首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
A new lupane derivative isolated from Euonymus revolutus (Celastraceae) has been established to be 2α,3α-dihydroxy-lup-20(29)-en-28-oic acid on the basis of chemical interconversions and spectroscopic data.  相似文献   

3.
The assignment of the lup-20(29)en-28-ol structure for jasminol, and subsequent synthetic proof, are shown to be insecure.  相似文献   

4.
A new natural triterpenoid, characterized as 3β-hydroxylup-20(29)-en-27-oic acid, has been isolated from the roots of Hyptis suaveolens in additi  相似文献   

5.
The investigation of stems and leaves of Catha cassinoides afforded, in addition to sitosterol, β-amyrin, ursolic acid, lup-20(29)-en-3β,30-diol and friedelin, three new pentacyclic triterpenes: 30-hydroxyfriedelan-3-one, 29-hydroxyfriedelan-3-one and 3-oxo-friedelan-29-oic acid. The structures ofthese were determined by spectral studies and correlations, and were confirmed by X-ray analysis of 29-hydroxyfriedelan-3-one acetate.  相似文献   

6.
Two new triterpenoid carboxylic acids have been isolated from leaves of Acanthopanax trifoliatus and their structures elucidated as 3α, 11α-dihydroxylup-20(29)-en-28-oic acid and 30α, 11α,23-trihydroxylup-20(29)-en-28-oic acid by physical data and chemical transformations.  相似文献   

7.
The new triterpene 3α,11α-dihydroxy-23-oxo-lup-20(29)-en-28-oic acid was isolated from Acanthopanax trifoliatus. Its structure has been determined on the basis of spectroscopic data and chemical transformations.  相似文献   

8.
Two new triterpene ketols were isolated from the whole herb of Euphorbia supina; one of these compounds, named supinenolone E, was confirmed to be 3β-hydroxy-D:C-friedo-B′: A′-neogammacer-8-en-7-one(3β-hydroxyfern-8-en-7-one) and the another to be 3β-hydroxy-D:C-friedo-olean-8-en-7-one (3β-hydroxymultuiflor-8-en-7-one) on the basis of chemical and spectral evidence.  相似文献   

9.
From Acanthopanax trifoliatus the new nor-triterpenes 24-nor-3α, 11α-dihydroxy-lup-20(29)-en-28-oic acid and 24-nor-11α-hydroxy-3-oxo-lup-20(29)-en-28-oic acid were isolated. Their structures were determined on the basis of spectroscopic data, X-ray analysis and chemical transformations.  相似文献   

10.
A lupane triterpene from frankincense (Boswellia sp., Burseraceae)   总被引:2,自引:0,他引:2  
A new lupane-type triterpene, 3alpha-hydroxy-lup-20(29)-en-24-oic acid, was isolated from the methanolic extract of "Erytrean-type" resin of commercial frankincense together with the known 3alpha-hydroxy-olean-12-en-24-oic acid (alpha-boswellic acid) and 3alpha-hydroxy-urs-12-en-24-oic acid (beta-boswellic acid). Their structures were characterized on the basis of chemical and spectral evidence including two dimensional NMR experiments and mass spectrometric techniques.  相似文献   

11.
Transformation of a steroidogenic mouse adrenal cell line (Y-1) by simian adenovirus SA7 produced a cell line with low apparent steroidogenic activity. The effect of ACTH and cholera toxin on cyclic AMP production was similar in both not transformed and virus-transformed cells and activity of cyclic AMP-dependent protein kinase was also similar in both cells. In transformed cells, cholesterol was metabolized to delta 5-3 beta-hydroxysteroids, mainly 20 alpha-dihydropregnenolone while in not transformed cells, the major metabolites were delta 4-3 ketosteroids (20 alpha-dihydro- and 11 beta-hydroxy-20 alpha-dihydroprogesterone). In both cell lines ACTH increased the metabolism of cholesterol. Further studies with labelled pregnenolone and progesterone revealed a loss of delta 5-3 beta-hydroxysteroid dehydrogenase/isomerase and 11 beta-hydroxylase activity in the transformed cells.  相似文献   

12.
Two new triterpenes from the root of Periandra dulcis were found to be 3,25-dioxoolean-12(13)-en-30-oic acid and 3,25-dioxoolean-18(19)-en-30-oic acid.  相似文献   

13.
Fourteen pentacyclic triterpenes, which included ten D:A-friedooleananes, three lup-20(29)-enes and 2α,3α-dihydroxy-olean-12-en-28-oic acid, were isolated from the stem bark extract of Euonymus revolutus.  相似文献   

14.
The effect of different doses of estradiol-17β (E2) on the netabolic pregnenolone to progesterone pathway in fragments of human term placenta incubated in vitro was studied. Doses considered as being physiological of 0.09 and 0.9 μM had a stimulatory effect on the conversion (p < 0.008 to 0.0l6). However, a supraphysiological dose of 45 μM showed an inhibitory activity related to the maximal stimulation (p < 0.03). A dose of 0.9 μM E2 favoured the accumulation of (3H)-progesterone in the tissue (p < 0.05). These results suggest that E2 may regulate the synthesis of progesterone in human term placenta.  相似文献   

15.
The hexane extract of Wyethia mollis contains the n-alkanes C15-C18, C20-C25, C27 and C29. Linoleic acid was the only detectable acidic component. A mass spectral analysis of the wax ester fraction indicated that it was a mixture of homologues, the saturated even-carbon acids n-C16-C30 esterfield with the saturated even-carbon alcohols n-C18-C26. The chloroform extract yielded the known isoflavones santal and 3′-O-methylorobol along with a new lanostane-type triterpene, 22,25-epoxy-lanosta-7:9(11)-dien-3-one. The wide distribution of n-alkanes and the decreased odd-even carbon ratio are consistent with the proposed primitive nature of this plant.  相似文献   

16.
Methods für the determination of urinary free corticosterone, free aldosterone and free 11-deoxycorticosterone (DOC) in rats are described. The free corticosteroids were measured in urine samples of 0.1–0.5 (2.0) ml by radioimmunoassay after purification by column chromatography. The validity of the methods is demonstrated by the data of the free urinary corticoids under basal conditions and after adrenal suppression and various forms of adrenal stimulation. The basal excretion of free corticosterone, free aldosterone and free DOC was 123.71 ± 15.31 (x? ± SD), 3.87 ± 1.29 and 10.61 ± 2.24 ng/day, respectively, exhibiting a decrease to 26.20 ± 5.21, 1.05 ± 0.47 and 1.35 ± 1.20 ng/day after adrenal suppression by dexamethasone. Irrespective of the mode of adrenal stimulation i.e., synthetic ACTH and systemic (cold, hunger) or neurotrophic (ether, reserpine) stress stimuli free corticosterone increased to about 450 ng/day, while free aldosterone excretion decreased during hunger and cold and was strongly enhanced after the application of reserpine. Furthermore, determination of urinary free DOC, which increased by a factor of 4, may be applied in the metyrapone test. There was a good correlation between the excretion of free corticosterone and that of free aldosterone and free DOC under basal conditions and after ACTH application, demonstrating that ACTH is responsible for the secretion of all the 3 corticoids measured. It is concluded, that the measurement of the urinary excretion of corticosterone, aldosterone and DOC is a valuable parameter of adrenal function in rats. Furthermore, in small laboratory animals like rats steroid measurements in urine are often more advantageous than Measurements in plasma.  相似文献   

17.
18.
R J Etches 《Steroids》1976,28(6):763-773
A radioimmunoassay for corticosterone was developed using an antibody to corticosterone-21-hemisuccinate:bovine serum albumin. The assay possessed good specificity, sensitivity and reproducibility and required minimal sample preparation. Tests of adrenal function showed that stimulation of the adrenal with exogenous ACTH and with dexamethasone caused an increase and decrease, respectively, in plasma concentrations of corticosterone. Exposure to cold environmental temperatures caused an increase in plasma corticosterone. Handling and the removal of blood samples by venepuncture had no effect upon the concentration of corticosterone. It was concluded that this assay would accurately measure the response to stresses which affect the pituitary-adrenal axis.  相似文献   

19.
Two new epimeric triterpenoid acids, gymnosporic acid, 3β-hydroxy-(20R)-lupan-29-oic acid, wallichianic acid, 3β-hydroxy-(20S)-lupan-29-oic acid and a new diol wallichianol, (20S)-lupane-3β,29-diol have been isolated from Gymnosporia wallichiana, in addition to β-amyrin, friedelin, 3β-hydroxy-29-norlupan-20-one and dulcitol.  相似文献   

20.
Pseudobrickellia brasiliensis afforded, in addition to known compounds, a new germacradiene derivative and a hydroxy-α-amyrin.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号