phytosterols and 24-methylene-cycloartanol

Hyperglycemia is a major public health problem worldwide and there is increasing demand for prevention of postprandial hyperglycemia in diabetic, prediabetic, and healthy humans.. We investigated whether rice bran and triterpene alcohol and sterol preparation (TASP) lowered hyperglycemia in mice and humans. Brown rice and white rice supplemented with TASP lowered the postprandial hyperglycemia in humans. TASP and its components (cycloartenol [CA], 24-methylene cycloartanol, β-sitosterol, and campesterol) decreased postprandial hyperglycemia in C57BL/6J mice. Glucose transport into everted rat intestinal sacs and human HuTu80 cells transfected with sodium-glucose cotransporter-1 (SGLT1) was significantly reduced by the addition of CA. Intracellular localization analysis suggested that SGLT1 translocation to the apical plasma membrane was inhibited when the cells were treated with CA.. We demonstrated for the first time that TASP from rice bran lowered postprandial hyperglycemia in mice and humans. The smaller increase in blood glucose following TASP consumption may be due to the CA-induced decrease in glucose absorption from the intestine, which may be related to decreased membrane translocation of SGLT1.

Topics: Adult; Animals; Blood Glucose; Body Mass Index; Body Weight; Cell Line, Tumor; Cholesterol; Dietary Fiber; Humans; Hyperglycemia; Insulin; Male; Mice; Mice, Inbred C57BL; Oryza; Phytosterols; Rats; Rats, Wistar; Single-Blind Method; Sitosterols; Sodium-Glucose Transporter 1; Sterols; Triterpenes

Obesity is now a worldwide health problem. Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone that is secreted following the ingestion of food and modulates energy metabolism. Previous studies reported that lowering diet-induced GIP secretion improved energy homeostasis in animals and humans, and attenuated diet-induced obesity in mice. Therefore, food-derived GIP regulators may be used in the development of foods that prevent obesity. Rice bran oil and its components are known to have beneficial effects on health. Therefore, the aim of the present study was to clarify the effects of the oil-soluble components of rice bran on postprandial GIP secretion and obesity in mice. Triterpene alcohols [cycloartenol (CA) and 24-methylene cycloartanol (24Me)], β-sitosterol, and campesterol decreased the diet-induced secretion of GIP in C57BL/6J mice. Mice fed a high-fat diet supplemented with a triterpene alcohol and sterol preparation (TASP) from rice bran for 23 wk gained less weight than control mice. Indirect calorimetry revealed that fat utilization was higher in TASP-fed mice than in control mice. Fatty acid oxidation-related gene expression in the muscles of mice fed a TASP-supplemented diet was enhanced, whereas fatty acid synthesis-related gene expression in the liver was suppressed. The treatment of HepG2 cells with CA and 24Me decreased the gene expression of sterol regulatory element-binding protein (SREBP)-1c. In conclusion, we clarified for the first time that triterpene alcohols and sterols from rice bran prevented diet-induced obesity by increasing fatty acid oxidation in muscles and decreasing fatty acid synthesis in the liver through GIP-dependent and GIP-independent mechanisms.

Topics: Alcohols; Animals; Diet, High-Fat; Energy Metabolism; Fatty Acids; Gastric Inhibitory Polypeptide; Hep G2 Cells; Humans; Intra-Abdominal Fat; Liver; Male; Mice, Inbred C57BL; Obesity; Oryza; Phytosterols; Phytotherapy; Postprandial Period; Triterpenes; Weight Gain

The analysis of the total lipid fraction from the Sayali variety of olive oil was accomplished in the present investigation. Glyceridic, unsaponifiable and flavour fractions of the oil were isolated and identified using several analytical methods. Chromatographic techniques have proven to be suitable for these determinations, especially capillary gas chromatography. Gas chromatography coupled to mass spectrometry was successfully used to identify sterols, triterpenes alcohols, 4-monomethylsterols, aliphatic alcohols and aroma compounds in our samples. Furthermore, solid phase microextraction was used to isolate volatiles from the total lipid fraction. Results from the quantitative characterization of Sayali olive oil showed that oleic acid (77.4%) and triolein (47.4%) were the dominant glyceridic components. However, the main compounds of the unsaponifiable fraction were beta-sitosterol (147.5mg/100g oil), 24-methylene cycloartenol (146.4mg/100g oil) and hexacosanol (49.3mg/100g oil). Moreover, results showed that the aldehydic compounds were the major flavours present in Sayali olive oil.

Topics: Alcohols; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Fatty Acids; Fatty Alcohols; Flame Ionization; Gas Chromatography-Mass Spectrometry; Lipids; Oleic Acid; Olive Oil; Phytosterols; Plant Oils; Sitosterols; Sterols; Triglycerides; Triolein; Tunisia

A comparative study was performed to determine the free sterols content and composition during the development of three varieties of linseed (H52, O116 and P129). Seed samples were collected at regular intervals from 7 to 60 days after flowering (DAF). Ten compounds were identified: cholesterol, campesterol, brassicasterol, stigmasterol, beta-sitosterol, Delta5-avenasterol, cycloartenol; 24-methylene cycloartanol, obtusifoliol, citrostadienol. The maximum level of 4-desmethylsterols (1,515 mg/100g oil) was reached at 7 DAF in P129 variety. H52 had the highest level of 4-4 dimethylsterols (355 mg/100g oil) at 28 DAF. The greatest amount of 4-monomethylsterols (35 mg/100g oil) was detected in H52 at 14 DAF. During linseed development, beta sitosterol (830 mg/100g oil) was the major 4-desmethylsterols, followed by campesterol (564 mg/100g oil) and stigmasterol (265 mg/100g oil). Some of these compounds followed nearly the same accumulation pattern during linseed maturation.

Topics: Cholestadienols; Cholesterol; Chromatography, Thin Layer; Flax; Flowers; Gas Chromatography-Mass Spectrometry; Phytosterols; Seeds; Sitosterols; Species Specificity; Stigmasterol; Time Factors; Triterpenes

Preparative high-speed counter-current chromatography (HSCCC), as a continuous liquid-liquid partition chromatography with no solid support matrix, combined with evaporative light scattering detection (ELSD) was employed for systematic separation and purification of non-chromophoric chemical components from Chinese medicinal herb Adenophora tetraphlla (Thunb.), Fisch. Nine compounds, including alpha-spinasterol, beta-sitosterol, nonacosan-10-ol, 24-methylene cycloartanol, lupenone, 3-O-palmitoyl-beta-sitosterol, 3-O-beta-d-glucose-beta-sitosterol, eicosanoic acid and an unknown compound, were obtained. The compounds were all above 95% determined by high-performance liquid chromatography (HPLC)-ELSD, and their structures were identified by (1)H NMR and chemical ionization mass spectroscopy (CI-MS). The results demonstrate that HSCCC coupled with ELSD is a feasible and efficient technique for systematic isolation of non-chromophoric components from traditional medicinal herbs.

Topics: Campanulaceae; Chromatography, High Pressure Liquid; Countercurrent Distribution; Light; Phytosterols; Plant Roots; Sitosterols; Stigmasterol; Triterpenes

Epidendrum mosenii is a Brazilian medicinal plant, traditionally used to treat infective and dolorous processes. The present article reports a comparative study of the chemical and pharmacological aspects of different parts and seasons of this plant. The results demonstrate that 24-methylenecycloartanol (1), one of the main active principles present in this plant, is located practically in all the parts and during all seasons, but it is much more concentrated in the stems when collected in spring and summer. The pharmacological results indicate that dichloromethane extracts collected in spring and summer were the most active when evaluated against the writhing test in mice, being several times more potent than some reference drugs used as comparison. Together, the results strongly suggest that the antinociceptive effect of E. mosenii is related, at least in part, to the presence of compound 1, and this finding could be useful for quality control of phytopreparations based on this plant.

Topics: Analgesics; Animals; Brazil; Chromatography, Gas; Mice; Molecular Structure; Orchidaceae; Phytosterols; Plant Stems; Plants, Medicinal; Seasons

Microsomes isolated from corn embryos (Zea mays) were shown to catalyse the C-4 monodemethylation of 28-[3H],24-methylene cycloartanol 1, leading to the corresponding 4 alpha-methyl sterol, cycloeucalenol 5. An enzymatic assay has been developed for the 4,4-dimethyl sterol 4-demethylase in higher plants. The demethylation process was shown to involve a 4-methyl, 4-hydroxymethyl derivative 2 which can be considered as the immediate metabolite of 1 by the 4-methyl oxidase. Compound 2 is further metabolized into 5 through a 4-methyl-4-carboxylic acid 3 and a 3-keto-4 alpha-methyl intermediate 4 which were identified. The conversion of 1 into 5 requires NADPH and molecular oxygen. The initial oxidative step was strictly dependent upon molecular oxygen, NADPH or NADH, and strongly inhibited by cyanide, whereas the overall process was completely insensitive to CO and to specific inhibitors of cytochrome P-450. It is concluded that in Zea mays microsomes, the C-4 demethylation of 1 results from a multistep process involving a terminal oxygenation system sensitive to cyanide which is distinct from cytochrome P-450 and in particular from that involved in the 14 alpha-demethylation of obtusifoliol.

Topics: Cholesterol; Gas Chromatography-Mass Spectrometry; Microsomes; Oxidation-Reduction; Oxygenases; Phytosterols; Plants; Zea mays