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91.
Screening tests are described for the development of chemiluminescence systems (oxidizing systems) capable of detecting biological organic compounds. The light emission depends strongly on the oxidizing systems employed. Acidic permanganate system gives rise to light emission for many compounds, including catechols, catecholamines, triphenols and indoles. The following oxidizing systems led specifically to chemiluminescence for hydroquinone, adrenaline or phenylpyruvic acid: 10?1 M thiosulphate with 10?1 M sodium hydroxide and 10?4 M Ag (I), 0.3 % hydrogen peroxide with 10?3 M sodium hydroxide/50% acetonitrile and 10?4 M Fe (II), and 0.3% hydrogen peroxide with 10?2 M sodium hydroxide/10?2 M didodecyldimethylammonium bromide and 10?4 M Co(II), respectively. 相似文献
92.
Isolation of inhibitors of adenylate cyclase from dan-shen, the root of Salvia miltiorrhiza 总被引:3,自引:0,他引:3
H Kohda O Takeda S Tanaka K Yamasaki A Yamashita T Kurokawa S Ishibashi 《Chemical & pharmaceutical bulletin》1989,37(5):1287-1290
The effect of dan-shen extract, the root of Salvia miltiorrhiza, on adenylate cyclase was investigated in both rat brain and rat erythrocytes. The EtOAc fraction of the MeOH extract was proved to have significant inhibitory activity. Potent inhibitory principles in the EtOAc fraction were isolated and identified as 4 polyphenolic acids, rosemarinic acid, lithospermic acid, and their methyl ester derivatives. 相似文献
93.
Screening for molluscicidal activity in crude drugs 总被引:1,自引:0,他引:1
O Takeda S Tanaka K Yamasaki H Kohda Y Iwanaga M Tsuji 《Chemical & pharmaceutical bulletin》1989,37(4):1090-1091
Thirty-four extracts of crude drugs and medicinal plants have been screened for activity against Oncomelania nosophora, the intermediate host of the Japanese strain of Schistosoma japonicum. Strong molluscicidal activity was found in the MeOH extract of Anemarrhenae Rhizoma. Although timosaponin A-III, one of the main saponins of Anemarrhenae Rhizoma, showed very strong killing activity, markogenin-3-O-beta-D-glucopyranosyl (1-2)-O-beta-D-galactopyranoside having the same glycosidic linkage was found to be inactive. 相似文献
94.
Tsumoto H Murata C Miyata N Taguchi R Kohda K 《Chemical & pharmaceutical bulletin》2003,51(12):1399-1401
Methyl groups of 6-methylnicotinic acid and 2,6-dimethylnicotinic acid were deuterated by an H-D exchange reaction under conditions of 1% NaOD/D(2)O on heating. With a condensation reaction between the D-labeled nicotinic acid derivative and N-hydroxysuccinimide with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, the nicotinoylating agents, 1-(6-methyl[D(3)]nicotinoyloxy)succinimide (2c) and 1-(2,6-dimethyl[D(6)]nicotinoyloxy)succinimide (2f) were prepared. Both D-labeled nicotinoylating agents and their unlabeled counterparts quantitatively modified the N-terminal of protein. 相似文献
95.
I Kohda H Nagai M Iwai M Watanabe K Yokoyama K Tsujikawa T Mimura 《Chemical & pharmaceutical bulletin》1991,39(7):1828-1831
The effects of 2-(E-2-decenoylamino)ethyl 2-(cyclohexylethyl) sulfide (compd. III-1a) on various experimental ulcers were investigated. The oral administration of compd. III-1a at doses ranging from 30 to 300 mg/kg inhibited the acute gastric ulcerations induced by ethanol, HCl.aspirin and indomethacin in rats. Compound III-1a significantly inhibited the water immersion stress-induced gastric ulcer at doses of 3 mg/kg, p.o. The anti-ulcer activity of plaunotol as a reference drug was equivalent on an ethanol-induced ulcer to that of compd. III-1a, but weaker on HCl.aspirin, indomethacin and stress-induced ulcers than that of compd. III-1a. On indomethacin-produced gastric antral ulcer, compd. III-1a showed the same significant inhibitory activity as spizofurone did at a dose of 100 mg/kg, p.o. Compound III-1a also inhibited hemorrhagic shock-, diethyldithiocarbamic acid (DDC)-and platelet activating factor (PAF)-induced ulcers dose-dependently. Plaunotol only showed significant inhibitory activity on PAF-induced ulcer in these three ucler models. The consecutive administration of compd. III-1a (100 mg/kg, p.o.) twice a day significantly accelerated the healing of an acetic acid-induced ulcer and that of plaunotol (200 mg/kg, p.o.) showed the same activity. Moreover, orally administered compd. III-1a at a dose of 100 mg/kg decreased the gastric acid secretion in pylorus-ligated rats. The results in the present study suggest that compd. III-1a has the dual action on ulcer formation. 相似文献
96.
Flow injection analysis, with chemiluminescence detection, is used to determine traces of cobalt(II) by means of the gallic acid—hydrogen peroxide—sodium hydroxide system containing a small amount of methanol to increase the sensitivity. This permits the determination of cobalt(II) more selectively than any other chemiluminescent system with a detection limit of 0.04 μg l-1 (continuous sample flow) or 0.04 ng (10-μl sample injection). The linear range is 3 orders of magnitude, the sampling rate is 20 h-1, and the relative standard deviation is 5.9% for 0.06 ng Co(II) (n = 10). Silver(I), the strongest enhancer after cobalt(II), provides a signal 1.3% of that for Co(II). A few precipitants and complexing agents suppress the signal. 相似文献
97.
Shigetaka Fukuda 《Geometriae Dedicata》2001,85(1-3):183-187
We prove that every log crepant birational morphism between log terminal surfaces can be decomposed into log flopping type divisorial contraction morphisms and log blowdowns. Repeating these two kinds of contractions, we reach a minimal log minimal surface from any log minimal surface. 相似文献
98.
Hydrogen fluoride in a standard or sample gas stream at 200 ml min?1 permeates through a teflon membrane (0.8 μm pore size, 0.08 mm thick) into an absorption solution (citrate/acetate buffer at pH 5.4) flowing at 30 ml min?1. The fluoride produced is measured with the fluoride-selective electrode. The response time is about 12 min. The absorption efficiency of hydrogen fluoride is about 70% between 6.5 and 0.25 ppm by volume (5.2 and 0.2 mg m?3). In this range, the Nernst equation is valid with a relative standard deviation of less than 1.8%. The lower determination limit for hydrogen fluoride is 0.1 ppm (0.08 mg m?3). 相似文献
99.
Isamu Maeba Masahiko Ando Shigetaka Yoshina Raymond N. Castle 《Journal of heterocyclic chemistry》1979,16(2):245-247
The reaction of 4,7-diehlorofuro[2,3-d]pyridazine (1) with potassium cyanide in DMSO gave two products, (E)-3,6-diehloro-5-(2-cyanovinyl)-4-hydroxypyridazine (II) and 5,8-dichloro-2-oxo-2H-pyrano[2,3-d]pyridazine (III) as a result of ring opening or ring expansion. A new ring system, 2-oxo-2H-pyrano[2,3-c]pyridazines (IX, XII, XIII) was obtained from 5,8-dichloro-3-methyl-2-oxo-2H-pyrano[2,3-d]pyridazine (VI). 相似文献
100.