排序方式: 共有39条查询结果,搜索用时 15 毫秒
1.
Sanjib Das Robindra N. Baruah Ram P. Sharma Jogendra N. Baruah Palaniappan Kulanthaivel Werner Herz 《Phytochemistry》1983,22(9):1989-1991
Cynaropicrin, 11βH-11,13-dihydrodesacylcynaropicrin, aguerins A and B, isoamberboin and the new guaianolides saussureolide and 11βH-11,13-dihydrodesacylcynaropicrin 8-β-d-glucoside were isolated from Saussurea affinis. 相似文献
2.
P Kulanthaivel B J Simon F H Leibach V B Mahesh V Ganapathy 《Biochimica et biophysica acta》1990,1024(2):385-389
We examined the effects of phenylarsine oxide, a reagent specific for vicinal dithiol groups, on the catalytic activities, Na+ influx and H+ efflux, of the human placental Na(+)-H+ exchanger. Treatment of the placental brush-border membrane vesicles with the reagent markedly inhibited both the activities. The inhibition was partially reversible by dithiols. The effect of phenylarsine oxide was to reduce the maximal velocity of the exchanger without influencing its affinity for Na+. The exchanger was partially protected from this inhibition by amiloride but not by cimetidine even though both these compounds interacted with the Na(+)-binding site. The data demonstrate that vicinal dithiol groups are essential for the catalytic function of the placental Na(+)-H+ exchanger and that the critical dithiol groups are located at a site distinct from the Na(+)-binding site. 相似文献
3.
Kuo F Gillespie TA Kulanthaivel P Lantz RJ Ma TW Nelson DL Threlkeld PG Wheeler WJ Yi P Zmijewski M 《Bioorganic & medicinal chemistry letters》2004,14(13):3481-3486
Several putative phase I duloxetine metabolites, 4-hydroxy-, 5-hydroxy-, 6-hydroxy-, 5-hydroxy-6-methoxy-, 6-hydroxy-5-methoxy-, 5,6-dihydroxy-, and 4,6-dihydroxyduloxetine were synthesized, and their phase II metabolite as glucuronide or sulfate conjugates were also synthesized. Their in vitro binding activities were compared to that of parent compound duloxetine. 相似文献
4.
Investigation of Helianthella quinquenervis afforded, in addition to several known 6-acetylchromenes, 3-prenyl-4-hydroxyphenone and the benzofuran encecalin, cis- and trans-2,2-dimethyl-3,4,7-trihydroxy-6- acetylchroman. 相似文献
5.
Costunolide and the isobutylamides of 2E,4E,8Z,10Z- and 2E,4E,8Z,10E-dodeca-2,4,8,10-tetraenoic acid were isolated from the roots of Salmea scandens. 相似文献
6.
P Kulanthaivel B J Simon G Burckhardt V B Mahesh F H Leibach V Ganapathy 《Biochemistry》1990,29(48):10807-10813
Transient exposure of human placental brush-border membrane vesicles to cholate reorients the ATP-driven H+ pump, enabling the pump to transport H+ into the vesicles upon addition of ATP to the external medium. H+ uptake can be measured in these vesicles by following the decrease in the absorbance of acridine orange, a delta pH indicator. We investigated the role of tyrosyl residues in the catalytic function of the H+ pump by studying the effects of tyrosyl group specific reagents on ATP-driven H+ uptake in cholate-pretreated membrane vesicles. The reagents tested were 7-chloro-4-nitro-2,1,3-benzoxadiazole (NBD-Cl), N-acetylimidazole, tetranitromethane, and p-nitrobenzenesulfonyl fluoride. Treatment of the membrane vesicles with these reagents resulted in the inhibition of the ATP-driven H+ uptake, and the inhibitory potency was in the following order: NBD-Cl greater than tetranitromethane greater than p-nitrobenzenesulfonyl fluoride greater than N-acetylimidazole. The inhibition of the H+ pump by NBD-Cl was reversible by 2-mercaptoethanol, and the inhibition by N-acetylimidazole was reversible by hydroxylamine. Since these reagents are not absolutely specific for tyrosyl groups and can also react with thiol groups, we studied the interaction of N-acetylimidazole with the H+ pump whose triol groups were masked by reaction with p-(chloromercuri)benzenesulfonate. The SH-masked pump was totally inactive, but the activity could be restored by dithiothreitol. On the contrary, the activity of the SH-masked H+ pump which was subsequently treated with N-acetylimidazole could not be restored by dithiothreitol, suggesting that thiol groups were not involved in the inhibition of the H+ pump by N-acetylimidazole.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
Umesh C. Pandey Ashok K. Singhal Nabin C. Barua R.P. Sharma Jogendra N. Baruah Kinzo Watanabe Palaniappan Kulanthaivel Werner Herz 《Phytochemistry》1984,23(2):391-397
Extraction of Conyza japonica gave strictic acid, ent-2β-hydroxy-15,16-epoxy-3,13(16),14-clerodatrien-18-oic acid and 5,7-dihydroxy-3,8,4′-trimethoxyflavone. Extraction of Grangea maderaspatana gave (-)-hardwickiic acid, ent-15,16-epoxy-1,3,13(16),14-clerodatetraen-18-oic acid and 3-hydroxy-8-acetoxypentadeca-1,9,14-trien-4,6-diyne. The structure of ent-2β-hydroxy-15,16-epoxy-3,13(16),14-cleroclatrien-18-oic acid was deduced by spectroscopic methods and by partial synthesis from (-)-hardwickiic acid and the stereochemistries of strictic acid and (ent-15,16-epoxy-1,3,13(16),14-clerodatraen-18-oic acid were established by correlation with ent-2β-hydroxy-15,16-epoxy-3,13(16),14-clerodatrien-18-oic acid. 相似文献
8.
Juan C. Oberti Virginia E. Sosa Palaniappan Kulanthaivel Werner Herz 《Phytochemistry》1984,23(9):2003-2006
Two new ent-norlabdane triols were isolated from the above-ground parts of Austroeupatorium inulaefolium. 相似文献
9.
Wheeler WJ Clodfelter DK Collado I Kulanthaivel P Pedregal C Stoddard EA Wright RA Schoepp DD 《Bioorganic & medicinal chemistry letters》2005,15(2):349-351
We report herein the synthesis of the tritium labeled isotopomer of 1 and its use as a radioligand to label mGlu8 receptors in rat forebrain membranes as well as cloned human recombinant mGlu receptors. [(3)H]-1 was synthesized by the NaBT(4) reduction of an activated analog of 5. [(3)H]-1 bound appreciably to recombinant human mGlu2, mGlu3 and mGlu8 receptors and to rat forebrain membranes and was displaced by L-glutamate and L-(+)-2 amino-4-phosphonobutyric acid. The results indicate that [(3)H]-1 should be a useful ligand for the study of mGluR2, 3, and 8 receptors in cloned cell lines and possibly brain tissue. 相似文献