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101.
F. Coll A. Preiss M. Basterechea L. Kutschabsky D.L. Mola K. Schreiber G. Adam 《Phytochemistry》1984,23(4):883-885
A new solanocapsine-type alkaloid named aculeamine has been isolated from roots of Solanum aculeatum and its structure elucidated by physical methods including X-ray analysis as 22,26-epimino-22β-methoxy- 16α,23-epoxy-5α,22αH,25βH-cholestane-3β-ol. The corresponding 23β-ethoxy compound was also isolated as an artefact. 相似文献
102.
From the aerial parts of Bauhinia candicans a novel steroidal glycoside was isolated and identified as sitosterol 3-O-α-D-riburonofuranoside. 相似文献
103.
Jinrun Dong Xingrong Peng Lei Li Shuangyang Lu Lin Zhou Minghua Qiu 《Bioorganic & medicinal chemistry letters》2018,28(9):1520-1524
Eight new C21 steroidal glycosides, namely cynanotins A–H (1–8), together with fifteen known analogues, were isolated from the roots of Cynanchum otophyllum. Their structures were elucidated by spectroscopic analysis and chemical methods. In this study, all of isolates were tested for their vitro inhibitory activities against five human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480). Compounds 3–15 showed moderate cytotoxic activities against HL-60 cell lines with IC50 values ranging from 11.4 to 37.9?µM. Compounds 5, 9, and 10 showed marked or moderate cytotoxic activities against five human tumor cell lines with IC50 values ranging from 11.4 to 36.7?µM. Compound 11 displayed moderate cytotoxic activities against HL-60, SMMC-7721, MCF-7 and SW480 cell lines with IC50 values of 12.2–30.8?µM. Compared to the positive control (IC50: 35.0?µM), compounds 5, 9–11 exhibited more potential inhibitory activity against MCF-7 cells (IC50: 16.1–25.6?µM). 相似文献
104.
Rita Skoda-F ldes Zita Cs kai L szl Koll r G bor Szalontai Judit Horv th Zolt n Tuba 《Steroids》1995,60(12):786-790
17-Iodo-Δ16 steroids undergo selective dimerization and carbonylative dimerization in the presence of palladium catalysts in dimethylformamide which result in 16–17′-coupled dienes and 17-carboxylic anhydrides, respectively. Moderate to good yields have been obtained for both types of dimers. 相似文献
105.
We have examined the incorporation and metabolism of [14C] stearic acid within the total lipids of HTC rat-hepatoma cells in suspension culture in presence and in absence of steroidal hormone stimulation. Both, glucocorticoids (dexamethasone, cortisol and corticosterone) and mineralocorticoids (deoxycorticosterone and aldosterone) as well as the estrogen -estradiol and the androgen testosterone enhanced the extent of 9 desaturation to oleic acid of the saturated precursors, whereas only the two mineralocorticoids affected the incorporation rate of the exogenous acid into total cellular lipids, thus promoting a little stimulation. Furthermore, all the hormones tested increased the radiolabelling of the total cellular phospholipids except deoxycorticosterone and testosterone, the former having no effect and the latter exerting a moderate inhibition. On the other hand, the incorporation of14C into neutral lipids was stimulated by testosterone, in contrast to the inhibition of this parameter observed exclusively with either the mineralocorticoids or the estrogen. Within the phospholipid subclasses, the radiolabelling of phosphatidylcholine was augmented by means of all the steroids tested save deoxycorticosterone and testosterone, whereas phosphatidylethanolamine exhibited a decrease only in the presence of testosterone. In a similar fashion, within the neutral lipids, the predominating triglyceride fraction was preferentially labelled—at the expense of other subclasses of lesser abundance—upon treatment with the steroids except aldosterone, which exerted no effect. The results obtained were correlated with those changes observed in the mass distribution of the different lipid subclasses either with or without prior hormonal stimulation.Abbreviations ALD
aldosterone
- ANOVAR
analyses of variance
- CE
cholesterol esters
- Cl
cortisol
- CLN
cardiolipin
- Cst
corticosterone
- CH
cholesterol
- DG
diacylglycerides
- DOC
11-deoxycorticosterone
- Dx
dexamethasone phosphate salt
- ßE
17--estradiol
- FAME
fatty acid methyl esters
- GLC
gas-lipid chromatography
- HEPES
N-2-hydroxyethyl-piperazine-N-2-ethanosulfonic acid
- HTC
hepatoma tissue culture
- IMEM-Zo
improved minimal essential medium-Zinc option
- LPC
lysophosphatidyl-choline
- LPL
lysophospholipids
- MG
monoacylglycerides
- NEFA
free fatty acids
- PC
phosphatidyl-choline
- PE
phosphatidyl-ethanolamine
- PG
phosphatidyl-glycerol
- PI
phosphadyl-inositol
- PS
phosphadidyl-serine
- SM
sphingomyelin
- TG
triacylglycerides
- TLC
thin-layer chromatography
- Tst
testosterone
Members of the Carrera del Investigador Cientifico, CONICET, Argentina. 相似文献
106.
107.
The 13C NMR chemical shifts of 130 naturally occurring steroidal sapogenins and saponin derivatives published up to 1983 are listed and a number of methods for signal assignment are explained. The utility of 13C NMR spectral analysis for the structure elucidation of these compounds is discussed. 相似文献
108.
Ryan J. Bixenmann Phyllis D. Coley Alexander Weinhold Thomas A. Kursar 《Ecology and evolution》2016,6(17):6037-6049
Theoretical and empirical studies show that, when past or current herbivory is a reliable cue of future attack and defenses are costly, defenses can be induced only when needed and thereby permit investment in other functions such as growth or reproduction. Theory also states that, in environments where herbivory is constantly high, constitutive defenses should be favored. Here, we present data to support the second aspect of the induced resistance hypothesis. We examined herbivore‐induced responses for four species of Inga (Fabaceae), a common canopy tree in Neotropical forests. We quantified chemical defenses of expanding leaves, including phenolic, saponin and toxic amino acids, in experimental field treatments with and without caterpillars. Because young leaves lack fiber and are higher in protein than mature leaves, they typically lose >25% of their leaf area during the few weeks of expansion. We predicted that the high rates of attack would select for investment in constitutive defenses over induction. Our data show that chemical defenses were quite unresponsive to herbivory. We demonstrated that expanding leaves showed no or only small increases in investment in secondary metabolites, and no qualitative changes in the phenolic compound profile in response to herbivory. The proteinogenic amino acid tyrosine, which can be toxic at high concentrations, showed the greatest levels of induction. Synthesis: These results provide some of the first support for theoretical predictions that the evolution of induced vs. constitutive defenses depends on the risk of herbivory. In habitats with constant and high potential losses to herbivores, such as tropical rainforests, high investments in constitutive defenses are favored over induction. 相似文献
109.
The steroidal sapogenins yielded by the leaves of Agave aurea, A. avellanidens, A. cerulata, A. cerulata ssp. subcerulata, A. cocui, A. goldmaniana, A. shawii and Furcraeamacrophylla are recorded. In all these species, hecogenin and tigogenin were the major sapogenins isolated. Gitogenin was found in the extracts of all the leaf samples, except that of A. shawii, and manogenin and 9-dehydromanogenin in all but that of A. cocui. Chlorogenin was isolated from A. cocui, but was not detected in any of the other species examined. Qualitative and quantitative variations were found in the sapogenin contents of extracts of different regions of the same leaves of A. cocui and F. macrophylla. In particular, hecogenin predominated in the basal regions and tigogenin in the apical. 相似文献
110.
J. Kesselmeier 《Protoplasma》1980,104(3-4):295-306
Summary Chloroplasts of mixotrophically grown suspension cultures ofNicotiana tabacum possess the capability to build up para-crystalline prolamellar bodies (PLBs), resembling those ofAvena etioplasts. After dark incubation of light-grown tissue the plastids show PLBs, whose crystalline character depends on the duration of the dark incubation and the moment of the growth cycle, the chloroplasts are induced to build up PLBs. These chloro-etioplasts contain steroidal saponins closely related to the PLB-appearance. The relations between the PLB- and saponin occurrence, reported here and in previous papers, lead to the conclusion, that steroidal saponins are the building units of PLBs in many different plant species. A model for saponin synthesis and degradation, depending on dark- or light-incubation is discussed. 相似文献