Furan fatty acids appear to be very potent scavengers of peroxyl
radicals. The benefits of eating a diet rich in fish may be in part
caused by the high content of furan fatty acids in fish compared to
other foods.
Ann N Y Acad Sci. 2008 Apr;1126:128-33.
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Click here to read
Peroxyl radicals are essential reagents in the oxidation steps of
the maillard reaction leading to generation of advanced glycation end
products.
Spiteller G.
Institute of Organic Chemistry, University of Bayreuth,
Universitätsstr. 30; D95440 Bayreuth, Germany. Gerhard.spiteller at (no spam) uni-
bayreuth.de.
Polyunsaturated fatty acids (PUFAs) are incorporated in all
membranes of mammalian and plant cells and are extremely sensitive to
oxygen. This property is used in nature to respond to any changes in
cell membrane structure. In the first step of a response, lipid
hydroperoxide molecules are generated. An increasing impact switches
the enzymatic reaction to a nonenzymatic one by generation of lipid
peroxyl radicals, which attack sugars by oxidation. In the course of
these reactions, hydrogen peroxyl radicals are generated, resembling
lipid peroxyl radicals in their reactivity. The reactions induced by
these radicals are not under genetic control, they attack nearly all
types of biological molecules (such as proteins, lipids, and sugars),
and are responsible for the deleterious cell alterations in aging and
age-related diseases (such as diabetes, Alzheimer's disease, or
atherosclerosis) and probably also in autoimmune diseases, which
involve sugars at the cell membranes. Lipid peroxidation processes are
induced by heating fats, meat, and other nutritional products. The
oxidation products generated by consumption of heated food cause
damage of mammalian cells. The deleterious reactions can be partly
reduced by consumption of plants and/or algae. These contain, among
other well-known antioxidants, furan fatty acids, which are important
scavengers of peroxyl radicals.
PMID: 18448806 [PubMed - in process]
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Here is a quote from the full text article:
"LPO is induced by frying meat or fats, for instance, by preparation
of chips in boiling oil that has been used for a long time. Although
the generated peroxyl radicals react instantly with other molecules
and are therefore not transferred to the body, the transformed
products are partly toxic, for instance cholesterol linoleate is
oxidized via peroxyl radicals to toxic oxidation products of
cholesterol.3 The toxic products are incorporated into our cells. LPO
products injure the cells and start new LPO processes that spread like
an infection from cell to cell,3 except that the radicals are
scavenged by antioxidants.
Many compounds, such as plasmalogens, are considered to be scavengers,
although only their disappearance was recognized in contact with
radicals. Radicals can not "disappear." If they react with a molecule
by hydrogen abstraction, they generate from the molecule a new radical
and the reaction is carried on. Therefore "disappearance" of a
compound after reaction with a radical does not qualify it to be a
radical scavenger. The chain reaction is only stopped if a radical has
a sufficiently long lifetime to be able to react with a second
radical.
Plants and algae are exposed to UV radiation, which induces generation
of LOO• radicals. Therefore, plants and algae produce long-living
radicals, such as vitamin E or flavonoids. Radicals produced from
these compounds have an extended mesomeric system that stabilizes the
radical and enhances their lifetime. Nevertheless, the consumption of
flavonoids seems to have little effect because flavonoids are not
adsorbed in the intestine and, therefore, are not incorporated into
our tissues. As a consequence, I doubt that drinking red wine, which
contains flavonoids, protects against radicals. Plants and especially
algae produce furan fatty acids. These not only are perfect radical
scavengers but also are incorporated, instead of PUFAs, in
phospholipids (Fig. 4).28"
Here are two more abstract on this subject by the same author:
Mol Biotechnol. 2007 Sep;37(1):5-12.
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The important role of lipid peroxidation processes in aging and
age dependent diseases.
Spiteller G.
Organic Chemical Department, University of Bayreuth,
Universitätsstrasse 30, Bayreuth, Germany. Gerhard.Spiteller at (no spam) uni-
bayreuth.de
Any change in the cell membrane structure activates lipoxygenases
(LOX). LOX transform polyunsaturated fatty acids (PUFAs) to
lipidhydroperoxide molecules (LOOHs). When cells are severely wounded,
this physiological process switches to a non-enzymatic lipid
peroxidation (LPO) process producing LOO* radicals. These oxidize
nearly all-biological molecules such as lipids, sugars, and proteins.
The LOO* induced degradations proceed by transfer of the radicals from
cell to cell like an infection. The chemical reactions induced by LO*
and LOO* radicals seem to be responsible for aging and induction of
age dependent diseases.Alternatively, LO* and LOO* radicals are
generated by frying of fats and involve cholesterol-PUFA esters and
thus induce atherogenesis.Plants and algae are exposed to LOO*
radicals generating radiation. In order to remove LOO* radicals,
plants and algae transform PUFAs to furan fatty acids, which are
incorporated after consumption of vegetables into mammalian tissues
where they act as excellent scavengers of LOO* and LO* radicals.
Publication Types:
* Research Support, Non-U.S. Gov't
* Review
PMID: 17914157 [PubMed - indexed for MEDLINE]
Related Articles
* The relation of lipid peroxidation processes with
atherogenesis: a new theory on atherogenesis. [Mol Nutr Food Res.
2005]
* Peroxyl radicals: inductors of neurodegenerative and other
inflammatory diseases. Their origin and how they transform
cholesterol, phospholipids, plasmalogens, polyunsaturated fatty acids,
sugars, and proteins into deleterious products. [Free Radic Biol Med.
2006]
* Are changes of the cell membrane structure causally involved
in the aging process? [Ann N Y Acad Sci. 2002]
* Lipid peroxidation in aging and age-dependent diseases. [Exp
Gerontol. 2001]
* Is atherosclerosis a multifactorial disease or is it induced
by a sequence of lipid peroxidation reactions? [Ann N Y Acad Sci.
2005]
* » See all Related Articles...
Lipids. 2005 Aug;40(
:755-71.
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Furan fatty acids: occurrence, synthesis, and reactions. Are furan
fatty acids responsible for the cardioprotective effects of a fish
diet?
Spiteller G.
Lehrstuhl für Organische Chemie I, University of Bayreuth,
Bayreuth, Germany. gerhard.spitel... at (no spam) uni-bayreuth.de
Furan FA (F-acids) are tri- or tetrasubstituted furan derivatives
characterized by either a propyl or pentyl side chain in one of the
alpha-positions; the other is substituted by a straight long-chain
saturated acid with a carboxylic group at its end. F-acids are
generated in large amounts in algae, but they are also produced by
plants and microorganisms. Fish and other marine organisms as well as
mammals consume F-acids in their food and incorporate them into
phospholipids and cholesterol esters. F-acids are catabolized to
dibasic urofuran acids, which are excreted in the urine. The
biogenetic precursor of the most abundant F-acid, F6, is linoleic
acid. Methyl groups in the beta-position are derived from
adenosylmethionine. Owing to the different alkyl substituents,
synthesis of F-acids requires multistep reactions. F-acids react
readily with peroxyl radicals to generate dioxoenes. The radical-
scavenging ability of F-acids may contribute to the protective
properties of fish and fish oil diets against mortality from heart
disease.
Publication Types:
* Research Support, Non-U.S. Gov't
* Review
PMID: 16296395 [PubMed - indexed for MEDLINE]
Related Articles
* The relation of lipid peroxidation processes with
atherogenesis: a new theory on atherogenesis. [Mol Nutr Food Res.
2005]
* The common occurrence of furan fatty acids in plants.
[Lipids. 1989]
* The occurrence of furan fatty acids in Isochrysis sp. and
Phaeodactylum tricornutum. [Biochim Biophys Acta. 1993]
* Catabolism of fish furan fatty acids to urofuran acids in
the rat. [Biochim Biophys Acta. 1983]
* Investigations of the origin of the furan fatty acids (F-
acids). [Lipids. 1988]
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Here is a quote from the full text article on the occurrence of furan
fatty acids in foods.
"F-acids were found in a great number of freshwater (28,29) and marine
fish (29-35) (see Table 2), and some minor compounds with variations
in the chain length have been detected (36). Morover, F-acids were
found as constituents of cod liver oil (29,36,37). F acids have been
detected in invertebrates (3
, such as crustaceans (crayfish)
(39-41), amphibians (bullfrog) (40), and reptiles (turtle) (40).
F-acids with unusual highly unsaturated chains in cc-positions were
isolated from marine sponges (42). F-acids were also found in marine
bacteria (43^5), algae (46,47), plants (48-50), yeast (49) and fungi
(49), food fats such as butter (51) and virgin olive oil (52),
mammalian tissue (53), and blood ineluding that of humans (54-56).
Thus, F-acids seem to be widely distributed in all living matter."
"Although F-acids occur in fish only in amounts of around 1% (29,36)
they might reduce the oxidation of LDL to a considerable extent
because they serve as potential radical scavengers (24) and inhibit
progression of nonenzymatic lipid peroxidation reactions (172). And
because radicals induce a chain reaction, the amount of F-acids may be
sufficient to suppress LDL oxidation."
Furan fatty acids appear to also be abundant in vegetables and fruits.
Lipids. 1989 Apr;24(4):296-8.
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The common occurrence of furan fatty acids in plants.
Hannemann K, Puchta V, Simon E, Ziegler H, Ziegler G, Spiteller G.
Lehrstuhl fur Organische Chemie I der Universitat Bayreuth,
Federal Republic of Germany.
The observation that F-acids (1) occur in rat chow initiated a
search for F-acids in human diet. We observed that the amount of F-
acids with a pentyl side chain in alpha-position taken up with a one-
day diet correlates well with the amount of excreted degradation
products, the pentyl urofuran acids (2), (3) and (4). Therefore it can
be concluded that F-acids with a pentyl side chain are not produced in
the human body but are introduced through the diet. The origin of F-
acids carrying an alpha-propyl side chain is less clear. The amount of
propyl-urofuran acids (2) and (3) excreted in urine was found in one
case out of three to be five times higher than the amount of F-acids
carrying a propyl group in alpha-position taken up by the diet.
Therefore, it can presently not be excluded that a portion of the
propyl F-acids is produced by the body. F-acids found in human food
are mainly introduced into the body by vegetables and fruits. F-acids
were found also in birch leaves in considerable amounts, as well as in
grasses, dandelion and clover leaves. Thus, we can conclude that F-
acids are common constituents of plants.
Publication Types:
* Research Support, Non-U.S. Gov't
PMID: 2755307 [PubMed - indexed for MEDLINE]
Related Articles
* The occurrence of furan fatty acids in Isochrysis sp. and
Phaeodactylum tricornutum. [Biochim Biophys Acta. 1993]
* Furan fatty acids: occurrence, synthesis, and reactions. Are
furan fatty acids responsible for the cardioprotective effects of a
fish diet? [Lipids. 2005]
* Investigations of the origin of the furan fatty acids (F-
acids). [Lipids. 1988]
* Furanoid fatty acids from fish lipids. [Lipids. 1975]
* Catabolism of fish furan fatty acids to urofuran acids in
the rat. [Biochim Biophys Acta. 1983]
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