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PubMed1988

Steinernema feltiae (= Neoaplectana carpocapsae): effect of sterols and hypolipidemic agents on development.

The structure and concentration of sterol in a lipid-defined artificial medium affected the development of the entomogenous nematode, Steinernema feltiae (= Neoaplectana carpocapsae). The nematode grew normally in vitro when the medium was supplemented with delta 5-desalkylsterol (cholesterol) or delta 5-desalkylsteryl ester (cholesterol oleate). The minimum amount of cholesterol in the medium that was necessary to support the development of S. feltiae to the climax population (i.e., dauer stage) was 0.0025%. The nematode also completed its life cycle normally when delta 0- or delta 7-desalkylsterols (cholestanol and lathosterol) were substituted for cholesterol. In contrast, development was inhibited when the medium contained delta 5,7-desalkylsterol (7-dehydrocholesterol); however, the nematode population reached the climax stage, in medium containing this sterol, when cholesterol was also present. S. feltiae was able to utilize delta 5- and delta 0-24 alpha-ethylsterols (sitosterol and sitostanol) as dietary sterols; however, when a delta 22-bond was introduced into the side chain (stigmasterol) the rate of development of the nematode slowed significantly. The growth of the nematode was also retarded when the medium contained delta 5,7,22-24 beta-methylsterol (ergosterol). The nematode population reached the climax stage in medium containing delta 8,24-4,14 alpha-trimethylsterol (lanosterol) only when cholesterol was also present. When S. feltiae was exposed to certain hypolipidemic agents, which are known to lower the level of lipids in human plasma (clofibrate, cholestyramine resin, niacin, and D-thyroxine), all but D-thyroxine affected the growth and development of the nematode in vivo (in Heliothis zea) and/or in vitro. Therefore further studies are warranted to determine how these drugs affect the lipid biochemistry of this nematode.

Animals↗
PubMed1995

Effect of 6-ketocholestanol on FCCP- and DNP-induced uncoupling in plant mitochondria.

Effect of 6-ketocholestanol on FCCP-induced and DNP-induced uncoupling in beef liver and pea stem mitochondria was studied, under experimental conditions at which this steroid abolished the effect of low concentrations of FCCP and other most potent uncouplers in rat mitochondria [Starkov et al. (1994) FEBS Lett., 355, 305-308]. It is shown that, in both types of mitochondria, 6-ketocholestanol prevents or reverses the uncoupling induced by low concentrations of FCCP, but not that caused by high concentrations of FCCP or by any concentration of DNP. Progesterone and male sex hormones, showing recoupling capability in animal mitochondria, appear to be ineffective in the plant system. Cholesterol does not recouple in both animal and plant mitochondria. Plant steroids, such as beta-sitosterol and stigmasterol, are also without effect.

2,4-Dinitrophenol↗
PubMed1984

Effects of feeding cholesterol and mixed plant sterols on the fecal excretion of acidic steroids in rhesus monkeys.

The effects of feeding diets with high or low amounts of cholesterol and with low or high levels of mixed plant sterols (sitosterol: campesterol: stigmasterol, 60:35:5) on the daily fecal excretion of acidic steroids were studied in rhesus monkeys. During periods of low dietary plant sterol, total fecal acidic steroid excretion was 43% lower (P less than 0.01) during low dietary cholesterol than during high dietary cholesterol. During periods of high dietary plant sterols the fecal acidic steroid excretion was 113% higher (P less than 0.01) with low dietary cholesterol than with high dietary cholesterol. Addition of mixed plant sterols to the low-cholesterol diet produced nearly a 2-fold increase (P less than 0.005) whereas, such an addition to the high cholesterol diet produced a significant decrease by about 53% (P less than 0.025) in the total fecal acidic steroid excretion. The results suggest that the effect of cholesterol feeding on fecal acidic steroid excretion depends on the level of plant sterols in the diet. This interaction of the effects of cholesterol and plant sterols on the fecal acidic steroid excretion is probably related to the inhibitory effect of plant sterols on cholesterol absorption.

Animals↗
PubMed1986

Absorption of cholesterol and beta-sitosterol from cigarette smoke in Macaca mulatta.

When smoke from single cigarettes containing [4-14C]cholesterol or beta-[4-14C]sitosterol was delivered to the lungs of Rhesus macaques, plasma contained radiolabeled sterols up to 50 days later. Since cholesterol, as well as plant sterols (campesterol, stigmasterol and beta-sitosterol), are normally present in cigarette smoke, our observations suggest that protracted absorption of sterols occurs after cigarette smoking.

Animals↗
PubMed1991

Relationships of serum plant sterols (phytosterols) and cholesterol in 595 hypercholesterolemic subjects, and familial aggregation of phytosterols, cholesterol, and premature coronary heart disease in hyperphytosterolemic probands and their first-degree relatives.

To assess relationships of serum phytosterols (plant sterols [P]) to serum cholesterol (C), P were measured by gas-liquid chromatography (GLC) in 595 hypercholesterolemics (top C quintile in screening of 3,472 self-referred subjects). A second specific aim was to determine whether high serum P would track over time and whether they would predict familial aggregation of high C, high low-density lipoprotein cholesterol (LDLC), high apolipoprotein (apo) B, and increased premature coronary heart disease (CHD) in hyperphytosterolemic probands and their first-degree relatives. Mean +/- (SD) C was 260 +/- 56 mg/dL, campesterol (CAMP) was 2.10 +/- 1.6 micrograms/mL, stigmasterol (STIG) 1.71 +/- 1.67, sitosterol (SIT) 2.98 +/- 1.61, and total P 6.79 +/- 3.66 micrograms/mL. Serum C correlated with CAMP (r = .15, P less than or equal to .001), STIG (r = .10, P less than or equal to .02), SIT (r = .34, P less than or equal to .0001), and total P (r = .29, P less than or equal to .0001). High serum CAMP and STIG were associated with a personal or family history of CHD in subjects less than or equal to age 55 years (premature CHD). In 21 hyperphytosterolemic probands who initially had at least one P at or above the 95th percentile and a second P at or above the 75th percentile, P were remeasured 2 years later. Initial and 2-year follow-up CAMP, STIG, and SIT did not differ (P greater than .7). Initial and follow-up CAMP were correlated (r = .47, P = .03).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1991

Leucasin, a triterpene saponin from Leucas nutans.

A new saponin, leucasin, has been isolated from Leucas nutans and characterized on the basis of chemical investigation and spectroscopic studies as 3-O-[beta-D-glucopyranosyl(1----2)beta-D-glucopyranosyl]2 alpha, 3 beta-dihydroxylup-20(29)-ene. Lupeol palmitate, sitosterol and stigmasterol were also isolated.

Carbohydrate Sequence↗
PubMed1996

Secoiridoids and antifungal aromatic acids from Gentiana algida.

Fractionation of an aqueous acetone extract of the whole herb of Gentiana algida gave one new [2'-(o,m-dihydroxybenzyl)sweroside] and five known secoiridoids, together with anofinic acid, fomannoxin acid, sitosterol, daucosterol, stigmasterol, oleanolic acid, orientin and gentianose. The structures were determined by spectral methods and a few chemical transformations. Anofinic acid and fomannoxin acid were found to be active against Cladosporium cucumerinum, a plant pathogenic fungus. Preliminary structure-activity studies indicated that the presence of carboxylic moieties in these acids was presumably a precondition for activity, whereas their methyl esters, inactive to the fungus, were active against the human pathogenic yeast Candida albicans. The chemotaxonomic significance of the isolates is discussed briefly.

Acetone↗
PubMed1996

Acyl secoiridoids and antifungal constituents from Gentiana macrophylla.

LC-UV-mass spectrometry and bioassay co-directed fractionation of an aqueous acetone extract of the roots of Gentiana macrophylla gave three new chromene derivatives and two novel and six known secoiridoids, along with kurarinone, kushenol I, beta-sitosterol, stigmasterol, daucosterol, beta-sitosterol-3-O-gentiobioside, alpha-amyrin, oleanolic acid, isovitexin, gentiobiose and methyl 2-hydroxy-3-(1-beta-D-glucopyranosyl)oxybenzoate. The structures of the new products were established from spectral and chemical evidence as 2-methoxyanofinic acid and macrophyllosides A-D. The six known secoiridoids were gentiopicroside, sweroside, 6'-O-beta-D-glucosylgentiopicroside, 6'-O-beta-D-glucosylsweroside, trifloroside and rindoside. The new acid (2-methoxyanofinic acid), its methyl ester, kurarinone and kushenol I were shown to be active against the plant pathogenic fungus Cladosporium cucumerinum. The methyl ester and kurarinone inhibited also the growth of the human pathogenic yeast Candida albicans. Structure-activity relationships were studied. Thus, addition of a methoxyl group to the benzene nucleus of anofinic acid (2,2-dimethyl-2H-1-benzopyran-6-carboxylic acid) increased the antifungal activity remarkably whereas glycosylation at the carboxylic moiety was found to remove the activity. Esterification of the new acid induced its activity against C. albicans, but decreased its growth inhibition properties against C. cucumerinum. Hydroxylation of kurarinone at the 3 beta-position removed its activity against C. albicans and decreased the inhibition of C. cucumerinum. In addition, the chemotaxonomic significance of the identified constituents is discussed.

Antifungal Agents↗
PubMed1977

4-Desmethylsgerols in the seeds of Solanaceae.

Thirteen 4-desmethylsterols: cholesterol, 24-methylcholesterol, 24-ethylcholesterol, stigmasterol, 24-methylcholesta-5,24-dienol, 24-ethylcholesta-5,24-dienol, 28-isofucosterol, 24-methylenecholesterol, cholestanol, 24-methylcholestanol, 24-ethylcholestanol, cholest-7-enol and 24-ethylcholest-22-enol, were identified in the seeds of solanaceous plants. The distribution of these 4-demethylsterols in the seeds of eleven plants among seven genera of the Solanaceae family was determined.

Magnetic Resonance Spectroscopy↗
PubMed1992

Steroids, the steroid community, and Upjohn in perspective: a profile of innovation.

The announcement in 1949 at the Mayo Clinic of the dramatic effect of cortisone in alleviating the symptoms of rheumatoid arthritis triggered a competitive worldwide research and development effort directed toward a single goal, the practical synthesis of the rare corticosteroids. The confluence of an extraordinary coalescence of multiple events and circumstances in the growth of the Upjohn Company with the Mayo discovery, inclusive of a pioneering role in the steroid field, conspired to create an environment ripe for innovation. The breakthrough, which gave Upjohn an early competitive edge, followed with startling swiftness. A common mold of the genus Rhizopus was found to introduce enzymatically an 11 alpha-hydroxyl group directly into the female hormone progesterone, which had just been synthesized from the soybean sterol stigmasterol--a one-step solution to the known multistep alternatives for 11-oxygenation. Retrospective analysis of this event in perspective with other key developments before and after at Upjohn and in the steroid community reveals a striking profile of ongoing innovation. A parallel scenario in kind was repeated at Upjohn a quarter century later. The sister soybean sterol sitosterol was radically degraded microbiologically and concurrently oxygenated in ring C to produce 9 alpha-hydroxyandrostenedione, an alternative key intermediate for corticoid synthesis. New chemical processes, highly integrated with existing processes, assured the continuation of Upjohn's leading role in steroid hormone production.

Cortisone↗
PubMed1989

Neutralization of lethal and myotoxic activities of South American rattlesnake venom by extracts and constituents of the plant Eclipta prostrata (Asteraceae).

Ethanolic extracts of the aerial parts of Eclipta prostrata L. (Asteraceae) neutralized the lethal activity of the venom of South American rattlesnake (Crotalus durissus terrificus) when mixed in vitro before i.p. injection into adult Swiss mice. Samples of ethanolic extract corresponding to 1.8 mg of dry extract per animal neutralized up to four lethal doses of the venom (LD50 = 0.08 micrograms venom/g animal). Three substances isolated from the plant--wedelolactone (0.54 mg/animal), sitosterol (2.3 mg/animal) and stigmasterol (2.3 mg/animal)--were able to neutralize three lethal doses of the venom. Aqueous extracts of the plant inhibited the release of creatine kinase from isolated rat muscle exposed to the crude venom. The protection conferred against the myotoxic effects of the venom could be demonstrated also in vivo, when the venom was preincubated with the extract prior to injection into mice.

Animals↗
PubMed1991

Identification of soybean dust as an epidemic asthma agent in urban areas by molecular marker and RAST analysis of aerosols.

From 1981 to 1987, 26 outbreaks of asthma have occurred in the city of Barcelona, Spain, affecting a total of 687 subjects and causing 1155 emergency room admissions. Assays of urban aerosols collected with high-volume samplers between October 1986 and May 1989 have indicated that soybean dust originating from harbor activities (and not traffic or industrial pollution) is the causal agent for these epidemics. Soybean particulates in the filters have been characterized from the composition of the alcohol fraction, namely, campesterol, stigmasterol, beta-sitosterol, n-triacontan-1-ol, and n-dotriacontan-1-ol, constituting a series of aerosol components correlated with the epidemiologic data. This result has also been confirmed by immunochemical assay of specific soybean allergens. The concentration of these sterols in the air corresponds to a 24-hour average level of soybean dust in the order of 25 micrograms/m3 on epidemic days. These results suggest the advisability of monitoring soybean dust in air particulates of populated areas surrounding soybean storage or processing plants. The techniques presented here afford a simple way for the recognition of soybean dust in aerosols containing high concentrations of organic pollutants of traffic or industrial origin.

Aerosols↗
PubMed1994

The magical and medicinal usage of Stangeria eriopus in South Africa.

The underground caudex of the cycad Stangeria eriopus is used extensively by several ethnic groups in South Africa, mainly as an ingredient in magical potions but also as an emetic. An assessment of two main outlets showed that 3410 plants were sold in the month of July 1992; continued usage of this material now threatens the remaining plant populations. A proximate analysis of the caudex material gives high carbohydrate content with only small percentages of fat, protein, fibre and ash. An unusually high content of sodium sulphate may explain the efficacy of Stangeria-containing preparations as an emetic. The phytosterols sitosterol and stigmasterol are present in a 4:1 ratio while the fatty acid component comprises palmitic, oleic, stearic and arachidic acids. Twelve amino acids were identified in the material, including the non-protein amino acids beta-alanine, gamma-aminobutyric acid and pyroglutamic acid. The candidate neurotoxin beta-N-methylamino-L-alanine could not be detected but cycasin is present at the levels of 0.17% and 0.21% in fresh and dry caudex material, respectively and appears to be accompanied by the related toxin, macrozamin.

Attitude to Health↗
PubMed2006

Moderately elevated plant sterol levels are associated with reduced cardiovascular risk--the LASA study.

Functional foods with supplementation of plant sterols are already used by millions of people. However, at the same time it is current scientific thinking that elevation of plant sterols in the circulation causes coronary heart disease. Therefore, this study aimed to define the risk for coronary heart disease associated with moderately high plant sterol plasma levels in a cohort of elderly. In this study, we evaluated the association between plant sterols and coronary heart disease in a cohort of 1242 subjects older than 65 years, participating at the Longitudinal Aging Study Amsterdam (LASA). Concentrations of sitosterol, campesterol, brassicasterol and stigmasterol were assessed using highly sensitive and specific gas chromatography-mass spectrometry-selected ion-monitoring. Plant sterol concentrations (and their ratios to cholesterol) were slightly, however, significantly lower in patients with coronary heart disease. Moreover, high plasma concentrations of a marker plant sterol, sitosterol, were associated with a markedly reduced risk for coronary heart disease (OR 0.78, CI 0.62-0.98, p<0.05). In contrast neither plant stanols (sitostanol or campestanol) nor the cholesterol synthesis markers (lathosterol, lanosterol and desmosterol) nor their ratios to cholesterol were significantly different in the study groups. These data suggest that plant sterols could have neutral or even protective effects on development of coronary heart disease, which have to be confirmed in interventional trials.

Aged↗
PubMed2006

Steroid structural requirements for interaction of ostreolysin, a lipid-raft binding cytolysin, with lipid monolayers and bilayers.

Ostreolysin, a cytolytic protein from the edible oyster mushroom (Pleurotus ostreatus), recognizes and binds specifically to membrane domains enriched in cholesterol and sphingomyelin (or saturated phosphatidylcholine). These events, leading to permeabilization of the membrane, suggest that a cholesterol-rich liquid-ordered membrane phase, which is characteristic of lipid rafts, could be its possible binding site. In this work, we present effects of ostreolysin on membranes containing various steroids. Binding and membrane permeabilizing activity of ostreolysin was studied using lipid mono- and bilayers composed of sphingomyelin combined, in a 1/1 molar ratio, with natural and synthetic steroids (cholesterol, ergosterol, beta-sitosterol, stigmasterol, lanosterol, 7-dehydrocholesterol, cholesteryl acetate, and 5-cholesten-3-one). Binding to membranes and lytic activity of the protein are both shown to be dependent on the intact sterol 3beta-OH group, and are decreased by introducing additional double bonds and methylation of the steroid skeleton or C17-isooctyl chain. The activity of ostreolysin mainly correlates with the ability of the steroids to promote formation of liquid-ordered membrane domains, and is the highest with cholesterol-containing membranes. Furthermore, increasing the cholesterol concentration enhanced ostreolysin binding in a highly cooperative manner, suggesting that the membrane lateral distribution and accessibility of the sterols are crucial for the activity of this new member of cholesterol-dependent cytolysins.

Calorimetry, Differential Scanning↗
PubMed2004

Plant sterols as selective DNA polymerase beta lyase inhibitors and potentiators of bleomycin cytotoxicity.

In a survey of crude plant extracts for DNA polymerase beta lyase inhibitors, the hexanes extracts of Cladogynus orientalis, Hymenache donacifolia, and Heteropsis integerrima, and the methyl ethyl ketone extract of Acacia pilispina were found to exhibit good inhibition of the dRP lyase activity of DNA polymerase beta. Bioassay-guided fractionation of these extracts led to the isolation of three DNA polymerase beta lyase inhibitory phytosterols, namely stigmasterol (1) and beta-sitosterol (2), isolated from the hexanes extracts, and beta-sitosterol-beta-d-glucoside (3), isolated from the methyl ethyl ketone extract. Compounds 1-3 inhibited the DNA polymerase beta lyase activity with IC(50) values of 43.6, 43.3, and 72.4 microM, respectively. Compounds 1 and 2 were found capable of potentiating the action of bleomycin in cultured human tumor cells, consistent with the possibility that lyase inhibitors may find utility in vivo.

Base Sequence↗
PubMed2004

New lupane triterpenoids from Solidago canadensis that inhibit the lyase activity of DNA polymerase beta.

Bioassay-directed fractionation of a methyl ethyl ketone extract of Solidago canadensis L. (Asteraceae), using an assay to detect the lyase activity of DNA polymerase beta, resulted in the isolation of the four new lupane triterpenoids 1-4 and the seven known compounds lupeol, lupeyl acetate, ursolic acid, cycloartenol, cycloartenyl palmitate, alpha-amyrin acetate, and stigmasterol. The structures of the new compounds were established as 3beta-(3R-acetoxyhexadecanoyloxy)-lup-20(29)-ene (1), 3beta-(3-ketohexadecanoyloxy)-lup-20(29)-ene (2), 3beta-(3R-acetoxyhexadecanoyloxy)-29-nor-lupan-20-one (3), and 3beta-(3-hetohexadecanoyloxy)-29-nor-lupan-20-one (4), respectively, on the basis of extensive 1D and 2D NMR spectroscopic interpretation and chemical modification studies. All 11 compounds were inhibitory to the lyase activity of DNA polymerase beta.

DNA Polymerase beta↗
PubMed2005

Structure-function relationship for saponin effects on cell cycle arrest and apoptosis in the human 1547 osteosarcoma cells: a molecular modelling approach of natural molecules structurally close to diosgenin.

In this paper, eight natural molecules structurally close to diosgenin (five saponins: diosgenin, hecogenin, tigogenin, sarsasapogenin, smilagenin; two steroidal alkaloids: solasodine, solanidine; one sterol: stigmasterol) have been tested for their biological activities on human 1547 osteosarcoma cells. Differences in activity were studied in term of proliferation rate, cell cycle distribution and apoptosis induction. By using molecular modelling, two structural characteristics were calculated: spatial conformation and electron transfer capacity. The second property has been investigated by the HOMO repartition and the corresponding energy. Correlation between the experimental and the theoretical data permit us to highlight the importance of the hetero-sugar moiety and the 5,6-double bond in the biological activity (apoptosis and cell cycle arrest) on the human 1547 cell line. The importance of conformation at C-5 and C-25 carbon atoms was also discussed.

Apoptosis↗