| 1. |
- Albertsson, Per-Åke, et al.
(author)
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Chloroplast membranes retard fat digestion and induce satiety: effect of biological membranes on pancreatic lipase/co-lipase
- 2007
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In: Biochemical Journal. - 0264-6021. ; 401, s. 727-733
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Journal article (peer-reviewed)abstract
- Human obesity is a global epidemic, which causes a rapidly increased frequency of diabetes and cardiovascular disease. One reason for obesity is the ready availability of refined food products with high caloric density, an evolutionarily new event, which makes over-consumption of food inevitable. Fat is a food product with high caloric density. The mechanism for regulation of fat intake has therefore been studied to a great extent. Such studies have shown that, as long as fat stays in the intestine, satiety is promoted. This occurs through the fat-released peptide hormones, the best known being CCK (cholecystokinin), which is released by fatty acids. Hence, retarded fat digestion with prolonged time for delivery of fatty acids promotes satiety. Pancreatic lipase, together with its protein cofactor, co-lipase, is the main enzymatic system responsible for intestinal fat digestion. We found that biological membranes, isolated from plants, animals or bacteria, inhibit the lipase/co-lipase-catalysed hydrolysis of triacylglycerols even in the presence of bile salt. We propose that the inhibition is due to binding of lipase/co-lipase to the membranes and adsorption of the membranes to the aqueous/triacylglycerol interface, thereby hindering lipase/co-lipase from acting on its lipid substrate. We also found that chloroplast membranes (thylakoids), when added to refined food, suppressed food intake in rats, lowered blood lipids and raised the satiety hormones, CCK and enterostatin. Consequently, the mechanism for satiety seems to be retardation of fat digestion allowing the fat products to stay longer in the intestine.
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| 2. |
- Emek, Sinan C, et al.
(author)
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A large scale method for preparation of plant thylakoids for use in body weight regulation.
- 2010
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In: Preparative biochemistry & biotechnology. - : Informa UK Limited. - 1532-2297 .- 1082-6068. ; 40:1, s. 13-27
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Journal article (peer-reviewed)abstract
- A method for preparation of thylakoids from plant leaves on a large scale is described. The method involves: 1) disruption of the cells with a blender followed by filtration to remove large cell debris and non disrupted cells. 2) precipitation of the thylakoids by adjusting the pH to the isoelectric point, pH 4.7. 3) a washing step by dilution of the precipitate in water followed by precipitation at the same pH. 4) concentration of the precipitate by freeze- thawing or freeze -drying to get the final product. The product is characterized, with respect to protein composition, by SDS-PAGE and mass-spectroscopy, the content of carotenoids, particularly the xanthophylls violaxanthin, antheraxanthin, and zeaxanthin. The thylakoid preparation has about the same capacity to inhibit pancreatic lipase/colipase activity as thylakoids prepared by standard laboratory methods using sucrose in the medium and centrifugation. In a study with mice, it was found that, when the thylakoids were added to the food over 32 days, they significantly reduced the body weight gain and the percentage body fat. The large scale method described here allows studies on the effect of thylakoids in appetite regulation on experimental animals in a longer lasting time and also on humans.
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| 3. |
- Emek, Sinan Cem, et al.
(author)
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Pancreatic lipase-colipase binds strongly to the thylakoid membrane surface.
- 2013
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In: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 93:9, s. 2254-2258
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Journal article (peer-reviewed)abstract
- BACKGROUND: Isolated thylakoid membranes, i.e. the photosynthetic membranes of green leaves, inhibit the activity of pancreatic lipase and colipase during hydrolysis of fat in vitro. This inhibition has been demonstrated to cause reduced food intake and improved hormonal and lipid profile in vivo. One of the reasons suggested for the inhibiting effect is binding of lipase-colipase to the thylakoid membrane surface. This prompted a study of the binding of lipase and colipase to thylakoids. RESULTS: The results showed that lipase and colipase strongly bind to the thylakoid membrane surface. The dissociation constant was determined at 1.2 × 10(-8) mol L(-1) ; binding decreased after treatment of thylakoids with pepsin/trypsin to 1.0 × 10(-7) and to 0.6 × 10(-7) mol L(-1) after treatment with pancreatic juice. Similarly, delipidation of thylakoids caused a decrease in binding, the dissociation constant being 2.0 × 10(-7) mol L(-1) . CONCLUSION: The binding of pancreatic lipase-colipase to the thylakoid membrane is strong and may explain the inhibition of lipase-colipase activity by thylakoids. After treatment with proteases to mimic intestinal digestion binding is decreased, but is still high enough to explain the observed metabolic effects of thylakoids in vivo. © 2013 Society of Chemical Industry.
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| 4. |
- Emek, Sinan Cem, et al.
(author)
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Pigments protect the light harvesting proteins of chloroplast thylakoid membranes against digestion by gastrointestinal proteases
- 2011
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In: Food Hydrocolloids. - : Elsevier BV. - 0268-005X. ; 25:6, s. 1618-1626
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Journal article (peer-reviewed)abstract
- Chloroplast thylakoid membranes inhibit pancreatic lipase/colipase activity in vitro and, when included in food, induce satiety signals. As thylakoid membranes themselves are nutrients, containing lipids and proteins, it is of interest to study the digestion of thylakoids by enzymes of the gastrointestinal tract. Thylakoid membranes were treated with pepsin, trypsin, gastric and pancreatic juice at 37 degrees C and the resulting enzymatic breakdown was analyzed by gel electrophoresis, electron microscopy and mass spectroscopy. In all cases, several of the proteins were degraded within half an hour, while the main parts of the pigment-protein complexes were resistant for hours. Oil emulsified thylakoids were more resistant towards the enzymatic breakdown. Electron microscopy demonstrated that, after treatments, the thylakoids still remained in a membrane vesicular form. The capacity of thylakoid membranes to inhibit the lipase/colipase activity was partly reduced in all cases. About 50% of the inhibition capacity remained after treatment with pancreatic juice when the thylakoids were present in an oil emulsion. Delipidated thylakoids and plasma membranes, which lack the photosynthetic pigments, were degraded rapidly by pancreatic juice. Conclusion: The pigments, closely bound to the trans-membrane helices of thylakoid membrane proteins protect these from digestion by pepsin, trypsin, gastric and pancreatic juice. This supports the notion that a substantial inhibition of lipase/colipase takes place during the first 2 h in the intestine resulting in a retardation and prolongation of lipolysis in vivo. (C) 2010 Elsevier Ltd. All rights reserved.
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| 5. |
- Erlanson-Albertsson, Charlotte, et al.
(author)
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Inhibition of plant growth by the tetrapeptide des-arg enterostatin (VPDP).
- 1996
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In: Advances in Molecular and Cell Biology.
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Book chapter (other academic/artistic)abstract
- The effect of the tetrapeptide des-arg -enterostatin (Val-Pro-Asp-Pro) on the growth of muang bean, Vigna rodiate, was studied. At a concentration of 0.2mM in the nutrient solution the peptide reduced the growth significantly. Possible mechanisms underlying the growth inhibition are discussed.
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| 6. |
- Erlanson-Albertsson, Charlotte, et al.
(author)
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The Use of Green Leaf Membranes to Promote Appetite Control, Suppress Hedonic Hunger and Loose Body Weight.
- 2015
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In: Plant Foods for Human Nutrition. - : Springer Science and Business Media LLC. - 1573-9104 .- 0921-9668. ; 70:3, s. 281-290
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Journal article (peer-reviewed)abstract
- On-going research aims at answering the question, which satiety signal is the most potent or which combination of satiety signals is the most potent to stop eating. There is also an aim at finding certain food items or food additives that could be used to specifically reduce food intake therapeutically. Therapeutic attempts to normalize body weight and glycaemia with single agents alone have generally been disappointing. The success of bariatric surgery illustrates the rationale of using several hormones to treat obesity and type-2-diabetes. We have found that certain components from green leaves, the thylakoids, when given orally have a similar rationale in inducing the release of several gut hormones at the same time. In this way satiety is promoted and hunger suppressed, leading to loss of body weight and body fat. The mechanism is a reduced rate of intestinal lipid hydrolysis, allowing the lipolytic products to reach the distal intestine and release satiety hormones. The thylakoids also regulate glucose uptake in the intestine and influences microbiota composition in the intestine in a prebiotic direction. Using thylakoids is a novel strategy for treatment and prevention of obesity.
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| 7. |
- Erlanson-Albertsson, Charlotte, et al.
(author)
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Thylakoids Promote Satiety in Healthy Humans. Metabolic Effects and Mechanisms
- 2012
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In: ACS Symposium Series. - 0097-6156. ; 1093, s. 521-531
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Conference paper (peer-reviewed)abstract
- Thylakoids are the photosynthetic membranes of the chloroplasts in green leaves. Thylakoids have been found to promote satiety when added to food, both in animal experimental models and in human. The thylakoids act through inhibition of lipase-colipase catalysed hydrolysis of triacylglycerol, which is the main dietary fat component. The mechanism for inhibition is either a binding of thylakoids to lipase-colipase, which thereby prevents to act as a lipolytic enzyme complex or binding of thylakoids to the triacylglycerol droplet, thereby hindering the access of lipase-colipase to its substrate. Thylakoids consist of proteins and lipids in a membrane structure containing various protein-bound pigments. The thylakoid membranes are fairly resistant to gastrointestinal breakdown, which may be an important property to explain the satiety promoting effect. Satiety is promoted through the release of cholecystokinin, a gastrointestinal hormone that causes an inhibition of gastric emptying and stimulation of satiety mechanism in the brain. The hunger hormone ghrelin is suppressed as well as insulin. In human short-term experiments thylakoids added to food promote satiety signalling. In long-term a reduced body fat mass was observed.
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| 8. |
- Köhnke, Rickard, et al.
(author)
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Thylakoids promote release of the satiety hormone cholecystokinin while reducing insulin in healthy humans.
- 2009
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In: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 44:6, s. 712-719
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Journal article (peer-reviewed)abstract
- Objective. The effects of a promising new appetite suppressor named "thylakoids" (membrane proteins derived from spinach leaves) were examined in a single meal in man. Thylakoids inhibit the lipase/colipase hydrolysis of triacylglycerols in vitro and suppress food intake, decrease body-weight gain and raise the satiety hormone cholecystokinin (CCK) in rats, but their effects in man remain unclear. The aim of this study was to investigate whether thylakoids, when added to a test meal, affect appetite regulation and blood parameters in healthy individuals. Material and methods. In an intervention crossover study, healthy individuals of normal weight (n=11) were offered a high-fat meal with and without the addition of thylakoids. Blood samples were taken 0 (prior to meal), 30, 60, 120, 180, 240, 300 and 360 min after the start of the meal. Blood samples were analysed for satiety and hunger hormones (CCK, leptin and ghrelin), insulin and blood metabolites (glucose and free fatty acids). Results. The CCK level increased, in particular between the 120 min time-point and onwards, the ghrelin level was reduced at 120 min and leptin level increased at 360 min after intake of the thylakoid-enriched meal. The insulin level was reduced, whereas glucose concentrations were unchanged. Free fatty acids were reduced between time-point 120 min and onwards after the thylakoid meal. Conclusions. The addition of thylakoids to energy-dense food promotes satiety signals and reduces insulin response during a single meal in man.
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| 9. |
- Köhnke, Rickard, et al.
(author)
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Thylakoids suppress appetite by increasing cholecystokinin resulting in lower food intake and body weight in high-fat fed mice.
- 2009
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In: Phytotherapy Research. - : Wiley. - 1099-1573 .- 0951-418X. ; 23, s. 1778-1783
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Journal article (peer-reviewed)abstract
- Thylakoids are membranes isolated from plant chloroplasts which have previously been shown to inhibit pancreatic lipase/colipase catalysed hydrolysis of fat in vitro and induce short-term satiety in vivo. The purpose of the present study was to examine if dietary supplementation of thylakoids could affect food intake and body weight during long-term feeding in mice. Female apolipoprotein E-deficient mice were fed a high-fat diet containing 41% of fat by energy with and without thylakoids for 100 days. Mice fed the thylakoid-enriched diet had suppressed food intake, body weight gain and body fat compared with the high-fat fed control mice. Reduced serum glucose, serum triglyceride and serum free fatty acid levels were found in the thylakoid-treated animals. The satiety hormone cholecystokinin was elevated, suggesting this hormone mediates satiety. Leptin levels were reduced, reflecting a decreased fat mass. There was no sign of desensitization in the animals treated with thylakoids. The results suggest that thylakoids are useful to suppress appetite and body weight gain when supplemented to a high-fat food during long-term feeding. Copyright (c) 2009 John Wiley & Sons, Ltd.
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| 10. |
- Montelius, Caroline, et al.
(author)
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Chloroplast thylakoids reduce glucose uptake and decrease intestinal macromolecular permeability.
- 2011
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In: British Journal of Nutrition. - 1475-2662. ; 106:6, s. 836-844
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Journal article (peer-reviewed)abstract
- Thylakoid membranes, derived from chloroplasts, have previously been shown to retard fat digestion and lower blood glucose levels after oral intake. The purpose of the present study was to investigate the effect of thylakoid membranes on the passage of methyl-glucose, dextran and ovalbumin over rat intestine in vitro using Ussing chambers. The results show that thylakoids retard the passage of each of the test molecules in a dose-dependent way. The thylakoids appear to be attached on the mucosal surface and a mechanism is suggested that the thylakoids delay the passage of the test molecules by sterical hindrance. The present results indicate that thylakoid membranes may be useful both to control intestinal absorption of glucose and to enhance the barrier function of the intestine.
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