both (Δcyc1,7Δyca1) were compared for AA-PCD occurrence, hydrogen peroxide (H2O2) production and caspase activity. AA-PCD occurs in Δcyc1,7 and Δcyc1,7Δyca1 cells slower than in wt, but similar to that in Δyca1 cells, in which no cytochrome c release occurs. Both H2O2 production and caspase activation occur in these cells with early and extra-activation in Δcyc1,7 cells. We conclude that alternative death pathways can be activated in yeast AA-PCD, one dependent on cyt c release, which requires YCA1, and the other(s) independent on it. 相似文献
5.
James W. Atkinson 《Invertebrate reproduction & development.》2013,57(2):169-178
Summary The olive fruit fly, Dacus oleae, female incorporated dietary 14 C-labeled malonate, succinate, glutamate, and propionate into the primary pheromone component, 1,7-dioxaspiro[5,5]undecane (1); but did not significantly incorporate acetate. Explanted pheromone glands when incubated in pH 7 phosphate buffer with [14C]malonate incorporated the label into 1, but did not incorporate [14C]glutamate. Incorporation of labeled malonate by incubating explanted glands was temperature and age dependent. 相似文献
6.
《Bioscience, biotechnology, and biochemistry》2013,77(7):1618-1622
Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produce a novel sex pheromone composed of three methyl-branched ketones (I–III) in a ratio of 2:1:1. In order to confirm the structure of III (6,14-dimethyl-2-octadecanone), a mixture of its four stereoisomers was synthesized via chain elongation by two Wittig reactions, starting from 1,7-hexanediol. GC-MS data of the synthetic III were satisfactorily coincident with those of the natural component. In addition to the racemic mixtures of I (6-methyl-2-octadecanone) and II (14-methyl-2-octadecanone), previously synthesized, the activity of III was evaluated in the Iriomote Islands, and effective male attraction was observed for the 2:1:1 mixture of I–III. This result indicates that the females do not produce only one stereoisomer for each component or that the response of the males is not disturbed by the other stereoisomers of natural isomers produced by the females. The field test also revealed that the two-component lure of I and II captured as many males as the mixture of I–III, while lures baited with two components in other combinations and with only one component scarcely exhibited any male attraction ability. 相似文献
7.
Tokumi Maruyama Shigetada Kozai Fumi Sasaki 《Nucleosides, nucleotides & nucleic acids》2013,32(7):1193-1203
Abstract A general procedure to obtain tetra-substituted uric acid by stepwise N-alkylation is described. 2,6-Dichloropurine (1) was condensed with 1-propanol by Mitsunobu reaction to give 9-propyl congener (2). Treatment of 2 with ammonia gave adenine derivative (4a), which was converted to the 8-oxoadenine (5b) in 3 steps. Methylation of 5b proceeded site-specifically to give 6-amino-2-chloro-7,8-dihydro-7-methyl-9-propylpurin-8-one (6) as a sole product. Compound 6 was successively treated with NaNO2 and iodomethane to give 2-chloro-1,6,7,8-tetrahydro-1,7-dimethyl-9-propylpurin-6,8-dione (9) accompanied by the O 6-methyl product (8) in 75% and 6.9%, respectively. After nucleophilic substitution of 9 with NaOAc, the product (11) was reacted with iodomethane to give the uric acid (12) and the 2-methoxy product (13) in 46% and 15.5%, respectively. However, the reaction of 11 with the benzylating agents gave only O-benzyl products (14a,b). 相似文献
8.
Darja Kanduc 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1982,697(3):336-343
tRNA chemical methylation: 1. 1,7-Dimethylguanosine was found in in vivo methylated tRNA from liver and kidney of rat after exposure to a low dose of dimethylnitrosamine (4 mg/kg body weight). 2. At 4 h after dimethylnitrosamine administration, the 1,7-dimethylguanosine:7-methylguanine ratio (product ratio) for liver and kidney tRNA was 0.017 and 0.091, respectively. At 24 h after dimethylnitrosamine administration, the product ratio was lower in both hepatic and renal tRNA. 3. When dimethylnitrosamine was given in four separate daily injections, the product ratio in hepatic tRNA 4 h after the last dose was the same as for the same total dose given by a single injection, but in renal tRNA it was lower. No dialkyl compound was found in liver and kidney tRNA 24 h after the last multiple injection. tRNA enzymatic methylation: 1. Base analyses of Escherichia coli B tRNA methylated in vitro, by using S-adenosylmethionine as physiological methyl donor and enzyme preparations from liver and kidney of normal rat, indicated that 1,7-dimethylguanosine was also a product of enzymatic methylation. 2. The amount of 1,7-dimethylguanosine formed by kidney enzyme preparation was 3-times that produced by the liver extract. 3. A second type of enzymatic methylation assay where chemically methylated tRNA was used as substrate indicated that the 7-methylguanosine residues in the nucleic acid are not the substrate of the methylase activity forming the 1,7-dimethylguanosine moieties. Analogous data were obtained for the origin of 1,7-dimethylguanosine residues in tRNA chemical methylation by dimethyl sulphate. 相似文献
9.
The 8-hydroxy derivative of adenine (6-amino-1,7-dihydro-8H-purin-8-one) is produced from adenine by two Oerskovia xanthineolytica strains. This transformation by a microorganism has not been reported previously. No novel products of dissimilation of xanthine (3,7-dihydro-1H-purine-2,6-dione) or hypoxanthine (1,7-dihydro-6H-purin-6-one) were found. Xanthine was oxidized to uric acid, but intermediates in the breakdown of hypoxanthine could not be demonstrated. 相似文献
10.
Seven 1-hydroxyxanthones have been isolated from the roots of Frasera albomarginata. There were 1-hydroxy-3,7-dimethoxy-, 1-hydroxy-3,5-dimethoxy-, 1,8-dihydroxy-3,5-dimethoxy-, 1-hydroxy-2,3,4,7-tetramethoxy-, 1-hydroxy-2,3,4,5-tetramethoxy-, 1-hydroxy-3,4,7-trimethoxy- and 1-hydroxy-2,3,5-trimethoxyxanthone. Six 1-hydroxyxanthones were obtained from the roots of F. speciosa. These were 1-hydroxy-2,3,4,5-tetramethoxy-, 1-hydroxy-2,3,4,7-tetramethoxy-, 1-hydroxy-2,3,5-trimethoxy-, 1,7-dihydroxy-2,3,4-trimethoxy-, 1,7-dihydroxy-2,3-dimethoxy- and 1,3-dihydroxy-4,5-dimethoxyxanthone. 相似文献
11.
Activation of wheat chloroplast sedoheptulose bisphosphatase: a continuous spectrophotometric assay 总被引:3,自引:0,他引:3
A new continuous spectrophotometric assay for sedoheptulose 1,7-bisphosphatase, applied to studies of the activation and steady-state kinetics of the wheat enzyme, is described. The assay enzyme sequence couples the formation of sedoheptulose 7-phosphate to the oxidation of NADH. The recycling of the reaction substrate enables measurements to be made at essentially constant substrate concentrations. Activation of wheat chloroplast sedoheptulose 1,7-bisphosphatase required a reducing agent and could be described by a first-order rate constant. The rate of activation was greatly increased in the presence of Mg2+ and sedoheptulose 1,7-bisphosphate. The Km of the activated enzyme for sedoheptulose 1,7-bisphosphate. and its S0.5 for Mg2+ were found to be 13.3 μm and 1.6 mm respectively. A high recovery method for purifying wheat chloroplast sedoheptulose 1,7-bisphosphatase is also detailed. 相似文献
12.
《Cell biology international reports》1989,13(1):129-136
Caffeine and some related compounds are known to inhibit cell plate formation (CPF), but little is known about their mechanism of action. In this connection, the effects of xanthine derivatives on CPF in Tradescantia stamen hair cells were examined. Caffeine (1,3,7-trimethylxanthine) and 1,3-dimethyl-xanthine were more effective inhibitors of CPF than 1-methyl- or 1,7-dimethyl-xanthine. Four compounds with a substituent at the three position of 1,7-dimethyl-xanthine were found to be more effective than caffeine as inhibitors of CPF. Among them, 1,7-dimethyl-3-(3-ethylbutyl) xanthine was the most effective and the concentration required for inhibition of CBF was one tenth of that of caffeine. Breakdown of cell plates could be partially reversed using guanosine or adenosine, but reversibility was not detected using cytokinins. 相似文献
13.
《Phytomedicine》2010,17(12):1144-1150
In this study, six major xanthones, isolated and identified from Halenia elliptica were investigated for their vasodilatory actions in isolated rat coronary artery. The xanthones, including 1-hydroxy-2,3,5-trimethoxy-xanthone (HM-1), 1-hydroxy-2,3,4,7-tetramethoxy-xanthone (HM-2), 1-hydroxy-2,3,4,5-tetramethoxy-xanthone (HM-3), 1,7-dihydroxy–2,3,4,5-tetramethoxy-xanthone (HM-4), 1,5-dihydroxy-2,3-dimethoxy-xanthone (HM-5) and 1,7-dihydroxy-2,3-dimethoxy-xanthone (HM-7) caused vasodilation in the coronary artery pre-contracted with 1 μM 5-hydroxytryptamine (5-HT), with EC50 values ranging from 1.4±0.1 μM (HM-1) to 6.6±1.4 μM (HM-2). The EC50 values of the other xanthones were between those of HM-1 and HM-2. Removal of endothelium of the coronary artery led to decreases in the vasorelaxant effects of HM-1, HM-7 but not HM-2, HM-3, HM-4 and HM-5. Our results showed that xanthones isolated from Halenia elliptica are vasoactive substances which exhibit either endothelium-dependent or endothelium-independent mechanisms in rat coronary artery. The potency and mechanism(s) of the vasorelaxant effects of these xanthones may be relevant to the structure–activity differences in the level and the position of the substituent groups with the primary xanthone structure. 相似文献
14.
15.
Yan Wang Jian-Gong Shi Mu-Zou Wang Chun-Tao Che John H.K. Yeung 《Phytomedicine》2009,16(12):1144-1150
In this study, six major xanthones, isolated and identified from Halenia elliptica were investigated for their vasodilatory actions in isolated rat coronary artery. The xanthones, including 1-hydroxy-2,3,5-trimethoxy-xanthone (HM-1), 1-hydroxy-2,3,4,7-tetramethoxy-xanthone (HM-2), 1-hydroxy-2,3,4,5-tetramethoxy-xanthone (HM-3), 1,7-dihydroxy–2,3,4,5-tetramethoxy-xanthone (HM-4), 1,5-dihydroxy-2,3-dimethoxy-xanthone (HM-5) and 1,7-dihydroxy-2,3-dimethoxy-xanthone (HM-7) caused vasodilation in the coronary artery pre-contracted with 1 μM 5-hydroxytryptamine (5-HT), with EC50 values ranging from 1.4±0.1 μM (HM-1) to 6.6±1.4 μM (HM-2). The EC50 values of the other xanthones were between those of HM-1 and HM-2. Removal of endothelium of the coronary artery led to decreases in the vasorelaxant effects of HM-1, HM-7 but not HM-2, HM-3, HM-4 and HM-5. Our results showed that xanthones isolated from Halenia elliptica are vasoactive substances which exhibit either endothelium-dependent or endothelium-independent mechanisms in rat coronary artery. The potency and mechanism(s) of the vasorelaxant effects of these xanthones may be relevant to the structure–activity differences in the level and the position of the substituent groups with the primary xanthone structure. 相似文献
16.
Yoshiko Iwasaki Kazuo Chihara Junji Iwasaki Hiromi Abe Takuo Fujita 《Life sciences》1979,25(14):1243-1248
Injection of [Asu1,7]-eel calcitonin (CT) (0.1–2.5μg) into the lateral ventricle resulted in a significant and dose-related increase of plasma prolactin (PRL) levels in urethane-anesthetized male rats. Naloxone failed to block [Asu1,7]-eel CT induced PRL release. Salmon CT, human CT and porcine CT were similarly effective to stimulate PRL release when injected intraventricularly. Intravenous administration of [Asu1,7]-eel CT(20 μg) failed to cause any significant changes in plasma PRL levels, while this peptide (10?8?10?6M) possesed a mild stimulating activity of PRL release from the anterior pituitary cells cultured . These results suggest that CT stimulates rat PRL secretion mainly through the central nervous system like one of the neurotransmitters, though it may also act directly on the pituitary. 相似文献
17.
Using partially purified sedoheptulose-1,7-bisphosphatase from spinach (Spinacia oleracea L.) chloroplasts the effects of metabolites on the dithiothreitoland Mg2+-activated enzyme were investigated. A screening of most of the intermediates of the Calvin cycle and the photorespiratory pathway showed that physiological concentrations of sedoheptulose-7-phosphate and glycerate specifically inhibited the enzyme by decreasing its maximal velocity. An inhibition by ribulose-1,5-bisphosphate was also found. The inhibitory effect of sedoheptulose-7-phosphate on the enzyme is discussed in terms of allowing a control of sedoheptulose-1,7-bisphosphate hydrolysis by the demand of the product of this reaction. Subsequent studies with partially purified fructose-1,6-bisphosphatase from spinach chloroplasts showed that glycerate also inhibited this enzyme. With isolated chloroplasts, glycerate was found to inhibit CO2 fixation by blocking the stromal fructose-1,6-bisphosphatase. It is therefore possible that the inhibition of the two phosphatases by glycerate is an important regulatory factor for adjusting the activity of the Calvin cycle to the ATP supply by the light reaction.Abbreviations DTT
dithiothreitol
- FBPase
fructose-1,6-bisphosphatase
- Fru-1,6-P2
fructose-1,6-bisphosphate
- Fru-6-P
fructose-6-phosphate
- 3-PGA
3-phosphoglycerate
- Ru-1,5-P2
ribulose-1,5-bisphosphate
- Ru-5-P
ribulose-5-phosphate
- SBPase
sedoheptulose-1,7-bisphosphatase
- Sed-1,7-P2
sedoheptulose-1,7-bisphosphate
- Sed-7-P
sedoheptulose-7-phosphate
This work was supported by the Deutsche Forschungsgemein-schaft. 相似文献
18.
Susanne Rumich-Bayer Christoph Giersch G. Heinrich Krause 《Photosynthesis research》1987,14(2):137-145
Isolated mesophyll protoplasts from Valerianella locusta L. were subjected to freeze-thaw cycles. Subsequently, steady-state pool sizes of 14C-labeled intermediates of the photosynthetic carbon reduction cycle were determined by high performance liquid chromatography. Protoplasts in which CO2 fixation was inhibited by preceding freezing stress, showed a strong increase in the proportion of fructose-1,6-bisphosphate, sedoheptulose-1,7-bisphosphate and triose phosphates. These results indicate an inhibition of the activities of stromal fructose-1,6-bisphosphatase and sedoheptulose-1,7-bisphosphatase. Furthermore, freezing stress caused a slight increase in the proportion of labeled ribulose-1,5-bisphosphate, which may be based on an inhibition or ribulose bisphosphate carboxylase activity. It was shown earlier (Rumich-Bayer and Krause 1986) that freezing-thawing readily affects photosynthetic CO2 assimilation independently of thylakoid inactivation. The present results are interpreted in terms of an inhibition of the light-activation system of the photosynthetic carbon reduction cycle, caused by freezing stress.Abbreviations FBP
Fructose-1,6-bisphosphate
- HMP
Hexose Monophosphates
- PGA
3-phosphoglycerate
- PMP
Pentose Monophosphates
- RBP
Ribulose-1,5-bisphosphate
- SBP
Sedoheptulose-1,7-bisphosphate
- TP
Triose Phosphates 相似文献
19.
Wanderley G. De Oliveira Antonio A. Lins Mesquita Roberto A. De Lima Otto R. Gotllieb Hugo E. Gotllieb 《Phytochemistry》1984,23(10):2390-2391
The trunk wood of Tovomita excelsa (Guttiferae) from north-eastern Brazil contains, besides betulinic acid, 1,5-dihydroxy-6-methoxyxanthone, 1,6-dihydroxy-5-methoxyxanthone, 5,6-dihydroxy-1-methoxyxanthone and 1,7- dihydroxy-6-methoxyxanthone. 相似文献
20.
Kenji Mori Masanao Matsui Yusuke Sumiki 《Bioscience, biotechnology, and biochemistry》2013,77(3):179-183
Degradation of gibberellin C afforded methyl 1,7-dimethyl-2α-hydroxy-8-oxo-7α-gibb-4a(4b)-ene-1,10-dicarboxylate, from which gibberellin C was reconstructed. Reactions of desoxogibberellin C are also described. 相似文献