ArticlePDF Available

Abstract

Current textbooks give an inaccurate picture of the occurrence of cholesterol in plants and also of the role of plant sterols in the mammalian uptake of cholesterol. Keywords (Audience): General Public
www.JCE.DivCHED.org Vol. XX No. XX Month 200X Journal of Chemical Education 1
There is a widespread belief among the public and even
among chemists that plants do not contain cholesterol. This
error is the result (in part) of the fact that plants generally
contain only small quantities of cholesterol and that analyti-
cal methods for the detection of cholesterol in this range were
not well developed until recently (1). Another reason has to
do with the legalities of food labeling that allow small quan-
tities of cholesterol in foods to be called zero (2). The fact is
that cholesterol is widespread in the plant kingdom although
other related sterols, such as β-sitosterol (henceforth referred
to as sitosterol), generally occur in larger quantities. No cur-
rent biochemistry text that we have examined provides an
accurate account of cholesterol in plants. Here is a suggested
paragraph for the next generation of biochemistry texts:
More than 250 steroids have been described in plants (3).
Of these, perhaps sitosterol, which differs from choles-
terol by an ethyl substituent at position 24, is the most
common. But plants also contain cholesterol both free
and esterified. Cholesterol occurs as a component of plant
membranes and as part of the surface lipids of leaves
where it is sometimes the major sterol. The quantity of
cholesterol is generally small when expressed as percent
of total lipid. While cholesterol averages perhaps 50
mgkg total lipid in plants, it can be as high as 5 gkg
(or more) in animals.
A sample of current biochemistry textbooks shows that the
question of cholesterol in plants is, at best, treated in a mis-
leading way.
“Cholesterol...is only rarely found in plants.” (4) (False)
“Similar [to cholesterol] sterols are found in other eu-
caryotes: stigmasterol in plants.” (5) (True , but mislead-
ing)
Plant cell membranes have no cholesterol. (6) (False)
Related [to cholesterol] sterols are present in plant mem-
branes. (7) (True, but misleading)
Cholesterol is absent from prokaryotes but is found to
varying degrees in virtually all animal membranes. (8)
(True, but why are plants not even mentioned?)
Plants contain little cholesterol. (True) Rather, the most
common sterol components of their membranes are stig-
masterol and beta-sitosterol. (Not quite right, see Table
1). (12)
In addition, only Garrett and Grisham (13) discuss the
interesting question of the effects of plant steroids on cho-
lesterol levels in humans. Although evidence for these effects
has been in the literature for some time, a number of other
commonly used textbooks make no mention either of the
occurrence of cholesterol in plants nor of the effects of plant
sterols on cholesterol metabolism in humans.
Cholesterol and Plants
E. J. Behrman* and Venkat Gopalan
Department of Biochemistry, The Ohio State University, Columbus, OH 43210; *
Behrman.1@osu.edu
Concepts in Biochemistry edited by
William M. Scovell
Bowling Green State University
Bowling Green, OH 43403
stnalPniloretselohCfonoitubirtsiDralullecbuS.1elbaT
ecruoS loretselohceerF )%(
a
loretselohC )%(sretse ecnerefeR
b
sevaelnaebneerG
elohw119
stsalporolhc4233
airdnohcotim------
semosorcim182
sevaelnaebdetaloitE
elohw6329
stsalporolhc7262
airdnohcotim------
semosorcim643
stoohseziamyad-12fosellenagrO
c
ielcun226701
stsalporolhc225
airdnohcotim123
semosorcim123
a
.sloretslatotfotnecreP
b
ferees,ataderomroF .11
c
dnanoitcarfretseloretslatotehtfo%27erewsloretslyhtemed-4ehT noitcarfloretseerfehtfo%5
sliOtnalPemoSfotnetnoCloretselohC.2elbaT
ecruoS /loretselohC gkgm(
1
)ecnerefeR
liomlaP0241
liomlaP611
lenrekmlaP711
liotunocoC411
liodeesnottoC541
lionaebyoS921
lionroC551
liotunaeP421
liodeesrewolfnuS411
lioalonaC351
lioodacovA03< 51
lioevilO25.0 71,61
lioemaseS1.ac 71,61
N
ETO
:ehtevahsmalcdna,krop,rettub,kloygge,sniarb,tsartnocyB ,02:)gk/gni(ylevitcepsertnetnocloretselohcetamixorppagniwollof 5.0dna,6.0,5.2,51 .)81(
2Journal of Chemical Education Vol. XX No. XX Month 200X www.JCE.DivCHED.org
Data and Discussion
Occurrence
The quantity of cholesterol in a number of common veg-
etable (plant) oils is given in Table 2. According to FDA rules,
cholesterol quantities less than 2 mgserving may be labeled
as zero (19). The reader should check the label on whatever
oil is currently on the shelf. Caveat emptor. It is clear that
cholesterol and its esters are important constituents of plant
membranes and that this has been known for more than thirty
years. Table 2 also gives some data on the sterol fraction of
some plant organelles.
While cholesterol is usually a minor constituent of the
sterol fraction in plants, it is the major constituent of some
plant surfaces. The cholesterol and sitosterol makeup of the
sterol fraction of various canola surfaces is shown in Table 3.
The proportion of cholesterol in the sterol fraction of the
genera Liliaceae, Solanaceae, and Scrophulariaceae is espe-
cially large (Itoh et al. in refs 3 and 22)
Cholesterol and Plant Sterols
There is considerable interest in plant sterols owing to
their cholesterol-lowering effects. While Garrett and Grisham
(13) are to be commended for elaborating on this matter in
their textbook, their descriptions are incorrect and likely to
cause misunderstanding.
Despite their [plant sterols] structural similarity to cho-
lesterol, minor isomeric differences and/or presence of
methyl and ethyl groups in the side chains of these sub-
stances result in their poor absorption by intestinal mu-
cosal cells. Interestingly, although plant sterols are not
effectively absorbed by the body, they nonetheless are
highly effective in blocking the absorption of cholesterol
itself by intestinal cells.
This paradox is attributable to inaccuracies in the above state-
ments.
A typical western diet contains 400–600 mg cholesterol
and 200–400 mg plant sterols (sitosterol and campesterol)
per day. While 40–60% of the cholesterol is absorbed, less
than 20% of campesterol and less than 5% of sitosterol are
absorbed (23). Current models (24) propose the initial up-
take of cholesterol and plant sterols from the intestine into
the enterocyte (intestinal mucosal cell) by a common trans-
porter (called NPC1L1) expressed at the lumenal surface.
Subsequently, by mechanisms that are still unknown, sort-
ing of these various sterols takes place inside the enterocyte
with the majority of cholesterol being transferred to chylo-
microns and most of the plant sterols selectively pumped back
into the intestine by two ATP-dependent transporters (called
ABCG5 and ABCG8). This means that the discrimination
is by a selectivity of egress not ingress. This provides a basis
for understanding sitosterolemia, a rare inherited disease in
which there is hyper-absorption of plant sterols from the small
intestine. Sitosterolemic individuals absorb cholesterol and
plant sterols (presumably using NPC1L1) but are unable to
re-transport sitosterol into the intestine owing to mutations
in ABCG5 or ABCG8 (24).
Although plant sterols are not absorbed by the body as
effectively as cholesterol, they are absorbed (23). The choles-
terol-lowering effects of plant sterols (and their esters) are due
in part to their competition with cholesterol for packaging
into mixed micelles that are taken up by NPC1L1.
Acknowledgments
We thank Melvin Pascall for ref 19 and Wesley Harnish
for an essential stimulus.
Literature Cited
1. Rossell, J. B. In Analysis of Oilseeds, Fats, and Fatty Foods;
Rossell, J. B., Pritchard, J. L. R., Eds.; Elsevier: London, 1991;
Chapter 7, Table 7.11.
2. Moreau, R. A.; Whitaker, B. D.; Hicks, K. B. Prog. Lipid Res.
2002, 41, 457–500.
3. Akihisa, T.; Kokke, W. C. M. C.; Tamura, T. In Physiology
and Biochemistry of Sterols; Patterson, G. W., Nes, W. D., Eds.;
American Oil Chemists’ Society: Champaign, IL, 1991; Chap-
ter 7.
4. Horton, H. R.; Moran, L. A.; Ochs, R. S.; Rawn, J. D.;
Scrimgeour, K. G. Principles of Biochemistry, 3rd ed.; Prentice
Hall: Upper Saddle River, NJ, 2002; p 275.
5. Nelson, D. L.; Cox, M. M. Lehninger Principles of Biochemis-
try, 3rd ed.; Worth Publishers: New York, 2000; p 376.
6. Zubay, G. L.; Parson, W. W.; Vance, D. E. Principles of Bio-
chemistry; W. C. Brown: Dubuque, IA, 1995; p 385.
7. Metzler, D. E. Biochemistry, 2nd ed.; Academic Press: San Di-
ego, 2001; Vol. 1, p 392.
8. Berg, J. M.; Tymoczko, J. L.; Stryer, L. Biochemistry, 5th ed.;
Freeman: New York, 2002; p 325.
9. Brandt, R. D.; Benveniste, P. Biochim. Biophys. Acta 1972, 282,
85–92.
10. Kemp, R. J.; Mercer, E. I. Biochem. J. 1968, 110, 119–125.
11. Mudd, J. B. In The Biochemistry of Plants, Stumpf, P. K.;
Conn, E. E. Eds.; Vol. 4, Academic Press, New York, 1980,
pp. 514-515.
12. Voet, D.; Voet, J. G. Biochemistry, 3rd ed.; Wiley: New York,
2004; Vol. 1, p 389.
13. Garrett, R. H.; Grisham, C. M. Biochemistry; Brooks-Cole:
Belmont, CA, 2005; p 263.
14. Gurr, M. I. Role of Fats in Food and Nutrition, 2nd ed.; Elsevier:
London, 1992; p 36.
(epaRfotnetnoCloretS.3elbaTC)alona
ecruoS)%(loretselohC)%(loretsotiS
sevaeL
ecafrus5.176.0
ralullecartni5103
sdeeS
ecafrus2.726
ralullecartni7.076
sdopdeeS
ecafrus5312
NETO :ehtnoataD.sloretslatotfotnecrepsanevigsiataD ,hsidar,keel,egabbacfosdipilecafrusehtfotnetnocloretselohc elbaliavaoslareppepneergdna,arko,hcanips .)02( oslaeraerehT tnalpgnirudoitarloretsotis/loretselohcehtnisegnahcegral fer(tnempoleved 12 .)nierehtsecnereferdna
www.JCE.DivCHED.org Vol. XX No. XX Month 200X Journal of Chemical Education 3
15. Itoh, T.; Tamura, T.; Masumoto, T.; Dupaigne, P. Fruits 1975,
30, 687–695.
16. Castang, J. Ann. Falsif. Expert. Chim. 1981, 74, 697–700.
17. Kochhar, S. P. Prog. Lipid Res. 1983, 22, 161–188, Table 2.
18. Sabine, J. R. Cholesterol; Dekker: New York, 1977; p 59.
19. Title 21 of the Code of Federal Regulations (21 CFR), sec-
tion 101.62(d). http://vm.cfsan.fda.gov/~lrd/CF101-62.HTML
(accessed Aug 2005).
20. Noda, M.; Tanaka, M.; Seto, Y.; Aiba, T.; Oku, C. Lipids,
1998, 23, 439–444.
21. Hobbs, D. H.; Hume, J. H.; Rolph, C. E.; Cooke, D. T.
Phytochem. 1996, 42, 335–339.
22. Hartmann, M.-A. In Lipid Metabolism and Membrane Biogen-
esis; Daum, G., Ed.; Springer: Berlin, 2004; Chapter 5.
23. Klett, E. L.; Patel, S. B. Science 2004, 303, 1149–1150. Berge,
K. E.; Tian, H.; Graf, G. A.; Yu, Y.; Grishin, N. V.; Schultz,
J.; Kwiterovich, P.; Shan, B.; Barnes, R.; Hobbs, H. H. Sci-
ence 2000, 290, 1771–1775.
24. Lutjohann, D.; Bjorkhem, I.; Beil, U. F.; von Bergmann, K.
J. Lipid Res. 1995, 36, 1763–1773.
... Foods of plant origin have lower calorie density than foods of animal origin (Table 1). In addition, food from plant sources contains no cholesterol [23,67] or only traces of cholesterol [68]. In the article "Cholesterol and Plants", E. J. Behrman and Venkat Gopalan explain that plants may contain not only phytosterols but also cholesterol (which is considered a zoosterol). ...
... Moreover, according to FDA rules, cholesterol quantities <2 mg per serving may be labeled as "no cholesterol" or "zero cholesterol". E. J. Behrman and Venkat Gopalan also give a very good explanation for the cholesterol-lowering effects of phytosterols (plant sterols): phytosterols compete with cholesterol for packaging into the mixed micelles that are taken up by the polytopic transmembrane protein, Niemann-Pick C1-Like 1 (NPC1L1) [68]. Vegan diets are also associated with improved gut microbiota symbiosis, increased insulin sensitivity, reduced trimethylamine-N-oxide (TMAO), activation of peroxisome proliferator-activated receptors (PPARs), and overexpression of mitochondrial uncoupling proteins [16,24,48]. ...
... The consumption of raw fruits, vegetables, roots, nuts, and germinated seeds provides an intake of carotenoids, vitamin C, vitamin E, and other compounds that have an antioxidant effect. 3. Lipid-lowering effects-the absence [23,67] or limited intake of dietary cholesterol [68]. Moreover, some plants that are rich in sterols and stanols may lower serum low- [37,38]. ...
Full-text available
Article
Abstract: According to the World Health Organization, obesity has nearly tripled since the 1970s. Obesity and overweight are major risk factors for cardiovascular diseases, diabetes, inflammatory‐ mediated diseases, and other serious medical conditions. Moreover, recent data suggest that obesity, overweight, diabetes, and cardiovascular diseases are risk factors for COVID‐19‐related mortality. Different strategies for weight control have been introduced over the last two decades. Unfortunately, these strategies have shown little effect. At the same time, many studies show that plants might be the key to a successful strategy for weight control. Following the PRISMA guidelines for conducting systematic reviews, a search was conducted in PubMed, Web of Science, Scopus, and Embase using the following keywords: obesity, globesity, vegan, plant‐based diet, etc. Our results show that vegan diets are associated with improved gut microbiota symbiosis, increased insulin sensitivity, activation of peroxisome proliferator‐activated receptors, and over‐expression of mitochondrial uncoupling proteins. The key features of this diet are reduced calorie density and reduced cholesterol intake. The combination of these two factors is the essence of the efficiency of this approach to weight control. Our data suggest that plant‐based/vegan diets might play a significant role in future strategies for reducing body weight.
... We detected up to 0.8% β-sitosterol (w/w) in the corn silage feedstocks of our investigated agricultural biogas plants, which is well in the range 0.2%-2% β-sitosterol (w/w) that are typically found in different parts of the corn plant (Bacchetti et al., 2011;Harrabi et al., 2008;Ryan et al., 2007;Zhang et al., 2017). Conversely, we detected no or only small amounts of cholesterol in the plant-based feedstock fraction which is consistent with the minor role that cholesterol plays in the sterol pool of most plants (Behrman & Gopalan, 2005;Sonawane et al., 2017). However, we detected up to 0.2% cholesterol in the active methanogenic sludge and the digestate of the investigated agricultural biogas plants, which was presumably introduced by the 20%-60% pig and cattle manure feedstocks (Tyagi et al., 2007). ...
Full-text available
Article
Every year, several million tonnes of anaerobic digestate are produced worldwide as a by-product of the biogas industry, most of which is applied as agricultural fertilizer. However, in the context of a circular bioeconomy, more sustainable uses of residual digestate biomass would be desirable. This study investigates the fate of the sterol lipids β- sitosterol and cholesterol from the feedstocks to the final digestates of three agricultural and one biowaste biogas plants to assess if sterols are degraded during anaerobic digestion or if they remain in the digestate, which could provide a novel opportunity for digestate cascade valorization. Gas chromatographic analyses showed that feedstock sterols were not degraded during anaerobic digestion, resulting in their accumulation in the digestates to up to 0.15% of the dry weight. The highest concentrations of around 1440 mg β- sitosterol and 185 mg cholesterol per kg dry weight were found in liquid digestate fractions, suggesting partial sterol solubilization. Methanogenic batch cultures spiked with β- sitosterol, cholesterol, testosterone and β- oestradiol confirmed that steroids persist during anaerobic digestion. Mycobacterium neoaurum was able to transform digestate sterols quantitatively into androstadienedione, a platform chemical for steroid hormones, without prior sterol extraction or purification. These results suggest that digestate from agricultural and municipal biowaste is an untapped resource for natural sterols for biotechnological applications, providing a new strategy for digestate cascade valorization beyond land application.
... The main differences between CPO and CPKO are in colour, with CPO being naturally reddish-brown due to a high beta-carotene content [60]. CPO is a highly saturated vegetable fat that is semisolid at room temperature [61]. However, refined, neutralised, bleached, and deodorised CPO is a common commodity known as RBDPO and does not consist of carotenoids [62]. ...
Full-text available
Article
Alternative transformer oil has been investigated universally in past years. Different types of vegetable oil have been proposed and evaluated as replacements for conventional transformer oil (mineral oil) due to increasing exploitation and depleting petroleum reserves. In response to growing concern about global environmental and sustainable issues, this article discusses the suitability of palm oil (PO) and palm oil-based nanofluids (PO-N) as alternative transformer oils. A brief discussion of environmental concerns is provided in this paper, and the detailed properties of PO are thoroughly addressed. The electrical performance (alternating current breakdown voltage and lightning impulse breakdown voltage), physical behaviour (viscosity, flash point, and fire point), tan delta, and relative permittivity of PO and PO-N are also discussed in this paper. Based on reliable data and research, it has been proven that refined, bleached, deodorised palm oil (RBDPO) has been determined to be the most promising type of PO when compared to others. Furthermore, when CuO nanoparticles are added to RBDPO with the use of CTAB surfactant, the AC breakdown voltage increases by 173.42 % compared to RBDPO without CuO. However, there is still scope for further improvement in nanofluid stability. In addition to these studies, future research should focus on other aspects such as ageing studies, partial discharge breakdown voltage, etc. PO has interesting properties that make the industry and scientific community take notice.
... Cocoa butter, cocoa paste, and soy lecithin contained cholesterol amounts of 24.46 ± 0.78, 42.69 ± 0.84 and 30.23 ± 0.76 μg/g, respectively. This is confirmed by previous reports showing how cholesterol, differently from the common belief, is also present in plant-based ingredients, although in much lower amounts [40,41]. Non-enzymatic COPs were also present, reaching concentrations of 88.17 ± 2.81, 162.50 ± 3.71 and 103.86 ± 3.79 ng/g, with 7βOHC and 7KC being once again the most represented (71-85% of total non-enzymatic COPs). ...
Full-text available
Article
Cholesterol oxidation products (COPs) of non-enzymatic origin are mainly found in meat, fish, eggs and milk, mostly originating from the type of feeding, processing and storage. To verify the significance of COPs as biomarkers of cholesterol autoxidation and milk freshness, we quantified them in chocolates containing whole milk powders (WMPs) of increasing shelf-lives (i.e. 20, 120, and 180 days). Non-enzymatic total COPs (both free and esterified) ranged from 256.57 ± 11.97 to 445.82 ± 11.88 ng/g, increasing proportionally to the shelf-life of the WMPs, thus reflecting the ingredients' freshness. Based on the expected theoretical COPs, the effect of processing was quantitatively less significant in the generation of oxysterols (41-44%) than the contribution of the autoxidation of the WMPs over time (56-59%), pointing to the shelf-life as the primary determinant of COPs. Lastly, we quantified COPs of major commercial milk chocolates on the Italian market, which followed a similar distribution (from 240.79 ± 11.74 to 475.12 ± 12.58 ng/g). Although further replications of this work are needed, this study reports preliminary results and a practical example of a first application of non-enzymatic COPs as markers to further quantify and characterize the nutritional quality and freshness, not only of ingredients but also of composite products.
... -Sitosterol is believed to have antidiabetic properties ( Balamurugan et al. 2011 ;Tripathi et al. 2013 ), whereas stigmasterol acts as a precursor in the synthesis of progesterone and is also known as an intermediate product in biosynthesis of vitamin D3, estrogen, androgen and corticoids ( Chaudhary et al. 2011 ;Gabay et al. 2010 ). Estimate around 200-400 mg of sitosterol and campesterol have been consumed in the daily western diet, and the intestine absorption of campesterol is higher than sitosterol ( Behrman and Gopalan, 2005 ). However, the differences in metabolite profile between L. minor and W. globosa are not well understood. ...
Full-text available
Article
Duckweed species are nutritionally meaningless plant which grow wildly in unattended areas. Therefore, understanding the metabolites content in duckweed species is essential for designing a future food products. Here, we report an untargeted Gas Chromatography-Mass Spectrometry (GC-MS)-based metabolomics approach for comprehensively discriminating between Lemna minor and Wolffia globosa of duckweeds species using principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). Ten differential metabolites levels were tentatively identified between L. minor and W. globosa. Relative to W. globosa, L. minor appeared to enrich with 5-Hydroxyl-L-tryptophan, Tocopheryl acetate, Naringenin, α-linolenic acid and glutamic acid. Furthermore, the nutritional and microbial analyses of ice cream formulated with dried L. minor were investigated. The nutritional analysis results show that relative to control, the ice cream with 2% dried L. minor had significantly increased protein, fiber and ash content. In addition, total plate count (TPC) for microbial analysis of duckweed ice cream was performed. The result suggested that the small amount of bacteria (3.82 cfu/g) was traced in formulated ice cream with 2% dried L. minor. Overall, the metabolites profile, nutritional and microbial analyses of food used L. minor plant indicate that duckweed is a good candidate for future food.
... Perhaps surprisingly, and contrary to the common belief, cholesterol is also present in plant-based ingredients, although in much lower amounts compared to animal-based ones [128,129]. Consequently, COPs can also be found in plant-based products. However, only a handful of studies has quantified oxysterols in such products. ...
Full-text available
Article
More and more attention is nowadays given to the possible translational application of a great number of biochemical and biological findings with the involved molecules. This is also the case of cholesterol oxidation products, redox molecules over the last years deeply investigated for their implication in human pathophysiology. Oxysterols of non-enzymatic origin, the excessive increase of which in biological fluids and tissues is of toxicological relevance for their marked pro-oxidant and pro-inflammatory properties, are increasingly applied in clinical biochemistry as molecular markers in the diagnosis and monitoring of several human and veterinary diseases. Conversely, oxysterols of enzymatic origin, the production of which is commonly under physiological regulation, could be considered and tested as promising pharmaceutical agents because of their antiviral, pro-osteogenic and antiadipogenic properties of some of them. Very recently, the quantification of oxysterols of non-enzymatic origin has been adopted in a systematic way to evaluate, monitor and improve the quality of cholesterol-based food ingredients, that are prone to auto-oxidation, as well as their industrial processing and the packaging and the shelf life of the finished food products. The growing translational value of oxysterols is here reviewed in its present and upcoming applications in various industrial fields.
... These observations suggest that cholesterol may act as a direct precursor to diosgenin biosynthesis in plants. However, although cholesterol makes up a large fraction of the total sterol contents in some plant species, such as Canola, Solanaceae, Liliaceae, Scrophulariaceae, and Cucurbita maxima (Garg and Nes, 1984;Garg and Nes, 1987;Behrman and Gopalan, 2005), it is indeed a minor sterol in the several diosgenin-producing species with its concentration usually being much lower than that of diosgenin by orders of magnitude (Cerdon et al., 1995;Sun et al., 2017). On the other hand, 24-alkyl sterols, such as β-sitosterol, are biosynthesized at comparable levels with diosgenin in vivo (Cerdon et al., 1995;Sun et al., 2017). ...
Full-text available
Article
Diosgenin serves as an important precursor of most steroidal drugs in market. Cholesterol was previously deemed as a sterol origin leading to diosgenin biosynthesis. This study reports that cholesterol is not in parallel with diosgenin biosynthesis in Trigonella foenum-graecum . We first perturbed its sterol composition using inhibitors specific for the upstream isoprenoid pathway enzymes, HMGR (3-hydroxy-3-methylgutaryl-CoA reductase) on the mevalonate (MVA) and DXR (1-deoxy-D-xylulose-5-phosphate reductoisomerase) on the 2-C-methyl-D-erythritol-4-phophate (MEP) pathways, and have revealed that diosgenin and cholesterol reversely or differently accumulated in either the MVA or the MEP pathway-suppressed plants, challenging the previously proposed role of cholesterol in diosgenin biosynthesis. To further investigate this, we altered the sterol composition by suppressing and overexpressing the 24-sterol methyltransferase type 1 (SMT1) gene in T. foenum-graecum , as SMT1 acts in the first committed step of diverting the carbon flux of cholesterol toward biosynthesis of 24-alkyl sterols. Knockdown of TfSMT1 expression led to increased cholesterol level but caused a large reduction of diosgenin. Diosgenin was increased upon the TfSMT1 -overexpressing, which, however, did not significantly affect cholesterol biosynthesis. These data consistently supported that diosgenin biosynthesis in T. foenum-graecum is not associated with cholesterol. Rather, campesterol, a 24-alkyl sterol, was indicative of being correlative to diosgenin biosynthesis in T. foenum-graecum .
... The differential complementation capacity of these two sterols might be due to the fact that stigmasterol is the most abundant sterol in tobacco cellular membranes (Cassim et al. 2019), and/or to the differential effects of these two sterols on membrane organization and biophysical properties (Grosjean et al. 2015). In contrast to other organisms, plants contain a mixture of sterols consisting of a variety of minor biosynthetic intermediates and three major ∆ 5 -sterols, usually β-sitosterol, stigmasterol and campesterol (Moreau et al. 2002) (Fig. 2), although cholesterol is also a major sterol in some members of the Liliaceae, Solanaceae and Scrophulariaceae families (Behrman and Gopalan 2005) while ∆ 5 -avenasterol is a major sterol in oats (Moreau et al. 2002) and ∆ 7 -sterols are the predominant sterols in the Cucurbitaceae family (Akihisa et al. 1986;Fenner et al. 1989). Several studies have reported remarkable differences in the capacity of phytosterols to promote the formation of ordered domains in the membrane and organize their spatial distribution at the membrane surface. ...
Full-text available
Article
The genome of most plant viruses consists of a single positive-strand of RNA (+ ssRNA). Successful replication of these viruses is fully dependent on the endomembrane system of the infected cells, which experiences a massive proliferation and a profound reshaping that enables assembly of the macromolecular complexes where virus genome replication occurs. Assembly of these viral replicase complexes (VRCs) requires a highly orchestrated interplay of multiple virus and co-opted host cell factors to create an optimal microenvironment for efficient assembly and functioning of the virus genome replication machinery. It is now widely accepted that VRC formation involves the recruitment of high levels of sterols, but the specific role of these essential components of cell membranes and the precise molecular mechanisms underlying sterol enrichment at VRCs are still poorly known. In this review, we intend to summarize the most relevant knowledge on the role of sterols in ( +)ssRNA virus replication and discuss the potential of manipulating the plant sterol pathway to help plants fight these infectious agents.
Full-text available
Article
Aquatic ecosystems convey complex contaminant mixtures from anthropogenic pollution on a global scale. Point (e.g., municipal wastewater) and nonpoint sources (e.g., stormwater runoff) are both drivers of contaminant mixtures in aquatic habitats. The objectives of this study were to identify the contaminant mixtures present in surface waters impacted by both point and nonpoint sources, to determine if aquatic biota (amphibian and fish) health effects (testicular oocytes and parasites) occurred at these sites, and to understand if differences in biological and chemical measures existed between point (on-stream) and nonpoint sources (off-stream). To accomplish this, water chemistry, fishes, and frogs were collected from 21 sites in the New Jersey Pinelands, United States. Off-stream sites consisted of 3 reference and 10 degraded wetlands. On-stream sites consisted of two reference lakes and six degraded streams/lakes (four sites above and two sites below wastewater outfalls). Surface water was collected four times at each site and analyzed for 133 organic and inorganic contaminants. One native and five non-native fish species were collected from streams/lakes and native green frogs from wetlands (ponds and stormwater basins). Limited differences in contaminant concentrations were observed in reference and degraded wetlands but for streams/lakes, results indicated that landscape alteration, (upland agricultural and developed land) was the primary driver of contaminant concentrations rather than municipal wastewater. Incidence of estrogenic endocrine disruption (intersex) was species dependent with the highest prevalence observed in largemouth bass and black crappie and the lowest prevalence observed in green frogs and tessellated darters. Parasite prevalence was site and species dependent. Prevalence of eye parasites increased with increasing concentrations of industrial, mycotoxin, and cumulative inorganic contaminants. These findings are critical to support the conservation, protection, and management of a wide range of aquatic species in the Pinelands and elsewhere as habitat loss, alteration, and fragmentation increase with increasing development.
Full-text available
Article
Absorption of dietary cholesterol, campesterol, and sitosterol, cholesterol balance, and fecal excretion of plant sterols were determined in three unrelated patients with phytosterolemia and three healthy volunteers during constant intake of cholesterol and plant sterols using accurate gas-liquid chromatography-mass spectrometry techniques. Each subject received a mixture of [26,26,26,27,27,27-2H6]cholesterol, [6,7,7-2H3]sitostanol, and [6,7,7-2H3]campesterol together with two non-absorbable markers, [5,6,22,23-2H4]sitostanol and chromic oxide. Feces were collected from days 5 to 7 and absorption of different sterols was calculated from the intestinal disappearance of the different sterols relative to [5,6,22,23-2H4]sitostanol and chromic oxide. The results obtained by the two markers were not different and the absorption of cholesterol averaged 53 +/- 4% for the patients (mean +/- SD) and 43 +/- 3% for the volunteers. Campesterol absorption averaged 24 +/- 4% in patients and 16 +/- 3% in healthy volunteers, whereas sitosterol absorption averaged 16 +/- 1% and 5 +/- 1%, respectively. Cholesterol synthesis expressed by body weight varied considerably in the two groups but appeared to be about 5 times lower in patients than in controls. Administration of a high dose of sitostanol (0.5 g t.i.d.) to two patients was followed by a reduction in cholesterol absorption by 24% and 44%, an increase in fecal output of cholesterol and steroids derived from cholesterol and plant steroids, and a marked reduction of serum cholesterol, campesterol, and sitosterol. Under the conditions used, inhibition of cholesterol absorption by sitostanol was not followed by a significant rise in cholesterol synthesis. The time of observation was, however, too short to allow final conclusion on this. The results show that the absolute difference in absorption rate of different sterols between the patients and healthy volunteers was about the same. As a consequence, increasing hydrophobicity causes a relative decrease of absorption rates. Thus, patients with phytosterolemia seem to have a generally increased absorption of sterols rather than a loss of a specific discriminatory mechanism, and oral administration of sitostanol seems to be an interesting new approach for treatment of phytosterolemia.
Article
Apical tissues of Brassica campestris, grown under controlled environmental conditions, were analysed for their lipid content. The principal lipids were sterols, phospholipids and sphingolipids. The major sterols were identified as sitosterol, stigmasterol, campesterol and cholesterol, the phospholipids as phosphatidylethanolamine (PE) and phosphatidylcholine (PC), and the sphingolipids as cerebrosides. In the early stages of apical development, unusually high proportions of cholesterol and cerebrosides were found. However, their relative proportions gradually decreased as the apex developed; a concomitant increase in sitosterol was observed. These results suggested a specific association between these lipids and the development of the shoot apex. PE increased steadily during apical development, whereas PC increased more rapidly, but then declined at the later stage. The relative proportion of campesterol increased in the apex during the late stages of development and appeared to be involved in petal formation, which coincided with the decrease in PC.
Article
Cholesterol has been detected as one of the major sterols in the surface lipids of higher plant leaves. It was widely distributed among the plant leaves of various species as a common main sterol component with a few exceptions. The content of cholesterol amounted to 71.5% of the total sterols in the surface lipids of rape leaves. However, the proportion of cholesterol in the intracellular lipids of rape leaves was lower than that in the surface lipids, and the seed lipids contained only a trace amount of cholesterol, as reported in the literature. In the leaf surface lipids examined, a minor amount of cholestanol associated with cholesterol often was detected by capillary gas chromatography and gas chromatography-mass spectrometry. The related analysis for the surface lipids of fruits showed that cholesterol was one of the major component sterols also in those lipids of several species.
Article
Chloroplasts, mitochondria and microsomes were isolated from a cell-free extract of green and etiolated leaves of bean, by differential and sucrose or ficoll gradient centrifugation. The sterols and sterol esters of whole leaves and subcellular fractions were compared. The following sterols were identified from the leaves: cholesterol (cholest-5-en-3β-ol), Δ7-cholestenol (cholest-7-en-3β-ol), campesterol (), stigmasterol (), sitosterol (stigmast-5-en-3β-ol) and isofucosterol (). These sterols are present in all subcellular fractions but their concentrations differ significantly; in particular the chloroplasts and the mitochondria are much richer in cholesterol (24%) compared to the leaves (1%).The amount of sterols per mg of proteins in the fractions varied as follows: reticulum. Sterol esters were generally enriched in cholesterol (25–75%) and poor in stigmasterol (10%).These results are discussed in terms of the role of the sterols in the structure and function of plant cell membranes.
Article
1. The composition of the esterified and unesterified sterols of the nuclear, chloroplastidic, mitochondrial and microsomal fractions of 21-day-old maize shoots was examined. 2. The microsomal and mitochondrial fractions contain the bulk of the sterols of the tissue. 3. Only 1% of the sterol isolated from all the organelles is esterified. 4. The nuclear fraction has the greatest proportion of esterified sterol and the microsomal fraction the least. 5. 4-Demethyl sterols constitute the bulk of both esterified and unesterified sterols in all organelle fractions. 6. Cholesterol is the major esterified 4-demethyl sterol of the nuclear and chloroplastidic fractions, but only the nuclear fraction has an appreciable proportion of unesterified cholesterol. 7. Sterol esters of linolenic acid are more abundant in the mitochondrial and microsomal fractions than in the other two fractions.