The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Two separate enzymatic assays were developed in order to test the selectivity of inhibitors in cholesterol biosynthesis. One assay detects inhibition of Δ 5,7 -sterol Δ 7 -reductase, the enzyme involved in the conversion of 7-dehydrocholesterol to cholesterol. Δ 5,7 -Sterol Δ 7 -reductase was inhibited by both RPR 101821, a protonated cyclohexylamine,...
YM 9429 (cis-1-[4-(p-menthan-8-yloxy)phenyl]piperidine) is a hypolipidemic agent with a potent and specific teratogenicity, inducing cleft palate and skeletal variations in rats. Since cleft palate is generally observed in the Smith-Lemli-Opitz syndrome, a common syndrome of multiple congenital anomalies caused by reduced activity of 7-dehydrocholesterol Δ 7 -reductase (3β-hydroxysteroid...
Cholesterol is oxidized by commercially available Pseudomonas fluorescens cholesterol oxidase to 6β-hydroperoxycholest-4-en-3-one as the initial product, with none of the expected product, cholest-4-en-3-one, formed. The transformation indicates that P. fluorescens cholesterol oxidase also acts as a flavoprotein dioxygenase.
We have used the expressio of the human estrogen receptor (hER) and two estrogen response elements linked to the lacZ gene in yeast (YES) to study the estrogenic and antiestrogenic activities of various phytochemicals. Coumestrol, α-zearalenol, or genistein could produce β-galactosidase activity comparable to estradiol, but these required concentrations 100 to 1000-fold greater than estradiol. These...
Oxidation of cholesterol (1a) or pregnenolone (1b) with pyridinium dichromate (PDC) in dimethylformamide (DMF) or in dichloromethane (DCM) and pyridinium chlorochromate (PCC) in DCM provided cholest-4-en-3,6-dione (2a) or pregn-4-en-3,6,20-trione (2b). TLC monitoration of the reactions implied that cholest-5-en-3-one (3a) or pregn-5-en-3,20-dione (3b) and cholest-4-en-3-one (4a) or pregn-4-en-3,20-dione...
Three new 9,11-secosterols, 3β,6α,11-trihydroxy-9,11-seco-5α-cholest-7-ene-9-one (1), 24S- (2a), and 24R-methyl-3β,6α,11-trihydroxy-9,11-seco-5α-cholest-7,22E-diene-9-one (2b), were isolated from the Indian Ocean gorgonia, Subergorgia suberosa. Their structures were established by spectroscopic data.
4α-(2-Propenyl)-5α-cholestan-3α-ol (LY295427) was previously identified from a Chinese hamster ovary (CHO) cell-based low density lipoprotein receptor/luciferase (LDLR/Luc) assay to be a potent transcriptional activator of the LDL receptor promoter in the presence of 25-hydroxycholesterol. To investigate the effect of the 24,25-unsaturation in the D-ring side chain (desmosterol D-ring side chain)...
Over the past 30 years, numerous studies in invertebrates and vertebrates have established a role of calcium in oocyte maturation as well as in the resumption and progression of follicular development. Polycystic ovarian syndrome (PCO) is characterized by hyperandrogenic chronic anovulation, theca cell hyperplasia, and arrested follicular development. The aim of this observational study was to determine...
4α-(2-Propenyl)-5α-cholest-24-en-3α-ol (3) was shown recently in a Chinese hamster ovary (CHO) cell-based low-density lipoprotein receptor/luciferase (LDLR/Luc) assay to be a potent transcriptional activator of the LDL receptor promoter in the presence of 25-hydroxycholesterol. Because of the involvement of 12α-hydroxylation in the metabolism of cholesterol, we are interested in investigating the...
24-Hydroxylated derivatives were synthesized in 24(R) and 24(S) forms by the convergent method as analogs related to 1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D 3 . In the convergent synthesis, the A-ring fragment, synthesized from diethyl D-tartarate, and the C/D-ring fragments in 24(R) and 24(S) forms (vitamin D numbering), obtained from vitamin D 2 via the Inhoffen-Lythgoe diol,...
The syntheses of the new 21,24-methano derivatives of 1α,25-dihydroxyvitamin D 3 [viz. 1(S),3(R)-dihydroxy-17(R)-(1',4'-cis-(4'-(1'-hydroxy-1'-methylethyl)-cyclo-h exyl))-9,10-seco-androsta-5(Z),7(E),10(19)-triene (MC 2108) and its (1',4'-trans)-isomer (MC 2110)] are described. The key step is the establishment, by Diels-Alder reaction on a CD-ring side chain diene intermediate prepared from...
From the fruiting bodies of Ascomycetes Tuber indicum, a new steroidal glucoside with polyhydroxy ergosterol nucleus, tuberoside (2), has been isolated along with additional four known ergosterol derivatives, (22E, 24R)-ergosta-7, 22-dien-3β, 5α, 6β-triol (1), 5α, 8α-epidioxy-(22E, 24R)-ergosta-6, 22-dien-3β-ol (3), (22E, 24R)-ergosta-5, 22-dien-3β-ol (4), and (22E, 24R)-ergosta-4, 6, 8(14), 22-tetraen-3-one...
Various methods of steroid analysis were assessed using radiolabeled steroids and thin layer chromatography. Three reversed phase chromatography systems were evaluated for separation and recovery of steroids extracted from blood, liver tissue and feces. The use of different numbers of Sep-Pak C 18 cartridges for the purification of steroid extracts was examined and steroid recoveries...
Aminosterols isolated from the dogfish shark Squalus acanthias are promising therapeutic agents in the treatment of infection and cancer. One of these, MSI-1436, has been shown to possess antimicrobial activity slightly better than squalamine. In this study, a series of analogs of MSI-1436 have been synthesized from stigmasterol. The 7α-hydroxy substituent of MSI-1436 was either omitted or the stereochemistry...
Phycomyces is a fungal producer of β-carotene and other beneficial metabolites. Several erg mutants of Phycomyces, originally selected to study the effects of membrane alteration on physiological responses, have now been used to gain information about sterol biosynthesis in filamentous fungi. One mutant, H23, and its progeny were found to be blocked at episterol C-5 dehydrogenase and did not produce...
This study reports the results of chemical and chromatographic studies which establish the presence of 3-keto allocholic acid (3kACA) in water extracts from spermiating male sea lamprey, Petromyzon marinus. This is the second compound to be isolated and identified from these extracts. The first was 3-keto petromyzonol sulfate (3kPZS), which was shown to act as strong pheromonal attractant for ovulated...
A technically simple route is described to individual epimers of side-chain derivatives of lanosterol (3β-hydroxy-5α-lanosta-8,24-diene). Epimerically pure 24,25-epoxy-, 24,25-dihydroxy- and 24-bromo-25-hydroxy-lanosterol have been prepared in good yield from commercial (50-60%) lanosterol. Hypophosphorous acid was used as a catalyst for the cohalogenation of the Δ 24(25 ...
This paper describes the efficient and stereospecific synthesis of cytotoxic dihydroxylated sterols, 24-methylene-cholest-5-ene-3β,7α-diol 1, and its C-7 epimer, 24-methylene-cholest-5-ene-3β,7β-diol 2. The crux of the synthesis is that the selective allylic oxidation of 24-methylene-cholesteryl acetate proceeds to 24-methylene-7-keto-cholesteryl acetate without extensive byproduct formation from...
Fluorescence techniques were used to study (1) the extent of insertion of the bioactive cyclic dipeptide cyclo(l-tyrosyl-l-prolyl), maculosin, in model systems of membranes of 1, 2-palmitoyl-sn-glycero-3-phosphatidyl choline (DPPC) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidyl choline (POPC), (2) its in-depth location in those lipidic membranes, and (3) the influence of cholesterol on the dipeptides's...
Penicisteroid C, a new polyoxygenated steroid was isolated from co-cultivation of Streptomyces piomogenus AS63D and Aspergillus niger using solid-state fermentation on rice medium. Additional diverse eleven known metabolites were identified: Fumigaclavine C, fumiquinazoline C, physcion, methylsulochrin, methyllinoleate, glycerol linoleate, cerebroside A, thymine, adenine, thymidine and adenosine....
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.