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At least 19 recordsLinked to original sources
PubMed2006

Stigmasterol reduces plasma cholesterol levels and inhibits hepatic synthesis and intestinal absorption in the rat.

Plant sterols compete with cholesterol (cholest-5-en-3beta-ol) for intestinal absorption to limit absorption and lower plasma concentrations of cholesterol. Stigmasterol (24-ethyl-cholesta-5,22-dien-3beta-ol; Delta(22) derivative of sitosterol [24-ethyl-cholest-5-en-3beta-ol]), but not campesterol (24-methyl-cholest-5-en-3beta-ol) and sitosterol, is reported to inhibit cholesterol biosynthesis via inhibition of sterol Delta(24)-reductase in human Caco-2 and HL-60 cell lines. We studied the effect of feeding 0.5% stigmasterol on plasma and liver sterols and intestinal cholesterol and sitosterol absorption in 12 wild-type Kyoto (WKY) and 12 Wistar rats. After 3 weeks of feeding, cholesterol and sitosterol absorption was determined in 6 rats from each group by plasma dual-isotope ratio method. After 3 more weeks, plasma and hepatic sterols and hepatic enzyme activities were determined in all rats. After feeding stigmasterol, baseline plasma cholesterol was 1.3 times and plant sterols 3 times greater in WKY compared with Wistar rats. Stigmasterol feeding lowered plasma cholesterol by approximately 11%, whereas plasma campesterol and sitosterol levels were virtually unchanged in both rat strains, and stigmasterol constituted 3.2% of plasma sterols in WKY rats and 1% in Wistar rats. After 6 weeks of feeding, cholesterol and sitosterol absorption decreased 23% and 30%, respectively, in WKY, and 22% and 16%, respectively, in the Wistar rats as compared with untreated rats. The intestinal bacteria in both rat strains metabolized stigmasterol to mainly the 5beta-H stanol (>40%), with only small amounts of 5alpha-H derivative (approximately 1.5%), whereas the C-22 double bond was resistant to bacterial metabolism. Hepatic stigmasterol levels increased from 11 microg/g liver tissue to 104 mug/g in WKY rats and from 5 microg/g liver tissue to 21 microg/g in Wistar rats. 3-Hydroxy-3-methylglutaryl coenzyme A reductase activity was suppressed 4-fold in the WKY and almost 1.8-fold in Wistar rats, cholesterol 7alpha-hydroxylase activity was suppressed 1.6-fold in the WKY and 3.5-fold in Wistar rats, whereas cholesterol 27-hydroxylase activity was unchanged after feeding. In conclusion, stigmasterol, when fed, lowers plasma cholesterol levels, inhibits intestinal cholesterol and plant sterol absorption, and suppresses hepatic cholesterol and classic bile acid synthesis in Wistar as well as WKY rats. However, plasma and hepatic incorporation of stigmasterol is low.

Animals↗
PubMedDate not supplied

Inhibition of stigmasterol oxidation by antioxidants in purified sunflower oil.

A study was conducted to analyze the effect of the antioxidants butylated hydroxytoluene, alpha-tocopherol, ethanolic extracts of rosemary, and green tea on stigmasterol resistance against degradation and formation of its oxidation products in purified triacylglycerols (TAG) from sunflower oil. The content of stigmasterol and its oxidation products 7alpha- and 7beta-hydroxy, alpha- and beta-epoxy, triol, and 7-ketostigmasterol were determined during incubation at 60 degrees C for 3, 6, and 9 days. In addition, peroxide value and fatty acid composition were also determined in the samples. Correlation between the levels of the accumulated stigmasterol oxides and peroxide value of the TAG with antioxidants during incubation was significant only for rosemary extract (R = 0.6799, p < 0.05). The lack of correlation precludes the use of peroxide values to determine the level of sterol oxidation products in the used model system. Correlation between stigmasterol content and the level of stigmasterol oxides was significant for all samples (R = 0.8874, p < 0.05). The total increase of the stigmasterol oxidation products was the lowest in samples with alpha-tocopherol, but the content of stigmasterol-triol increased the most in this sample. In all the analyzed samples, alpha-epoxy-stigmasterol was formed in the highest amounts among the analyzed stigmasterol oxidation products.

Antioxidants↗
PubMedDate not supplied

Intermediates of stigmasterol metabolism in Spodoptera littoralis.

Stigmasterol-24,28-epoxide, 22E-stigmasta-5,22,24(28E)-trien-3 beta-ol, and 22E-cholesta-5,22,24-trien-3 beta-ol were identified as normal metabolites of [3H]stigmasterol in Spodoptera littoralis larvae. Relative concentrations of all three of these metabolites increased when a diazasterol inhibitor was fed in combination with stigmasterol in the artificial diet. Identification of these sterols as intermediates in the conversion of stigmasterol to cholesterol in this insect indicates that intermediates analogous to fucosterol and fucosterol-24,28-epoxide in the conversion of sitosterol to cholesterol are produced in the metabolism of stigmasterol. This is the first published identification of stigmasterol-24,28-epoxide and 22E-stigmasta-5,22,24(28E)-trien-3 beta-ol as intermediates in this pathway in an insect.

Animals↗
PubMed2001

Liquid chromatography-UV determination and liquid chromatography-atmospheric pressure chemical ionization mass spectrometric characterization of sitosterol and stigmasterol in soybean oil.

A narrow-bore HPLC-UV method was developed for the analysis of two of the more abundant naturally occurring phytosterols in vegetable oils: sitosterol and stigmasterol. The method enabled detection of the compounds at a concentration of 0.42 microg/ml and quantitation at concentrations of 0.52 and 0.54 microg/ml for sitosterol and stigmasterol, respectively. An excellent linearity was determined over two orders of concentration magnitude (r2 0.999-1.000) and verified by applying the Mandel fitting test (p>0.099) and the lack-of-fit test (p>0.057) performed at the 95% confidence level. A good intra-day precision ranging from 0.15 to 1.16% was calculated at two concentration levels (2 and 100 microg/ml). The inter-day reproducibility was verified on 3 different days by performing an homoscedasticity test and analysis of variance. A solid-phase extraction method was developed on silica cartridges for the isolation of phytosterols from soybean oil providing recovery values of 101+/-9 and 106+/-7% for sitosterol and stigmasterol, respectively. Good accuracy of the method was statistically demonstrated since no matrix effect was found for both the analytes. The developed method was applied to the quantitative assay of phytosterols in a soybean oil sample (61+/-5 mg/100 g of stigmasterol and 118+/-4 mg/100 g sitosterol). The HPLC-atmospheric pressure chemical ionization MS technique enabled the identification of stigmasterol, sitosterol and campesterol in the oil sample.

Atmospheric Pressure↗
PubMed1998

Plant sterols: a neutron diffraction study of sitosterol and stigmasterol in soybean phosphatidylcholine membranes.

Neutron scattering experiments have been performed on oriented Soybean phosphatidylcholine (SPC) bilayers, containing sitosterol or stigmasterol, two major sterols of plant plasma membranes. Sitosterol and stigmasterol were either protonated or deuterated on position C25 of the lateral chain. Incorporation of sitosterol leads to an increase of the hydrophobic thickness of SPC bilayers of 1.2 and 2 A when present, at 16 and 30 mol%, respectively. On the other hand, no change was observed when stigmasterol is present in the bilayer at its maximal solubility of 16 mol%. These results are in agreement with the fact that sitosterol is more efficient than stigmasterol to order acyl chains of SPC, as already shown with other biophysical techniques. In order to get more insight into the behavior of the lateral chains of the two sterols, the proton-deuterium contrast method was used in order to locate the (2)H25 atoms of the two sterols. For sitosterol, this atom was found close to the center of the bilayer at +/-(1.6+/-0.2 A), with a width, nu=2.5+/-0.5 A. For stigmasterol, the difference profile could be fitted in two different ways: either two possible locations are found at +/-(2.3+/-0.2 A) and +/-(10+/-0.2 A) with the same width, nu=2.5+/-0.5 A or only one broad distribution at +/-(6.1+/-0.3 A), nu=8.5+/-0.7 A. The results are discussed in terms of difference of dynamics for the lateral chain of the two sterols.

Journal Article↗
PubMed1989

Effects of stigmasterol-supplemented diets on fecal neutral sterols and bile acid excretion in rats.

To study the effects of dietary stigmasterol on sterol and bile acids metabolism, Wistar rats were fed diets containing various amounts of stigmasterol. Feeding high stigmasterol doses (11, 26 or 52 mg/day) led to increased cholesterol, coprostanol and bile acid output. These effects were dose-dependent, and likely to be related to the inhibitory effect of plant sterols on cholesterol absorption. Moreover, it accounts for the beneficial effect of the stigmasterol on cholesterol lowering.

Animals↗
PubMedDate not supplied

Determination of campesterol, stigmasterol, and beta-sitosterol in saw palmetto raw materials and dietary supplements by gas chromatography: single-laboratory validation.

In conjunction with an AOAC Presidential Task Force on Dietary Supplements, a method was validated for measurement of 3 plant sterols (phytosterols) in saw palmetto raw materials, extracts, and dietary supplements. AOAC Official Method 994.10, "Cholesterol in Foods," was modified for purposes of this validation. Test samples were saponified at high temperature with ethanolic potassium hydroxide solution. The unsaponifiable fraction containing phytosterols (campesterol, stigmasterol, and beta-sitosterol) was extracted with toluene. Phytosterols were derivatized to trimethylsilyl ethers and then quantified by gas chromatography with a hydrogen flame ionization detector. The presence of the phytosterols was detected at concentrations greater than or equal to 1.00 mg/100 g based on 2-3 g of sample. The standard curve range for this assay was 0.00250 to 0.200 mg/mL. The calibration curves for all phytosterols had correlation coefficients greater than or equal to 0.995. Precision studies produced relative standard deviation values of 1.52 to 7.27% for campesterol, 1.62 to 6.48% for stigmasterol, and 1.39 to 10.5% for beta-sitosterol. Recoveries for samples fortified at 100% of the inherent values averaged 98.5 to 105% for campesterol, 95.0 to 108% for stigmasterol, and 85.0 to 103% for beta-sitosterol.

Calibration↗
PubMed1979

Antihypercholesterolemic studies with sterols: beta-sitosterol and stigmasterol.

Stigmasterol, which differs from beta-sitosterol by unsaturation at C22, was tested for antihypercholesterolemic activity under an experimental protocol that gave the results expected with beta-sitosterol and cholestyramine. In terms of serum cholesterol, stigmasterol had a barely significant antihypercholesterolemic effect while exhibiting no obvious effect on the heart or liver. It was concluded that saturation of the side chain, at least at C22, is important in conferring antihypercholesterolemic activity on a sterol.

Animals↗
PubMed1995

Microbial transformation of beta-sitosterol and stigmasterol into 26-oxygenated derivatives.

The genetically modified Mycobacterium sp. BCS 396 strain has been used to transform sterols with stigmastane side chain in order to obtain 26-oxidized metabolites. beta-Sitosterol (I) was transformed to 4-stigmasten-3-one (II), 26-hydroxy-4-stigmasten-3-one (III), and 3-oxo-4-stigmasten-26-oic acid (IV), while stigmasterol (V) was converted to 4,22-stigmastadien-3-one (VI), 6 beta-hydroxy-4,22-stigmastadien-3-one (VII), 26-hydroxy-4,22-stigmastadien-3-one (VIII), 3-oxo-4,22-stigmastadien-26-oic acid methyl ester (IX), and 3-oxo-1,4,22-stigmastatrien-26-oic acid methyl ester (X) with that strain. In both beta-sitosterol and stigmasterol, 26-oxidation generates the R-configuration on C-25.

Mass Spectrometry↗
PubMed2006

Phase diagram of stigmasterol-dipalmitoylphosphatidylcholine mixtures dispersed in excess water.

As a simple model of rafts in plant cells, the effect of stigmasterol, one of the predominant sterols in plant plasma membranes, on the phase behavior of dipalmitoylphosphatidylcholine (DPPC) multilayers has been studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and freeze-fracture electron microscopy (FFEM) techniques. A partial phase diagram of the binary system has been constructed. Particularly, the stigmasterol concentrations of the "left endpoint" and "right endpoint" of the three-phase line have been determined using the newly developed linear and nonlinear fitting method. They are 6.2 and 23.7 mol%, respectively. Furthermore, the resemblance and difference of phase diagrams of DPPC/stigmasterol, DPPC/cholesterol, and DPPC/ergosterol have been compared and the efficiency of these sterols in promoting the formation of the liquid-ordered domains (rafts) have also been discussed.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1999

Mass spectrometry characterization of the 5alpha-, 7alpha-, and 7beta-hydroxy derivatives of beta-sitosterol, campesterol, stigmasterol, and brassicasterol.

The 5alpha-hydroperoxides of beta-sitosterol, campesterol, stigmasterol, and brassicasterol were obtained by photooxidation of the respective sterols in pyridine in the presence of hematoporphyrine as sensitizer. The reduction of the hydroperoxides gives the corresponding 5alpha-hydroxy derivatives. The 7alpha- and 7beta-hydroperoxides of the sterols were obtained by allowing an aliquot of the 5alpha-hydroperoxides to isomerize to 7alpha-hydroperoxides, which in turn epimerize to 7beta-hydroperoxides. The reduction gave the corresponding 7alpha- and 7beta-hydroxy derivatives. The 5alpha-, 7alpha-, and 7beta-hydroxy derivatives of beta-sitosterol, campesterol, stigmasterol, and brassicasterol were identified by comparing thin-layer chromatography mobilities, specific color reactions, and mass spectral data with those of the corresponding hydroxy derivatives of cholesterol, which were synthesized in the same manner. The phytosterols had the same behavior to photooxidation as cholesterol and, moreover, the different phytosterols photooxidized at about the same rate. The mass spectra of the trimethylsilyl ethers of the hydroxy derivatives of the phytosterols investigated and of the corresponding hydroxy derivatives of cholesterol have the same fragmentation patterns and similar relative ion abundances.

Cholestadienols↗
PubMed1983

Comparative lymphatic absorption of sitosterol, stigmasterol, and fucosterol and differential inhibition of cholesterol absorption.

Studies have been conducted on the lymphatic absorption of sitosterol (24 alpha-ethyl cholesterol), stigmasterol (delta 22, 24 alpha-ethyl cholesterol), and fucosterol (24-ethylidine cholesterol) when administered intragastrically to rats. In addition, the effect of each sterol on absorption of endogenous cholesterol has been assessed by including tracer cholesterol in the administered test emulsion. Analysis of 24-h lymph collections by GLC-mass spectrometry demonstrated that all three sterols were poorly absorbed to the extent of only 3 to 4% of the administered dose of 50 mg. In contrast, cholesterol absorption under similar conditions was about 42% of the administered dose. Administration of either sitosterol or stigmasterol resulted in an equally effective inhibition of cholesterol absorption (54%). Under identical conditions fucosterol had no effect on absorption of luminal cholesterol. The data suggest that the mechanism(s) for intestinal discrimination of sterols for absorption may be independent of the mechanism for interference with efficient cholesterol uptake by the intestine.

Absorption↗
PubMed2003

On the electrochemical characterization of ion-selective cellulose acetate membranes with and without stigmasterol liquid membranes.

Stigmasterol, a plant product, has been used as a surfactant to generate liquid membranes supported on a cellulose acetate matrix. Electrochemical characterization of the membrane has been attempted with a view to simulating its behavior with natural membranes by measuring membrane potentials and membrane conductance. The selectivity of cellulose acetate membrane kept in contact with magnesium chloride solutions of different mean concentrations has been found to change from anion to cation. Transport numbers have been estimated from membrane potential data. Permselectivity and fixed charge density values for the cellulose acetate membrane with and without stigmasterol have been determined from transport numbers. The variation of these parameters with concentration and pH has also been examined.

Journal Article↗
PubMedDate not supplied

Chonemorphine, stigmasterol, and ecdysterone: steroids isolated through bioassay-directed plant screening programs.

In a bioassay-directed screening programme of plants for the identification of active constituents the following steroids were isolated. Chonemorphine was identified as the antiamoebic and antitrichomonad principle of Chonemorpha fragrans. Stigmasterol from Coleus forskohlii and ecdysterone from Diploclisia glaucescens were inactive constituents isolated during the process of purifying the active principles of the plants. D. glaucescens roots are a high-yielding source (0.5% of the dry root weight) of ecdysterone.

Antiprotozoal Agents↗
PubMed2004

Preparation and mass spectrometry of 14 pure and 18O(2)-labeled oxidation products from the phytosterols beta-sitosterol and stigmasterol.

To lower cholesterol, phytosterols are currently introduced as food additives, where they may become oxidized. In addition, specific biological effects of oxyphytosterols are suggested by the recent molecular clarification of the phytosterol storage disease as a dysfunctional mutation of an active sterol reexporter potentially regulated by oxidized phytosterols. We therefore studied the hydroxybenzotriazole-mediated PbO(2)-driven oxidation of phytosterols and compared it to the oxidation of cholesterol. We prepared, identified, and purified standards of 14 oxidation products of two major phytosterols. The gas chromatographic mass spectrometric characteristics of the 7alpha- and 7beta-hydroxy-, 5alpha,6alpha-epoxy, 5beta,6beta-epoxy, 7keto-, 3beta,5alpha,6beta-trihydroxy-, 3keto-, and 7-dehydro-derivatives of beta-sitosterol and stigmasterol are presented. The method also provided a convenient access to prepare 18O-labeled oxyphytosterols of high chemical and isotopic purity and can easily be extended to further phytosterols and -stanols. This enables the gas chromatography-mass spectrometry analysis of oxyphytosterols and the study of their biological effects.

Hematoporphyrins↗
PubMed2006

Determination of stigmasterol, beta-sitosterol and stigmastanol in oral dosage forms using high performance liquid chromatography with evaporative light scattering detection.

A validated and repeatable high performance liquid chromatography (HPLC) method with online evaporative light scattering (ELSD) was developed for the analysis of two sterols, stigmasterol, beta-sitosterol and a stanol, stigmastanol, found to be common in many herbal formulations and health care supplements. The method is based on the separation of the three marker compounds on a C8 column (Phenomenex Luna, 5 microm, 150 mmx4.6 mm i.d.) using methanol:water (95:5 v/v) as the mobile phase, and a flow rate of 1 ml/min to separate all the marker compounds within 12 min. Cholesterol (50 microg/ml) was used as internal standard and methanol as the extraction solvent. The ELSD response parameters were optimised and the limits of detection (LOD) and quantification (LOQ) were calculated to be 2 and 5 microg/ml, respectively, which is more sensitive than obtained by photo diode array detection (5 and 7 microg/ml). Using ELSD, the percentage relative standard deviation (%R.S.D.) of intra-day and inter-day (3 days) precision for each marker was better than 3%, the accuracy data were within 97-103% and the recovery data were found to be within 95-107% for the five commercially available products examined. This method was used to assay commercially available products formulated as oral dosage forms purported to contain African Potato and associated sterols and stanol and proved to be suitable for the routine analysis and quality control of such products.

Administration, Oral↗
PubMed2004

Gradient enhanced selective experiments in the 1H NMR chemical shift assignment of the skeleton and side-chain resonances of stigmasterol, a phytosterol derivative.

The applicability of homonuclear gradient enhanced NMR experiments is demonstrated in the structure determination of steroid derivatives using stigmasterol as a model compound. High resolution 1H NMR spectra of steroids very often display well resolved multiplets usually in the low-field region, and these signals can be used as starting points in several selective NMR experiments to study scalar (J coupling), and dipolar (NOE) interactions. Selective excitation was carried out using a double pulsed-field gradient spin-echo sequence (DPFGSE) in which 180 degrees Gaussian pulses are sandwiched between sine shaped z-gradients. Scalar interactions were studied by homonuclear DPFGSE-COSY, DPFGSE-relay-COSY and DPFGSE-TOCSY experiments, while DPFGSE-NOESY was used to monitor spatial environment of the selectively excited proton. These methods provided unambiguous assignments for signals of the main skeleton and the side-chain of the steroid molecule. In addition, they allowed determination of the conformationally important homonuclear proton-proton coupling constants (J).

Magnetic Resonance Spectroscopy↗