Triterpene alcohols and sterols of vegetable oils

Antidiabetes constituents, cycloartenol and 24-methylenecycloartanol, from Ficus krishnae

Ficus krishnae stem bark and leaves are used for diabetes treatment in traditional medicines. Stem bark of F. krishnae was sequentially extracted with hexane, methanol and water, and these extracts were tested for their antihyperglyceamic activity by oral glucose tolerance test (OGTT) in overnight fasted glucose loaded normal rats. Hexane extract showed significant glucose lowering activity in OGTT, and the triterpene alcohols (cycloartenol+24-methylenecycloartanol) (CA+24-MCA) were isolated together from it by activity guided isolation and characterized by NMR and mass spectroscopy. The ratio of the chemical constituents CA and 24-MCA in (CA+24-MCA) was determined as 2.27:1.00 by chemical derivatization and gas chromatographic quantification. (CA+24-MCA) in high fat diet-streptozotocin induced type II diabetic rats showed significant antidiabetes activity at 1 mg/kg and ameliorated derailed blood glucose and other serum biochemical parameters. Cytoprotective activity of (CA+24-MCA) from glucose toxicity was evaluated in cultured RIN-5F cells by MTT assay and fluorescent microscopy. (CA+24-MCA) in in vitro studies showed enhanced cell viability in RIN-5F cells and significant protection of beta cells from glucose toxicity. Both in in vivo and in vitro studies (CA+24-MCA) showed enhancement in insulin release from the beta cells. In short term toxicity studies in mice (CA+24-MCA) did not show any conspicuous toxic symptoms. The combination of the phytosterols (CA+24-MCA) obtained through activity guided isolation of the stem bark of F. krishnae showed significant activity, and therefore is a promising candidate for new generation antidiabetes drug development.

Does unsaponifiable fraction of grape seed oil attenuate nitric oxide production, oxidant and cytotoxicity activities

Triterpenoids, tocopherols, and phytosterols presented in unsaponifiable fraction of grape seed oil have several beneficial effects comprising antioxidant, anti-inflammatory, and antitumor capacities. In this study, the unsaponifiable fraction of three Tunisian grape seed varieties (Vitis vinifera L.), namely Merlot, Carignan, and Syrah, was investigated. The identified compounds were two triterpenic compounds (β-amyrin, lanosterol), six phytosterols (campesterol, ∆⁷ -avenasterol, stigmasterol, β-sitosterol, β-sitostanol, cholesterol), and three tocopherols (α, β, and γ tocopherols). The unsaponifiable fraction had significant protection against oxidative damage by modulating NO production and antioxidant activity. Statistical analysis showed the presence of three clusters of varieties associated to specific composition patterns. These results clearly demonstrated that unsaponifiable fraction profiles of grape species could be considered as a complementary data to the existing taxonomic evidence and classification purposes. PRACTICAL APPLICATIONS: Recently, much attention has been focused to substitute artificial antioxidant by others originating from natural products as plant matrices. The unsaponifiable fraction of grape seed oils is an interesting source of bioactive components like phytosterols, tocopherols, triterpenoids, and other various components. These components are known for their antitumor, anti-inflammatory and antioxidant capacities.

Effect of plant-based diets with varying ratios of ω6 to ω3 fatty acids on growth performance, tissue composition, fatty acid biosynthesis and lipid-related gene expression in Atlantic salmon (Salmo salar)

Little is known about how variation in omega-6 to omega-3 (ω6:ω3) fatty acid (FA) ratios affects lipid metabolism and eicosanoid synthesis in salmon, and the potential underlying molecular mechanisms. The current study examined the impact of five plant-based diets (12-week exposure) with varying ω6:ω3 (0.3-2.7) on the growth, tissue lipid composition (muscle and liver), and hepatic transcript expression of lipid metabolism and eicosanoid synthesis-related genes in Atlantic salmon. Growth performance and organ indices were not affected by dietary ω6:ω3. The liver and muscle FA composition was highly reflective of the diet (ω6:ω3 of 0.2-0.8 and 0.3-1.9, respectively) and suggested elongation and desaturation of the ω3 and ω6 precursors 18:3ω3 and 18:2ω6. Furthermore, proportions of ω6 and ω3 PUFA in both tissues showed significant positive correlations with dietary inclusion (% of diet) of soy and linseed oils, respectively. Compound-specific stable isotope analysis (CSIA) further demonstrated that liver long-chain polyunsaturated fatty acid (LC-PUFA) synthesis (specifically 20:5ω3 and 20:4ω6) was largely driven by dietary 18:3ω3 and 18:2ω6, even when 20:5ω3 and 22:6ω3 were supplied at levels above minimum requirements. In addition, significant positive and negative correlations were identified between the transcript expression of LC-PUFA synthesis-related genes and liver ω6 and ω3 LC-PUFA, respectively, further supporting FA biosynthesis. Liver ω3 LC-PUFA also correlated negatively with the eicosanoid synthesis-related transcripts pgds and cox1. This is the first study to use CSIA, hepatic transcriptome, and tissue lipid composition analyses concurrently to demonstrate the impact of plant-based diets with varying ω6:ω3 on farmed Atlantic salmon.

Ecological and Phytochemical Studies on Euphorbia retusa (Forssk.) from Egyptian Habitat

This study deals with the ecology, phytochemistry, and biological activity investigation of Euphorbia retusa, belonging to Euphorbiaceae family, obtained from Egypt. Ecologically, Euphorbia retusa secretes white sap inhibiting the growth of the other species, so Euphorbia retusa is forming complete patches. Phytochemical study of the plant was visualized intensively based on its extraction with a protic organic solvent, working up and purifying its entire bioactive compounds using a series of different chromatographic techniques. A broad range of diverse compounds were isolated, namely, 1-hexacosanol (1), 3β-hydroxy-24-methylene-9,19-cyclolanostane; 24-methylenecycloartanol (2), 3β-hydroxy-9,19-cyclolanostane; cyclolaudanol (3), 3β,24S-Ergost-5-en-ol (4), and methyllinoleate. Additionally, GC-MS analysis of the unpolar fractions detected the existence of n-dodecane, methyllaurate, 6,10,14-trimethyl-pentadecan-2-one (5), 6,10-dimethyl-undecan-2-one (6), 2-methyl-hexadecanal (7), methylpalmitate, methyl-9,12,15-octadecatrienoate (8), and n-heneicosane (9). A full assignment for compounds 2 and 3 using 1 and 2 DNMR was carried out herein for the first time. The antimicrobial activity of the strain extract and obtained compounds was studied using a panel of pathogenic bacterial strains. The in vitro cytotoxicity of the compounds as well as the crude extract was studied against the human cervix carcinoma cell line (KB-3-1).

Nonglyceride Components of Edible Oils and Fats. 1. Chemistry and Distribution

Dietary fats and oils are essentially glycerides of fatty acids (triglycerides), which account for 90% to 98% of their mass. The remaining 2% to 10% consists of fat-soluble phytochemicals derived from oil-bearing seeds, nuts, or fruits. These nonglyceride components of fats and oils represent a wide range of chemical classes, such as sterols, terpene alcohols, tocopherols, hydrocarbons, long-chain alcohols including waxes, carotenoid pigments, and sulfur- and nitrogen-containing flavor compounds. Each of these classes of chemicals consists of a number of different compounds. Their number and type and the quantity present vary from one oil to another. Modern analytical tools developed in recent decades have enabled separation and identification of the individual chemicals of each class in a number of oils. The nonglyceride chemical components of oils pass into the unsaponifiable fraction as such or in a modified form. There is still a gap in our knowledge concerning the identity and nature of several of these chemicals in the nonglyceride components, particularly in some of the unconventional edible oils. Earlier, these nonglyceride components were considered adventitious chemicals. For the past two decades, however, it has been recognized that many of them have nutritional and physiological functions that have been proved by animal and human studies to be useful in preventing noncommunicable diseases and promote health. The nonglyceride components of edible oils (i.e., palm, rice bran, and sesame oils) are particularly rich in such health-promoting chemicals.

Sitosterolemia: a gateway to new knowledge about cholesterol metabolism

Sitosterolemia (OMIM 210250) is a rare, autosomal recessive lipid disorder initially described almost 30 years ago. The disease is characterized by elevated plasma levels of plant sterols due to increased intestinal absorption and reduced biliary secretion of neutral sterols. Patients with sitosterolemia are frequently hypercholesterolemic, and develop xanthomas and premature coronary heart disease (CHD). Hemolysis, arthralgias and arthritis are also frequently associated with the disorder. Recently, sitosterolemia has been revealed to be due to mutations in either of the two ATP-binding cassette (ABC) half-transporters. ABCG5 or ABCG8. These two genes are expressed almost exclusively in the liver and intestine, and are co-regulated by the nuclear hormone receptor, liver X receptor (LXR). Genetically modified mice, which express either high levels or no ABCG5 and ABCG8 have been developed. Analyses of these mice confirm that these two transporters play key roles in regulating the absorption of dietary and biliary sterols, and in mediating the excretion of neutral sterols from the liver to the bile. The elucidation of the gene defects responsible for sitosterolemia provides potential therapeutic targets for the treatment of hyperlipidemias in the general population.

The sterols of Cucurbita moschata ("calabacita") seed oil

From the sterol fraction of seed oil from commercial Cucurbita moschata Dutch ("calabacita") delta 5 and delta 7 sterols having saturated and unsaturated side chain were isolated by chromatographic procedures and characterized by spectroscopic (1H and 13C-nuclear magnetic resonance, mass spectrometry) methods. The main components were identified as 24S-ethyl 5 alpha-cholesta-7,22E-dien-3 beta-ol (alpha-spinasterol); 24S-ethyl 5 alpha-cholesta-7,22E,25-trien-3 beta-ol (25-dehydrochondrillasterol); 24S-ethyl 5 alpha-cholesta-7,25-dien-3 beta-ol; 24R-ethyl-cholesta-7-en-3 beta-ol (delta 7-stigmastenol) and 24-ethyl-cholesta-7, 24(28)-dien-3 beta-ol (delta 7,24(28)-stigmastadienol).

Chromatographic separation of cholesterol in foods

Based on the current literature and on experience gained in the laboratory, a simplified procedure using direct saponification (0.4 M potassium hydroxide in ethanol and heating at 60 degrees C for 1 h) is the most appropriate method for the determination of total cholesterol in foods. Extraction of the unsaponifiable matter with hexane is efficient and no extra clean-up is required before quantification. An internal standard, 5 alpha-cholestane or epicoprostanol, should be added to the sample prior to saponification and, together with reference standards, carried through the entire procedure to ensure accurate results. A significant improvement in cholesterol methodology has been achieved by decreasing the sample size and performing all the sample preparation steps in a single tube. The method has the advantages of elimination of an initial solvent extraction for total lipids and errors resulting from multiple extractions, transfers, filtration and wash steps after saponification. The resulting hexane extract, which contains a variety of sterols and fat soluble vitamins, requires an efficient capillary column for complete resolution of cholesterol from the other compounds present. The development of fused-silica capillary columns using cross-linked and bonded liquid phases has provided high thermal stability, inertness and separation efficiency and, together with automated cold on-column gas chromatographic injection systems, has resulted in reproducible cholesterol determinations in either underivatized or derivatized form. If free cholesterol and its esters need to be determined separately, they are initially extracted with other lipids with chloroform-methanol followed by their separation by column or thin-layer chromatography and subsequently analysed by gas or liquid chromatography. Although capillary gas chromatography offers superior efficiency in separation, the inherent benefits of liquid chromatography makes it a potential alternative. Isotope dilution mass spectrometry has been widely accepted as a reliable analytical method for highly accurate determination of cholesterol in serum and several definitive methods have been reported. The combination of capillary gas chromatography with mass spectrometry has become an excellent approach for the determination of cholesterol in complex mixtures of sterols and tocopherols, providing high resolution with positive identification. When used to determine cholesterol in multi-component foods, spectrophotometric methods have been documented to overestimate significantly the amount of cholesterol owing to the presence of other interfering substances. A re-evaluation of food products should be undertaken using the more specific chromatographic methods to accumulate data that will more accurately reflect the true cholesterol content.

The content and composition of sterols and sterol esters in sunflower and poppy seed oils

The composition and proportion of free sterols and sterol esters in crude sunflower and poppy seed oils were determined, using preparative thin layer chromatography followed by gas chromatography with cholesterol as an internal standard. Free sterols and sterols esters were also isolated in a liquid fraction obtained by low temperature crystallization (-80 C) of the oils and enriched with minor lipid classes. This enrichment procedure provided a liquid fraction suitable for studies of minor components in the oils. However, selectivity towards sterol esters was observed since sterols esterified to very long chain fatty acids (C20-C24) were preferentially retained in the precipitate. The proportion of free and esterified sterols were found to be 0.34% and 0.28%, respectively, in the sunflower oil, whereas the corresponding figures for poppy seed oil were 0.33% and 0.05%. Sunflower oil was characterized by a relatively high percentage of delta 7-sterols, preferentially obtained in the esterified fraction, and by very long chain saturated fatty acids of sterol esters. The sterols in poppy seed oil were composed almost entirely of campesterol, stigmasterol, sitosterol and delta 5-avenasterol, although their percentage distributions were remarkably different in the free and esterified fraction.

Fecal beta-sitosterol in patients with diverticular disease of the colon and in vegetarians

Fecal sterol analysis showed that excretion of beta-sitosterol, a major component of poorly absorbable dietary vegetable sterols, is subnormal in patients with diverticular disease of the colon. Thus, the patients had evidently consumed a diet low in plant materials. The finding agrees with the current opinion that diverticular disease of the colon is associated with dietary fibre deficiency and suggests that fecal beta-sitosterol provides a rough measure of the vegetable intake. In vegetarians the beta-sitosterol excretion was actually high.

Sterol composition of Bulgarian soya and corn oils

The free sterols, the sterol esters and the sterol glycosides of the raw soya and corn oils as well as those of the technical lecithin and the deodorizer distillated of the latter oils were isolated by preparative TLC. The composition of each of the isolated sterol derivatives was determined by GLC and MS. Sitosterol, campesterol, stigmasterol and an unknown sterol with a molecular weight of 428 are contained in almost all of the examined fractions of the soya oil and its refinement byproducts. Dehydrocampesterol is present in the free sterols of the raw soya oil and the soya lecithin. Stigmasterol is contained in the soya deodorizer distillate in high amounts. It was established that cholesterol was present in the sterol esters of the raw soya oil high amounts. Delta7-stigmastenol occurs only in the sterol esters of the latter oil. Sitosterol, campesterol and stimgasterol are the main components of all sterol fractions of the corn oil and its refinement products. Dehydrocampesterol and unknown sterols with molecular weights of 428 are present in the free sterols of the raw corn oil. Some sterol glycosides of the soya and corn lecithin are esterified with the same major fatty acid components of the glycerides, palmitic acid being the main one. The fatty acid compositon of sterol esters of the raw soya and corn oil roughly corresponds to the fatty acid composition of oils.

[Free and bound sterol content of sunflower, soy bean and maize oils]

The amounts of free sterols, steryl esters and steryl glycosides in sunflower, soya and maize oils as well as in the phosphatides of the same oils were determined. The refinement byproducts were enriched with sterols. The highest contents of total sterols and steryl glycosides (2,68 and 1,9%, respectively) were established in soya phosphatides followed by those in sunflower oil phosphatides (2,03 and 1,68%, respectively) and maize oil phosphatides (0,81 and 0,54%, respectively).