Journal of Cell and Molecular Biology 5: 71-79, 2006.
Haliç University, Printed in Turkey.
Sterols and the phytosterol content in oilseed rape (Brassica napus L.)
Muhammet Kemal Gül *1 and Samija Amar 2
1 Çanakkale Onsekiz Mart University Department of Field Crops, 17020 Çanakkale, Turkey
2 Goettingen Georg-August University Department für Nutzpflanzenwisschenschaften, A b t e i l u n g
Pflanzenzüchtung Von-Siebold Str. 8 37075 Goettingen/, Germany (*author for correspondence)
Received 23 February 2006; Accepted 12 July 2006
Sterols are natural, organic compounds with a molecular nucleus of 17 carbon atoms and a characteristic threedimensional
arrangement of four rings. From the chemical point of view sterols are steroid alcohols and their name
is derived from Greek stereos, which mean solid with ending –ol, which is the suffix for alcohols. As essential
constituents of cell membranes, they are widely distributed in all eukaryotic organisms. Playing a structural role in
cellular membranes, they present a significant part of the organism membrane biomass, while their functional role is
evident through the participation in the control of membrane-associated metabolic processes, such as: regulations of
membrane permeability and fluidity, signal transduction events and the activity of membrane-bound enzymes.
Sterols are the precursors of steroid hormones and bile acids in humans, brassinosteroids - phytohormones in plants
and, as the recent identifications of sterol mutants have shown, they are involved in important growth and
developmental processes in living organisms. In recent years increased interest in phytosterols lies in their potential
to reduce plasma low-density lipoprotein cholesterol level, decreasing coronary mortality and therefore acting as
naturally preventive dietary product. In the last decades, more than 40 different sterols were well identified in
different cultivars. These sterols are called phytosterols and they are predominantly present in oilseed plants. The
phytosterol content range between 1.41-15.57 gr/ kg oil and this depends to plant species. Oilseed rape is one of the
most important oil seed crop in the world. phytosterol content in new oilseed rape varieties rang between 5.13 and
9.79 gr/kg oil.
Key Words: Sterol, phytosterol oilseed rape, plant, human
Kolza bitkisinde (Brassica napus L.) sterol ve fitosterol içeri¤i
Steroller organik bileflikler olup 17 karbon atomundan ve 3 boyutlu dört halka dizisinden oluflmufllard›r. Kimyasal
aç›da bak›ld›¤›nda steroller steroid alkolü olup, sterol ad› Yunanca’da stereos, dayan›kl› yada bozulmayan anlam›na
gelmektedir. Sterolün sonuna eklenen –ol tak›s› ise alkolden gelmektedir. Hücre membranlar›n›n özel yap›s›ndan
dolay› steroller tüm okaryotik canlilarda bulunurlar. Hücre membran›nda yap›sal bir rol oynad›klar›ndan steroller
organizmalar›n membranlar›n›n önemli bir k›sm›n› teflkil ederken, hücre membran› geçirgenli¤inde önemli görevler
alarak bu sistem içinde görev alan enzimlerin aktif hale getirmektirler. Son olarak sterollerin insanlarda öncü steroid
hormanlar› ile safra asitlerini, bitkilerde brassinosteroidler ile fitohormonlar› etkiledi¤ini, son yap›lan çal›flmalarda
da sterollerin canl› organizmalar›n önemli büyüme ve geliflme evrelerinde rol ald›klar› saptanm›flt›r. Son y›llarda
fitosterollerin LDL kolesterol düzenleyicisi özellikleri, kroner ölümleri azalt›c› etkileri bak›m›ndan do¤al önleme
ürünü olmalar› sebebiyle önemleri artm›flt›r. Bitkilerde çok iyi tespit edilip belirlenen 40’dan fazla farkl› sterol
bulunmufltur. Bu steroller ço¤unlukla ya¤ bitkilerinde saptanarak fitosterol olarak adland›r›lm›fllard›r. Yap›lan
çal›flmalarda kültür bitkisine göre elde edilen 1 kg ya¤da bulunabilecek fitosterol iktar› 1,41-15,57 gr/kg arala¤›nda
oldu¤u saptanm›flt›r. Kolza dünyada üretilen en önemli ya¤ bitkilerinden biridir. Kolzada fitosteroller miktar› 5,13 ile
9,79 gr/kg ya¤ aras›nda de¤iflim göstermektedir.
Anahtar Sözcükler: Sterol, fitosterol, kolza, bitki, insan
72 M. Kemal Gül and Samija Amar
Sterols are natural, organic compounds and they are
widely distributed in all eukaryotic organisms. They
present a significant part of the organism membrane
biomass, while their functional role is evident through
the participation in the control of membraneassociated
metabolic processes, such as: regulations of
membrane permeability and fluidity, signal
transduction events and the activity of membranebound
enzymes (Piironen et al., 2000). Sterols are the
precursors of steroid hormones and bile acids in
humans, brassinosteroids - phytohormones in plants
and, as the recent identifications of sterol mutants have
shown (Lindsey et al., 2003), they are involved in
important growth and developmental processes in
living organisms (Hartmann, 1998). Plants have a
variety of more than 40 well-identified and studied
sterols (Law, 2000), which are termed phytosterols and
are predominantly present in oilseed plants. Cereals
are recognised as a significant source of phytosterols
as well, whereas phytosterol content in vegetables and
nuts is considerably lower (Piironen et al., 2000;
Piironen et al., 2003; Normen et al., 1999). The most
abundant phytosterols are: sitosterol, campesterol and
stigmasterol. Other phytosterols like avenasterol and
cycloartenol are synthesised earlier in the biosynthetic
pathway and as sterol precursors they usually occur in
relatively smaller amounts (Määttä et al., 1999).
Phytosterols are, with respect to their physiological
function and their chemical structure, similar to the
major and only animal produced sterol – cholesterol.
Increased scientific interest and economic
importance, in the past few decades, in the most
important oil crop in Europe – rapeseed, has been
largely due to its improved quality of oil seeds, which
can yield between 40 and 47 percentages of oil
(Becker et al., 1999). Brassica napus L., known as
rapeseed, rape, or in some cultivars, low in erucic acid
and glucosinolate content, as canola, belongs to the
genus B r a s s i c a , which is a member of the
Brassicaceae (Cruciferae) f a m i l y. This family, of
about 375 genera and 3200 species, includes crops,
condiments and ornamentals but only genus Brassica
is well known for their admirable phenotypical
diversity: cabbage, cauliflower, broccoli, Brussels
sprouts, kohl-rabi, turnip, black and white mustards,
garden cress and so forth (Gomez-Campo, 1999). Like
other vegetable oils, the rapeseed oil is the richest
natural source of phytosterols. Apart from phytosterols
rapeseed oil is predominantly composed of fatty acids,
such as oleic acid, linoleic and linolenic acid (vitamin
F complex), of phospho- and glycolipids and of
tocopherols (vitamin E) and carotenoids - pro-vitamin
A (Rehm and Espig, 1991). Therefore, it became
reasonable to increase the rapeseed oil production.
According to “Food Outlook” (FAO, 2004) from Food
and Agriculture Organisation of the United Nations,
global production of rapeseed crop rose more than
10 % from 1998 to 2002, with the estimation for 2004
that it will reach second place after soybean.
Encouraged with the development of improved rape
cultivars with high quality edible oils and most recent
utilisation of rapeseed oil for bio-diesel (biogenic fuel)
production (UFOP, 2004), the EU farmers expanded
rapeseed planting, exceeding those of soybean,
sunflower, groundnut and cottonseed (Kimber and
Phytosterols have been isolated from a large number
of species and according to numerous publications
(Grunwald, 1980; Gordon and Miller, 1997; Dutta and
Normen, 1998; Piironen et al., 2000) they probably
exist in all angiosperm and gymnosperm species.
Although, there are more than 40 diff e r e n t
phytosterols found in higher plants, sitosterol,
campesterol and stigmasterol often predominate,
while other phytosterols are usually typical only for
certain plant family or even species. Brassicasterol is
for example typical only for Brassicaceae family, and
therefore it could be used for identification
Chemical structure and properties
Sterols belong to a large group of hydrocarbons,
o rganic chemical compounds known as
polyisoprenoids with carbon skeletons structurally
based and derived from multiple isoprene, five carbon
unit -CH 2=C(CH 3)CH=CH 2. Sterols are, together with
tocopherols, carotenoids and chlorophylls, formed by
polymerisation of isoprene unit (Grunwald, 1980).
The structural feature, which virtually all sterols
have in common, is that they are derivatives of a
tetracyclic perhydro-cyclopentano-phenanthrene ring
system with a flexible side chain at the C-17 atom
(Figure 1) and 3β-monohydroxy compounds and
Animal cells contain only one major sterol, i.e.
c h o l e s t e ro l (Figure 2a). Cholesterol also occurs,
though only in a few percentage of the whole sterol
content, in plants (Gordon and Miller, 1997).
Chemically, it is an analogue to the phytosterols,
differing only in the side chain. Fungal cells, together
with some unicellular algae and lichens synthesise
ergosterol - provitamin D2 (Grunwald, 1980; Rehm
and Espig, 1991). Namely, ergocalciferol (vitamin D2)
is produced by ultraviolet irradiation of provitamin D2
( e rgosterol), which occurs in yeast and fungi (Figure 2b).
In contrast to animal cells and fungi, plant cells
synthesize complex array of phytosterol mixtures with
the sterol profiles varying between species.
The scientific names of phytosterols are given to
them according to the number of C atoms in the C-17
side chain, the number and the position of the double
Sterols and phytosterols in oilseed rape 73
Figure 1. Chemical structure of 5 α cholestan 3β-ol (adapted from Piironen et al., 2000)
bond in the ring system and the side chain. Their
scientific names are usually very complex, so the most
common phytosterols are referred to by their trivial
names. The trivial and the scientific names of the most
important phytosterols are given in Table 1.
According to the IUPAC recommendations from
1989, sterol molecules consist of four rings marked as
A, B, C and D with standard carbon numbering
(Figure 1). Three rings, A, B and C, have 6 carbons
atom nonlinear structure and they are fused to one 5
carbons atom ring (D). The various phytosterols found
in plants differ in number of C atom in the side chain
at the C-17 atom and the position and the number of
the double bonds in the ring system. T h e
predominating phytosterols in plants are: campesterol
sometimes referred to as 24-methylcholesterol (Figure
3a), sitosterol (Figure 3c) and stigmasterol (Figure 3d).
Figure 2. Chemical structure of a. cholesterol and b. ergosterol (taken from Kyoto Encyclopedia of Genes and Genomes, 2004)
74 M. Kemal Gül and Samija Amar
The phytosterol composition of family Brassicaceae
to which rapeseed belongs, differ from most plant
species for an additional brassicasterol (Figure 3e)
while avenasterol (Figure 3b) is considered as one of
the main phytosterol in cereals but, as it has been
discussed (Dutta and Normen, 1998; Piironen et al.,
2002), avenasterol also occurs in Brassica napus seed.
In addition to their vast structural variations,
arising from different substitution in the side chain and
number and the position of double bonds in the
tetracyclic skeleton, different phytosterols play
various roles in higher plants. Yet, it still remains
unknown why do plants require a mixture of
phytosterols instead of only one like animals and fungi
and does each phytosterol play a specific function in
plant metabolism? Further on, for the phytosterol
classification, it is important whether the different side
chains, or functional groups of rings system, are in α,
i.e. under the plain of the cyclic system, or above the
plain - in a β position (IUPAC, 1989). For example,
the side chain and the two methyl groups at C-18 and
C-19 are angular to the ring structure and above the
plane, thus having β-stereochemistry, with additional
3-hydroxyl group also having β- s t e r e o c h e m i s t r y
(Figure 1). Another characteristic specific only to
phytosterols is the alkylation of a C atom at 24 th
position (Figure 3). Sitosterol and stigmasterol have
an ethyl group at C-24 in α-position, whereas
campesterol a methyl group at α- and brassicasterol a
methyl group at β-position (Table 1). According to
their structural and biosynthetical basis, phytosterols
can be divided into three groups: 4-desmethyl, 4monomethyl
and 4,4-dimethyl phytosterols (Table. 1).
Most abundant are three 4-desmethyl sterols:
sitosterol, campesterol and stigmasterol. Other
phytosterols like 4-mono- and 4,4-dimethyl sterols are
synthesised earlier in biosynthetic pathway, so they are
mainly sterol precursors and usually occur in
relatively smaller amounts (Määttä et al., 1999). The
last two are mostly precursors of the sterol
biosynthetical pathway and exist in lower level. The 4desmethyl
sterols can also be distinguished according
to their saturation and position of double bond on the
C-5 and C-7 atoms in the B ring (Figure 1). The
unsaturated sterols are marked with Δ 5 and Δ 7 ,
r e s p e c t i v e l y. Most phytosterols (e.g. stigmasterol,
sitosterol, campesterol, brassicasterol and avenasterol)
belong to the group of Δ 5 unsaturated phytosterols.
Phytosterols with ethyl group at the 24 th C-atom - 24-
ethylsterols (sitosterol, stigmasterol and avenasterol),
mainly have only one type of configuration: 24α.
According to Salo et al. (2003) and Hartmann (1998),
24-methylsterols can consist of a mixture of two
epimers. That is to say, 24-methylsterol is a mixture of
2 4α-methylsterol and 24β-methylsterol know as
campesterol or 22,23 dihydrobrassicasterol (Figure 3a).
Phytosterols are largely hydrophobic having one
polar - hydroxyl group at 3 rd C-atom, making them
amphiphilic. According to one of the sterol
classifications phytosterols with free 3β- hydroxyl
group, are named free phytosterols (Figure 3) and they
are the major end product of biosynthetic pathway of
phytosterols. However, phytosterols also occur as
steryl esters where 3β-hydroxyl group of free
phytosterols is esterified with a long chain of saturated
or unsaturated fatty acids (Figure 4a), mainly linoleic
and oleic, or with phenolic acids (Figure 4d). Steryl
glycosides are formed when the 3β-hydroxyl group is
linked with monosaccharides, usually glucose, at the
first C position (Figure 4c).
When this monosaccharide is at the 6-C position
esterified with fatty acid, than so-called acylated steryl
glycosides are formed (Figure 4b).
Biological functions in plants
Phytosterols have both structural and metabolic
functions. Structural role is obvious through the fact
that they are integral membrane components. Being
incorporated into membranes they are determining the
characteristics of plasma membrane and, additionally,
of endoplasmic reticulum and mitochondria
membranes. Most likely, they also have a certain
function in the membrane adaptation to temperature
variations (Piironen et al., 2000). Participating in the
control of metabolic processes, such as regulation of
membrane permeability, fluidity, signal transduction
events for cell division and even activity of
membrane-bound enzymes, they fulfil their metabolic
role (Hartmann, 1998; Lindsay et al., 2003).
Interacting with their side chain, with the fatty acyl
moiety of membrane phospholipids and proteins
complexes, phytosterols restrict the motion of
membrane bilayers (i.e. the sterol ordering effect),
regulating membrane fluidity (Nes, 1987).
It has been postulated that sitosterol and
campesterol are most efficient in membrane
permeability and fluidity regulation and there are
evidence that stigmasterol play an important role in
cell proliferation, but has reduced ordering effect
(Hartmann, 1998). Finally, it appears that they
influence the plant development through the
localisation and functionality of key regulatory
proteins (Lindsey et al., 2003). During the seed
germination, the phytosterol content increases, which
is due to intensive membrane biosynthesis.
Phytosterols that are accumulated in seeds and
meristematic tissue are playing an important role in
cellular proliferation and differentiation. Furthermore,
in youngest plant tissues, the membrane biosynthesis
is more intensive. Consequently, phytosterol synthesis
will appear mostly during the seed formation and
germination and phytosterols themselves will provide
a supply for the growth of new cells and young shoots.
By the time when seeds are already mature or tissues
ages, the intensity of biosynthesis will decline
(Grunwald, 1980). Besides, the high phytosterol
amount could be also largely explained by the
anatomical structure of different plant tissues. For
instance, flower heads of broccoli and cauliflower
(Brassica oleracea L. ) have higher proportion of
membrane-rich meristematic tissue, which results in
Sterols and phytosterols in oilseed rape 75
Figure 3. Examples of the most important phytosterols showing the difference in their chemical structure: a. campesterol,
b. avenasterol, c. sitosterol, d. stigmasterol and e. brassicasterol (taken from Kyoto Encyclopedia of Genes and Genomes, 2004)
higher content of total phytosterols in this species in
comparison with other vegetables, fruits or berries
(Piironen et al., 2003; Normen et al., 1999).
M o r e o v e r, free phytosterols are precursors of
bioactive steroids, growth factors and substrates for
synthesis of numerous secondary plant metabolites
(Willmann, 2000; Piironen et al., 2003). Campesterol
is the precursor of brassinosteroids - phytohormones
found in Brassica pollen (Benveniste, 2002). Plant
steryl esters, intracellularly distributed, represent a
storage form of phytosterols, analogously as
cholesterol esters in mammalian cells (Piironen et al.,
Biological functions of phytosterols in humans
In contrast to phytosterols, cholesterol can be in
humans, either synthesised de novo in liver, or taken
up from the environment. During the process of
cholesterol absorption, it is being transported from the
lumen of intestine, across the intestinal wall and into
the blood. Low-density lipoprotein (LDL) then
transports cholesterol through the blood system.
Narrowing the channels of the blood vessels, LDL-
76 M. Kemal Gül and Samija Amar
Figure 4. Examples of steryl conjugated structures: a. oleic acid steryl ester, b. palmitic acid steryl glycosides, c. steryl glycosides
and d. phenolic acid steryl ester (adapted from Piironen et al., 2000)
cholesterol thus constricts the blood flow and those
people with high cholesterol levels eventually become
more susceptible to Cardiovascular Diseases (CVD)
such as: coronary heart disease (CHD), also known as
heart attack, hypertension (high blood pressure),
cerebrovascular (stroke) and peripheral vascular
diseases (Salo et al., 2003). According to the “World
Health Report 2003” of United Nations World Health
Organisation, heart attacks and strokes kill 12 million
people around the world every year, from which,
around 75% of CVD can be attributed to the major
risks: high cholesterol, high blood pressure and low
fruit and vegetable intake. By 2010 estimations are
that CVD will be the leading cause of death in
developing countries. Since the medical care of CVD
is costly and prolonged, there is, consequently, an
evident need for cholesterol suppression.
According to many conducted experiments
phytosterols decreases serum total and LDL
cholesterol levels (Gylling et al., 1997; Miettinen,
2001; Nissinen et al., 2002; Trautwein et al., 2003). It
was suggested that phytosterols compete at the same
time, in the micellar phase of the small intestine, for
the limited space with cholesterol. Micelles are the
essentially small aggregates, which are carrying a
mixture of lipids and bile salts in intestinal lumen.
Sitostanol esters, 5α-saturated sitosterol esters, were
recognised as the most efficient for reducing the serum
cholesterol concentration and the intestinal cholesterol
absorption (Nissinen et al., 2002). As it seems they
could be easily produced by sterol hydrogenation and
trans-esterification with polyunsaturated fatty acids
(Piironen et al., 2000). Sitostanol esters apparently
result similar in prevention of cholesterol absorption
but, in contrast to phytosterol esters, they do not
increase their own absorption. In addition to this fact,
it has been confirmed (Miettinen, 2001) that relatively
high campesterol content, in some phytosterol
complexes like soy phytosterols for example, can
increase the campesterol proportion in serum, what
w a s n ’t acknowledged for plant stanols, including
campestanol (5α-saturated campesterol). Phytosterol-
ich diets may thus, result in symptoms analogue to
phytosterolemia, hereditary metabolic disorder
characterised by elevated phytosterol level in blood
and tissue. Additional esterification of phytosterols
and stanols with long chain of mono- or
polyunsaturated fatty acids will increase their lipid
solubility, facilitating their incorporation into the food,
at the same time.
A new rapeseed margarine Benecol, obtained from
rapeseed oil by phytostanols trans-esterification
(Miettinen, 2001) and enriched with sitostanol-esters
was first launched in ’95 in Finland (Miettinen et al.,
1995) and by the end of ’99 already introduced in
several other European countries and worldwide (Law,
2000). Functional spreadable oils and fats, with
corresponding products like: margarine, milk and
yoghurt, first appeared in Germany in July 2002,
under the product name “Becel pro-activ”. It was
found that 3 g/day of phytostanol ester margarine, like
Benecol, could actually reduce the LDL cholesterol
level up to 14-22 %, decreasing the amount of
Sterols and phytosterols in oilseed rape 77
Table 1. Trivial and scientific names of selected sterols from the sterol biosynthetic pathway (adapted from Grunwald, 1980)
Trivial Name Scientific Name Sterol Class
Cycloartenol 9beta,19-cyclo-24-lanosten-3beta-ol 4,4-dimethyl
24-Methylene Lophenol 4-alpha-Methyl-5-alpha-ergosta-7,24-dien-3-beta-ol 4-methyl
Avenasterol 24-ethylcholesta-5,24(28)Z-dien-3‚-ol 4-desmethyl
Cholesterol cholest-5-en-3‚-ol 4-desmethyl
Campesterol 24·-methyl-5-cholestern-3‚-ol 4-desmethyl
Brassicasterol 5,22-cholestadien-24‚-methyl-3‚-ol 4-desmethyl
Sitosterol 24·-ethylcholest-5-en-3‚-ol 4-desmethyl
Stigmasterol 5,22-cholestadien-24·-ethyl-3‚-ol 4-desmethyl
Table 2. Variation of phytosterol content in six different vegetable oils (g/kg of oil) (adapted from Piironen et al., 2000)
Oil Type Brassicasterol Campesterol Stigmasterol Sitosterol Avenasterol Total Phytosterols
Corn * 2.59 0.98 9.89 0.36 8.09-15.57
Rapeseed 0.55-0.73 1.59-2.48 0.02-0.04 2.84-3.59 0.13-0.19 5.13-9.79
Sunflower - 0.69 0.75 4.65 0.28 3.74-7.25
Cottonseed * 0.26 * 4.00 0.05 4.31-5.39
Soybean - 0.62-0.76 0.45-076 1.22-2.31 - 2.29-4.59
Olive (Extra Virgin) - 0.05 0.01 1.18-1.21 0.17-0.18 1.41-1.50
*found in traces
absorbed cholesterol up to 65 % (Law 2000; Miettinen
et al., 1995; Miettinen, 2001; Jones et al., 1999). The
reduction of LDL cholesterol level up to 20 % was,
according to Gylling et al. (1997), achieved with the
rapeseed margarine (5 %) and with the sitostanol
esters (15 %) present in that margarine. In this study, it
has been also proven that consumption of roughly 2 g
a day of phytosterol-enriched margarines can decrease
the coronary mortality, by about 25 %. Furthermore,
latest experimental studies have shown that dietary
phytosterols may be used also as prevention for
several types of cancer e.g. stomach and colon cancer
(Normen et al., 2001).
Genetic variation and modification
Gordon and Miller (1997) have published results of a
steryl ester composition in 10 different oil types: corn,
rapeseed, groundnut, olive, soybean, safflower, oleic
sunflower, linoleic sunflower, cottonseed and palm oil.
They have discovered that rapeseed had, after the corn
78 M. Kemal Gül and Samija Amar
oil, second highest phytosterol proportion in oil. The
mean content in oil of five rapeseed varieties was 6900
mg/kg, in which the free phytosterol fraction equals
65 % and the steryl ester fraction equals 35 %, of the
total phytosterol content. They have published that
their phytosterol content in oil can vary to a great
extent from 6540 mg/kg to 8550 mg/kg of oil.
Nevertheless, the average total sterol content of
6900mg/kg classifies rapeseed oil, into oils with the
highest content i.e. higher than 4000 mg/kg of oil. On
the other hand Appelqvist et al. (1981) ascertained the
content of free phytosterols in the total amount of
rapeseed oil would be then 0.3 % and esterified
phytosterols 0.6 %. Piironen et al. (2000) have
published collected results of phytosterol content in
crude corn, cottonseed, rapeseed, olive, soybean and
sunflower oil (Table. 2), in which they have showed
the majority of crude vegetable oils contain, at least
1 g/kg to 5 g/kg of oil. However, they have found that
the most significant exceptions are corn (up to 16 g/kg
of oil) and rapeseed oil (up to 10 g/kg of oil).
According to Abidi et al. (1999) the total
phytosterol content is affected by genetic
modifications. They have compared 10 experimental
transgenic and non-transgenic canola genotypes
differing in fatty acid composition and concluded that
the phytosterol content was influenced by the genetic
modification of the fatty acid composition. A
significant decrease in amount of three major
phytosterols: sitosterol, campesterol and
brassicasterol, was observed in non-transgenic canola
varieties grown for low-linolenic and high oleic acid.
In addition, the amount of brassicasterol varied widely
based on genotype and growing conditions.
Brassicasterol content ranged from 85 to 189 mg/100 g
of modified oil; campesterol content ranged from 205
to 264 mg/100 g; sitosterol from 457 to 509 mg/100 g
and finally variation of the total phytosterol contents
was from 766 to 961 mg/100 g of modified oil. On the
other hand, there wasn’t any systematic trend of
phytosterol content in transgenic canola lines. In his
paper Miettinen (2001) discussed on what plant
breeders should focus when trying to developing new
nutritionally interesting plant with an ideal phytosterol
content, which could be later on used for cholesterollowering
functional food production. He suggested
that ideal phytosterol composition should contain
mainly sitosterol esters with low campesterol ester
content, because apparently campesterol esters result
in similar changes, when reduction of serum
cholesterol level is concerned, but at the same time, in
contrast to sitosterol esters, they increase their own
absorption. His second suggestion for oil, which
would be preferable for preparation of functional food,
was that it should be rich with stanols, especially
sitostanol, esterified with polyunsaturated fatty acids.
Since phytostanols are less abundant in plants than
phytosterols, in order to produce esterified
phytostanols, the final food price will increase.
Plant sterols, also called phytosterols, occur as organic
compounds and essential constituents of cell
membranes in all plant oils. Recently increased
interest in phytosterols lies in their potential to reduce
plasma low-density lipoprotein cholesterol level,
decreasing coronary mortality and therefore acting as
naturally preventive dietary product. High
expectations have already been put forward regarding
phytosterol analysis and traditional plant-breeding
applications in developing improved cultivars with
desirable phytosterol composition and increased
Phytosterols occur in relatively high concentration
in the seeds of oilseed rape (Brassica napus L.).
However, little is known about genetic variation of
phytosterols and almost no data are available of the
impact of geographic location and agricultural
practices on the content and composition of
phytosterols in rapeseed. To improve the phtosterol
composition must be a major breeding aim for a high
quality vegatable oil production.
Abidi SL, List GR and Rennick KA. Effect of genetic
modification on the distribution of minor constituents in
canola oil. Journal of American Oil Chemists’ Society,
76: 463-467, 1999.
Appelqvist LAD, Kornfeldt, AK and Wennerholm JE.
Sterols and steryl esters in some brassica and Sinapis
Seeds. Phytochemistry, 20: 207-210, 1981.
Becker HC, Löptien H and Röbbelen G. Breeding: An
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