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Metabolites of Avena sativa with Blood Cholesterol Lowering Properties

Thuresson, Narda LU (2017)
Abstract (Swedish)
Popular Science Summary

Oat is one of the cereals that has been increasing in popularity during the last years. Oats are usually consumed for breakfast as a porridge, muesli, bread, or oat drinks which are included in, for example, smoothies. But why is it important to consume oats?

There are two types of cholesterol, bad cholesterol and good cholesterol. The bad cholesterol can build up plaque inside arteries, and thus increase the risk of dangerous illness. On the other hand, good cholesterol helps to remove the plaque from the arteries.

Consumption of oats in humans and animals has been shown to reduce bad cholesterol and thus reducing the risk of, for example, atherosclerosis. The reason why oats are good for... (More)
Popular Science Summary

Oat is one of the cereals that has been increasing in popularity during the last years. Oats are usually consumed for breakfast as a porridge, muesli, bread, or oat drinks which are included in, for example, smoothies. But why is it important to consume oats?

There are two types of cholesterol, bad cholesterol and good cholesterol. The bad cholesterol can build up plaque inside arteries, and thus increase the risk of dangerous illness. On the other hand, good cholesterol helps to remove the plaque from the arteries.

Consumption of oats in humans and animals has been shown to reduce bad cholesterol and thus reducing the risk of, for example, atherosclerosis. The reason why oats are good for reducing the bad cholesterol is due to the presence of big molecules such as soluble fibers in oats. Furthermore, we suggest that small molecules in oats also have the ability to reduce bad cholesterol.

In our everyday life, we use different types of oils, such olive oil or sunflower oil. Oat oil is chemically similar to other oils, but has a particular golden color. However, it is not very common to find it in the market. In our studies, we developed a method in which we could demonstrate that small molecules present in oat oil can reduce bad cholesterol in the body. (Less)
Abstract
Cardiovascular diseases are among the most important causes of death in the
developed countries. These diseases are partly caused by too high cholesterol
concentrations in the blood. Avena sativa, oat, is the most common spieces of the genus Avena, and produced in huge amounts worldwide. Oats have been shown to have cholesterol-lowering properties since the 1960s. This property was originally attributed to the ß-glucans, however, it has also been observed that other compounds, which are soluble in organic solvents (not ß-glucans), are able to lower the cholesterol concentration in the blood in rats as well as in humans.

The aim of this thesis has been to obtain a better understanding about the
relationship between the... (More)
Cardiovascular diseases are among the most important causes of death in the
developed countries. These diseases are partly caused by too high cholesterol
concentrations in the blood. Avena sativa, oat, is the most common spieces of the genus Avena, and produced in huge amounts worldwide. Oats have been shown to have cholesterol-lowering properties since the 1960s. This property was originally attributed to the ß-glucans, however, it has also been observed that other compounds, which are soluble in organic solvents (not ß-glucans), are able to lower the cholesterol concentration in the blood in rats as well as in humans.

The aim of this thesis has been to obtain a better understanding about the
relationship between the cholesterol lowering effect (CLE) and compounds
naturally present in oats (besides ß-glucans).

Initially, avenanthramides (AVAs), which is a major group of phenolic compounds present in oats, were detected and quantified in order to search for any relationship between the contents of AVAs in oats and a CLE. However, there
was no obvious relationship, and it seems unlikely that the AVAs contribute
significantly to the CLE. During this study, it was necessary to prepare AVAs by
synthesis, as their isolation from oats as pure compounds in larger amounts is
rather complicated. Fourteen AVAs, whereof six are natural products, were
synthesized, and used as standards for the analytical work as well as for in vitro
assays. The three most prevalent AVAs in oat, avenanthramides (1), (2), and (3)
were evaluated in vitro for their ability to prevent oxLDL-induced lipid
accumulation in murine macrophages. However, the pre-incubation of
the macrophages with the three AVAs (1), (2), and (3) did not alter the mRNAexpression of scavenger receptors or lipid transporters of the macrophages.

Bio-assay guided fractionation was used to find the fraction of oat with the
strongest CLE. Oat extracts were fractionated and the fractions were tested in vivo. The fraction rich in phytosterols showed the best CLE. However, another
compound, 13-HODE, was also present in the fractions showing CLE. Thus, it
was not possible to link the CLE to a specific compound or compounds. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Horsfelt Skibsted, Leif, University of Copenhagen, Denmark
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Cholesterol lowering effect, Avena sativa, phytosterols, avenanthramides, 13-HODE
pages
144 pages
publisher
Lund University, Faculty of Science, Department of Chemistry, Centre for Analysis and Synthesis
defense location
Lecture hall B, Center for chemistry and chemical engineering, Naturvetarvägen 14, Lund.
defense date
2017-11-10 10:00
ISBN
978-91-7422-549-1
978-91-7422-549-5
language
English
LU publication?
yes
id
d63e5bd6-2eed-4cf8-b5ac-8b63a201486e
date added to LUP
2017-10-16 11:20:26
date last changed
2017-10-25 14:56:46
@phdthesis{d63e5bd6-2eed-4cf8-b5ac-8b63a201486e,
  abstract     = {Cardiovascular diseases are among the most important causes of death in the<br/>developed countries. These diseases are partly caused by too high cholesterol<br/>concentrations in the blood. Avena sativa, oat, is the most common spieces of the genus Avena, and produced in huge amounts worldwide. Oats have been shown to have cholesterol-lowering properties since the 1960s. This property was originally attributed to the ß-glucans, however, it has also been observed that other compounds, which are soluble in organic solvents (not ß-glucans), are able to lower the cholesterol concentration in the blood in rats as well as in humans.<br/><br/>The aim of this thesis has been to obtain a better understanding about the<br/>relationship between the cholesterol lowering effect (CLE) and compounds<br/>naturally present in oats (besides ß-glucans).<br/><br/>Initially, avenanthramides (AVAs), which is a major group of phenolic compounds present in oats, were detected and quantified in order to search for any relationship between the contents of AVAs in oats and a CLE. However, there <br/>was no obvious relationship, and it seems unlikely that the AVAs contribute<br/>significantly to the CLE. During this study, it was necessary to prepare AVAs by<br/>synthesis, as their isolation from oats as pure compounds in larger amounts is<br/>rather complicated. Fourteen AVAs, whereof six are natural products, were<br/>synthesized, and used as standards for the analytical work as well as for in vitro<br/>assays. The three most prevalent AVAs in oat, avenanthramides (1), (2), and (3)<br/>were evaluated in vitro for their ability to prevent oxLDL-induced lipid<br/>accumulation in murine macrophages. However, the pre-incubation of <br/>the macrophages with the three AVAs (1), (2), and (3) did not alter the mRNAexpression of scavenger receptors or lipid transporters of the macrophages.<br/><br/>Bio-assay guided fractionation was used to find the fraction of oat with the<br/>strongest CLE. Oat extracts were fractionated and the fractions were tested in vivo. The fraction rich in phytosterols showed the best CLE. However, another<br/>compound, 13-HODE, was also present in the fractions showing CLE. Thus, it<br/>was not possible to link the CLE to a specific compound or compounds.},
  author       = {Thuresson, Narda},
  isbn         = {978-91-7422-549-1},
  keyword      = {Cholesterol lowering effect,Avena sativa,phytosterols,avenanthramides,13-HODE},
  language     = {eng},
  pages        = {144},
  publisher    = {Lund University, Faculty of Science, Department of Chemistry, Centre for Analysis and Synthesis},
  school       = {Lund University},
  title        = {Metabolites of Avena sativa with Blood Cholesterol Lowering Properties},
  year         = {2017},
}