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Glycoalkaloids, bitter tasting toxicants in potatoes: A review


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Potatoes make popular dishes among humans. Currently the fresh potato consumption is decreasing and most of the potatoes are converted to value added products to meet consumer demand. Glycoalkaloids are natural bitter tasting, heat stable toxicants present in potatoes. In the edible tuber, majority of these compounds are confined to the peel. High content of glycoalkaloids impart an off flavour to the potatoes and shown to be toxic to humans and animals. There have been food safety concerns linked with the potatoes and potato based products owing to the unacceptable glycoalkaloid content in the past. Thus the glycoalkaloid content is the major determinant of the quality and safety of edible potatoes. This review highlights major areas relevant to glycoalkaloids in potatoes such as distribution and accumulation in edible tubers, factors enhancing formation, effect of various cooking methods, toxic effects and measures to minimize the content to ensure consumer safety. Keywords: potato, glycoalkaloids, α-solanine, α-chaconine, bitter toxicants
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International Journal of Food Science and Nutrition
International Journal of Food Science and Nutrition
ISSN: 2455-4898
Impact Factor: RJIF 5.14
Volume 3; Issue 4; July 2018; Page No. 188-193
Glycoalkaloids, bitter tasting toxicants in potatoes: A review
Deepthi Inoka Uluwaduge1
1 Senior Lecturer, Department of Allied Health Sciences, Faculty of Medical Sciences, University of Sri Jayewardenepura,
Gangodawila, Nugegoda 10250, Sri Lanka
Potatoes make popular dishes among humans. Currently the fresh potato consumption is decreasing and most of the potatoes are
converted to value added products to meet consumer demand. Glycoalkaloids are natural bitter tasting, heat stable toxicants present
in potatoes. In the edible tuber, majority of these compounds are confined to the peel. High content of glycoalkaloids impart an off
flavour to the potatoes and shown to be toxic to humans and animals. There have been food safety concerns linked with the
potatoes and potato based products owing to the unacceptable glycoalkaloid content in the past. Thus the glycoalkaloid content is
the major determinant of the quality and safety of edible potatoes. This review highlights major areas relevant to glycoalkaloids in
potatoes such as distribution and accumulation in edible tubers, factors enhancing formation, effect of various cooking methods,
toxic effects and measures to minimize the content to ensure consumer safety.
Keywords: potato, glycoalkaloids, α-solanine, α-chaconine, bitter toxicants
Potato (Solanum tuberosum L.), a member of the Solanaceae
family, is a popular crop among different cultural back
grounds. It is well grown in majority of countries and
worldwide production stands in the fourth place among other
major crops wheat, maize and rice [1, 2]. From year 2005 the
potato production in developing countries exceeded that of the
developed countries [3]. At present China contributes to the
highest amount of the world’s production followed by India,
Russian Federation and United States [2]. It serves as a major
inexpensive low fat food source rich in energy [4]. Other
nutritional importance are supplementation of high quality
protein, fibre and vitamins [5, 6].
The potato tuber contains a natural bitter-tasting steroidal
toxicant known as glycoalkaloids [7]. These are nitrogen
containing secondary metabolites present in some members of
the Solanaceae family including potatoes, tomatoes and egg
plants [6, 8]. Low amounts of glycoalkaloids present in
commercial varieties impart the flavour to the potatoes [9].
However, potato has a bitter taste when the levels exceed
14mg/100g [5, 10].
Potato glycoalkaloids have shown to possess many health
benefits such as anticancer, antimalarial, anti-inflammatory,
hypoglycaemic and hypocholesterolaemic activities [5, 11, 12].
Glycoalkaloids have fungicidal and pesticidial properties and
it is one of the plants natural defences [4]. Synthesis is
significantly increased under unfavourable conditions, and it
may serves as a stress metabolite in the potato plant [5].
This review aims to provide a comprehensive summary of the
scientific literature on potato glycoalakaloids and their
biological role. Since there had been reports on incidental
poisoning of potatoes due to intolerable glycoalkaloid levels,
practical measures documented in this review are important to
improve the quality of edible tubers.
Chemical nature of glycoalkaloids in potatoes
The most important glycoalkaloids found in potato tubers are
α -solanine and α-chaconine, (Figure 1) comprising about 95%
of total glycoalkaloid content [1, 4, 13]. Solanine and chaconine
are nitrogen containing steroidal alkaloids, bearing the same
aglycone, solanidine but differ in the trisaccharide side chain
[1, 9, 14]. The trisaccharide in α - solanine is galactose, glucose
and rhamnose and that in α-chaconine is glucose and two
rhamnose residues [1, 14]. A minor percentage of glycoakaloids
(5%) contain β- solanine, γ- solanine, β-chaconine and γ-
chaconine [14].
Fig 1: The structure of glycoalkaloids α -solanine and α-chaconine
(R1= β-D-galactose, R2= β-D-glucose, R3= α-L-rhamnose for
α-solanine and R1= β-D-glucose, R2=R3=α-L- rhamnose for
Distribution of glycoalkaloids in potato plants
Glycoalkaloid content in various parts of the plant
These compounds are distributed throughout the potato plant
and the concentrations vary significantly depending on the
anatomical part or the genetic variety [1, 3, 15]. A broad range
for total glycoalkaloids for a given part of the plant was
reported by many studies owing to considerable variation of
the compound among potato plants [1, 13, 16, 17, 18]. Synthesis of
International Journal of Food Science and Nutrition
glycoalkaloids occur in all parts of the plant and the highest
concentrations have been reported in those parts with high
metabolic rates. Flowers (215-500 mg/100g), sprouts (200-
730 mg/100g) and young leaves (23-100 mg/100g) are
comparatively rich in glycoalakaloids [1, 16, 17, 18].
Glycoalkaloid content in the edible tuber
Most of the edible tubers contain low amount of
glycoalkaloids (less than 10 mg/100g fresh weight) [10]. The
profile of glycoalkaloids in each part of the tuber was not
revealed by most of the past records and the total
glycoalkaloid content was reported by many such studies [1, 13,
16, 17, 18, 19, 20]. However the content of α-chaconine is reported
to be slightly higher than α –solanine [13].
Glycoalkaloid content in commercial potato tubers are
comparatively lower and the distribution within the tuber is
not uniform. The highest levels are confined to the skin and
the peel while less amounts could be observed towards the
pith [13, 21]. The pith had undetectable levels of glycoalkaloids
indicating that the tubers are safe to consume though there had
been few reported occasions with banned levels of
glycoalkaloids in tubers [3, 22, 23]. These compounds are mainly
concentrated in the “eye” regions of the tuber and
consumption of potatoes rich in those parts may cause
potential health risks [13].
Small tubers are reported to be rich in glycoalkaloids on
weight for weight basis than larger ones [1]. Green potatoes
often show bitterness and this off flavour is due to the
accumulation of excess amounts of glycoalkaloids in the peel
[10]. Table 1 illustrates the distribution of glycoalakaloids in
various tuber tissues.
Table 1: Distribution of total glycoalkaloid content in various tuber
tissues of potato [16, 17, 18]
Part Total glycoalkaloid content (mg/100g fresh weight)
Whole tuber
Skin (2-3% of tuber) 30-64 Peel (10-12% of tuber)
Bitter tasting tuber
Peel from bitter tuber
Modern cultivars vs. wild progenitors
The glycoalkaloid levels in modern cultivars are much lower
than in wild progenitors and this information is useful for
commercial potato breeders [1]. These compounds are not
transported between various parts of the plant and therefore
the amount present in each part is propionate to synthesis [3].
Genetic engineering approaches could be useful for the
manipulation of the level of glycoalkaloids according to
commercial needs such as to reduce the levels in tubers to
enhance the edibility and the safety and to increase the content
in leaves to ensure the protection from diseases and predators [24].
Factors affecting levels of glycoalkaloids in the tuber
Both genetic and environmental factors have been shown to
affect the levels of glycoalkaloid in potato tubers.
External factors
Environmental factors during pre-harvest period
Several external factors during pre-harvest period (soil
composition and climate) and post-harvest events (effect of
light, temperature, storage time, humidity, mechanical injury
and sprouting) may increase the glycoalkaloid content [4, 16].
Exposure to light may stimulate chlorophyll synthesis leading
to ‘greening’ and those tubers are reported to be rich in
glycoalkaloids [25]. Extreme temperatures and dry or wet
growing seasons may influence the synthesis of glycoalkaloids
during growth of the plant [3, 25]. Water- logging and drought
stress are other environmental factors which could enhance
the production of glycoalkaloids in significant amounts in
some cultivars [26, 27]. It has been reported that a double
nitrogen rate during the cultivation increased glycoalkaloid
content by 10% in some varieties [28]. A perusal of literature
indicates that early harvested tubers may show cultivar
specific impacts on glycoalkaloid accumulation than late
harvested tubers [10, 23, 29].
Biodynamic conditions vs. classic cultivations
Studies conducted by Norgia et al., (2008) have revealed that
potato breeds grown in biodynamic conditions were rich in
glycoalkaloids and solanidine compared to the breeds grown
in classic conditions (5-15% increase) [14]. Biodynamic
conditions provide the natural environment in which potatoes
could develop healthy and be able to fight against detrimental
agents and therefore those varieties may have synthesized
more phytorepelents. Classic cultivation of potatoes involves
use of fertilizers and other chemicals according to the need
and therefore those varieties are protected artificially. Hence
the need of natural phytorepellents such as glycoalkaloids is
less. Home Guard potato tubers had higher glycoalkaloid
content and showed a little increase in response to adverse
environmental conditions [26].
Factors to be considered during post-harvest period
Tubers subjected to post- harvest stress factors such as
physical damage (cutting and bruising during harvest or
transit), microbial or herbivore attack, improper handling and
inadequate storage conditions are known factors which may
influence the content of these compounds in potato tubers [30].
Tubers which are exposed to the mentioned factors if used for
skin-on or peel based products have higher glycoalkaloid
levels and therefore cause potential health risks. However,
safe handling and monitoring of other storage conditions such
as temperature and light are important to improve the quality
of potatoes in commercial varieties.
Other contributing factors for glycoalkaloid synthesis
Ability to produce glycoalkaloid is inherited to potato
cultivars [10, 15, 31]. This information is useful for commercial
production of edible potato varieties with low content through
breeding and biotechnological methodologies, while potato
genotypes with high glycoalkaloid content may be developed
for the pharmaceutical purposes [15]. It is recommended to
grow potatoes with inherently low glycoalkaloid and to
protect them from other inducers of glycoalkaloid synthesis to
enhance the quality of the commercial potato destined for
consumption [10]. Breeding for new varieties to obtain
characteristics such as disease resistance and withstand with
cold and other major changes in agricultural practices should
be accompanied by careful control of the glycoalkaloid levels.
International Journal of Food Science and Nutrition
Regulatory control of the level of glycoalkaloids
The current safe level of glycoalkaloid in potatoes had set at
20mg/100g of fresh weight by several leading authorities and
if the threshold value is exceeded by any cultivar, those
varieties are not recommended for human consumption [32, 33].
Though the standard potato varieties with the acceptable
steroidal glycoalkaloid content have released to the
commercial producers for growing, occasionally the safe level
could be exceeded by several environmental, physical and
storage conditions as pointed out in the text. Two such
reported occasions are withdrawal of potato cultivars ‘Lenape
and Magnum Bonum from United State and Swedish
markets due to unacceptable glycoalkaloid levels. The
reported average in Lenape’ was 30mg/100g and that of
Magnum Bonum’ was 25.4/100g [3, 22, 23]. Therefore it is
advisable to monitor the steroidal glycoalkaloid content when
they have faced to adverse environmental conditions during
the tuber bulking and also to screen the amount of these
compounds in those batches before releasing them to the
market as a safety precaution. Further it is recommended to
assess the glycoalkaloid levels in potatoes generated from
breeding programs due to the genetic transmission of
undesirable levels of glycoalkaloids from wild species to
hybrid progeny without which it may result in wasted effort,
time and money [34].
Effect of processing on glycoalkaloid content of potatoes
Levels of glycoalkaloids in potato based products
Consumption of fried potato chips and crisps are being on the
rise in most of the countries due to its attractive flavour, easy
preparation and affordable price [21, 35]. Therefore recently
more attention has paid to evaluate the safety of potato based
products. According to Smith et al., (1996) potato chips (US
French fries) and potato crisps (US potato chips) normally
contain glycoalkaloid levels of 0.04-0.8 and 2.3-18 mg/100g
product respectively [1]. Further it is reported that the skin
based products such as fried skins and crisps are
comparatively rich in glycoalkaloids (56.7-145 and 9.5-72
mg/100g product respectively) [1]. Jacket potatoes and more
recently skin based preparations (potato crisps) have shown a
relatively high content of glycoalkaloids [1] According to the
reports by Mondy and Gosselin, (1988) “salt potatoes” (small
whole potatoes) are popular dishes among the consumers of
the North Eastern United State due to the belief that the peel
contains more nutrients [22]. Further, according to the
documentary evidence by, potatoes are processed with peel
into fried snack foods such as potato chips and kettle chips by
some Asian countries and may lead to ingestion of toxic
glycoalkaloids [33, 36].
Loss of glycoalkaloids during production of potato based
Production of French fries from potatoes involve several steps
such as cutting, blanching, drying and frying 35. During the
production chain, the highest amount of glycoalkaloids were
removed during peeling, blanching and frying and the French
fries ready for consumption contained 3-8% of glycoalkaloids
compared to raw material [35]. Similar findings have been
obtained by a study carried out to evaluate the quality of
French fries by Tajner-Czopek et al., (2008) and reported that
the highest decrease in glycoalkaloids was caused by frying,
which is the final step of processing (97.5% loss when
compared to raw unpeeled potatoes) [37]. The average loss
during other preliminary steps were 50%, 53% and 58% in
peeling, cutting and blanching respectively [38]. The level of
glycoalkaloids in potato granules were evaluated by Rytel
(2012) and reported that the highest decrease in glycoalkaloids
were caused by peeling (50%) and blanching (63%) and the
finished product had only 14% of the initial quantity [38].
Effect of in-home cooking methods on glycoalkaloid
Several studies suggest that peeling usually removes most of
the glycoalkaloids in the edible tubers. Sinden and Deahl
(1976) reported that up to 60% of the total glycoalkaloids in
whole tubers were removed with the peel [10]. Mondy and
Gosellin reported that potatoes cooked with peel were bitterer
than unpeeled potatoes due to the migration of glycoalkaloids
into the cortex during the cooking process, though they are
less mobile [22]. Similar findings have been obtained by
Tajner-Czopek et al., (2014) and the authors further claimed
that peeling removes higher amount of glycoalkaloids
(approximately twice) than cooking [37]. Bushway and
Ponnampalam (1981) investigated the stability of
glycoalkaloids during four cooking procedures; frying,
baking, microwaving and boiling [39]. A slight loss of
glycoalkaloids was shown by frying whereas the other
cooking methods which were tested did not significantly
reduce the glycoalkaloid content. In a similar study, it was
reported that the potato glycoalkaloids are relatively stable
under normal home cooking conditions revealing that only
little reduction was shown by boiling and microwave
treatment [40]. The study further suggested that the critical
temperature for decomposition of glycoalkaloids in potatoes
may be around 170° C based on the results obtained by using
deep frying at different temperatures (157°C, 170 °C and
260°C) [40].
Studies done to evaluate the effect of various processing
methods suggest that the glycoalkaloids are relatively stable
under conventional cooking procedures. In typical household
preparations, many Asians including Sri Lankans peel off the
potatoes after boiling. These compounds migrate into the
internal tissue of the tuber during boiling and therefore
conventional method of boiling reduces the quality of edible
potatoes. Thus it is advisable to remove the peel of the tubers
before any cooking process to reduce glycoalkaloids and to
improve the quality [40].
Toxicity caused by glycoalkaloids in potatoes
It is important to be aware on toxicity caused by potato
glycoalkaloids due to following reasons.
1. The potato makes a part of the regular diet of majority of
the people worldwide.
2. The concentration of glycoalkaloids present in potato has a
major economic impact on potato breeders since the potato
varieties exceeding the level of 20mg/100g fresh weight is
probably a rejection criteria in marketing [3, 22, 23].
3. According to the reported data by Smith et al. (1996),
modern preparations such as skin based products (crisps
and fried skins) may contain unacceptable levels of
International Journal of Food Science and Nutrition
glycoalkaloids (up to 72 mg/100g in crisps and 145
mg/100g in skin based products) and ingestion may elicit
health problems in humans [1]. A review of toxicological
literature by Zeiger (1998) reported that baked and fried
potato peels are a major source of large quantities of α -
solanine and α-chaconine in the diet [41].
Published toxicological findings on humans
The documented history of the steroidal glycoalkaloid
poisoning from potatoes extend up to year 1917 from Britain
on an outbreak of solanine poisoning by a hotel proprietor [42].
Baked potatoes with skins were identified as the causative
agent and the victims showed vomiting, diarrhoea and
abdominal pain [42]. A clinical observation was recorded by
Unverricht (1937) on an outbreak of sickness among
agricultural workers in a village near by Beriln [43]. Excluding
potatoes from the diet resolved the symptoms confirming that
the potatoes could be the causative agents for the illness. Mc
Millan and Thompson (1979) have reported an incidence of
poisoning among school boys caused by ingestion of potatoes
which had high amounts of α-solanine and α- chaconine [44].
Cumulative assessment of toxicological data suggests that
these compounds are toxic to humans at a very lower dose
when compared with other animal models [4].
Biological activities of glycoalkaloids
General symptoms of glycoalkaloid poisoning in humans are
nausea, vomiting, diarrhoea, stomach and abdominal cramps,
headache, fever, rapid and weak pulse, rapid breathing and
hallucination [3, 14]. Coma and death has been resulted in more
serious cases [1, 3]. There are two main biological functions of
glycoalkaloids [1, 3]. The first is their ability to bind with the
membrane sterols and there by cause the disruption of the
membrane architecture leading to leakage of cellular contents
raising gastrointestinal disturbances such as abdominal
cramps, vomiting and diarrhoea [1, 4, 45]. Differential diagnosis
of glycoalkaloid poisoning is complicated since the symptoms
of acute intoxication share common features of other gastro
intestinal disorders [1]. The other major biological action of
glycoalkaloid is the inhibition of acetylcholine esterase, the
enzyme involved in the hydrolysis of the neurotransmitter
acetylcholine at the cholinergic synapses. The anti-
acetylcholine esterase activity of glycoalkaloids is manifested
by neurological symptoms such as weakness, confusion and
depression [46].
Absorption vs. excretion
Absorption of potato glycoalkaloids in humans are apparently
proportional to the amount ingested [47]. An overview on the
toxicology of solanine (the major glycoalkaloid in potato)
compiled by Dalvi and Bowie (1983) revealed that solanine
when ingested is less toxic compared to the parenterally
administered solanine due to its poor absorption, rapid
excretion and conversion into less toxic secondary metabolites
in the stomach [48]. A controversial opinion regarding the
clearance of glycoalkaloids from the human body was
reported by Mensinga et al. in 2005 [49]. However, this
ascending dose study with human volunteers showed that the
clearance of glycoalkaloids from the body takes more than 24
hours and further suggested that there is a possibility of
accumulating the toxicants in case of daily consumption. The
observation by Mensinga et al. (2005) was further confirmed
by Nishie et al. (1971) reporting that once it is in the blood
stream, excretion appears to be low indicating that the
compounds might accumulate in various organs in the body
including liver by using animal models [49, 50].
Safe level of intake
Poisoning caused by glycoalkaloids on humans is subjected to
individual variations [1]. The toxic dose of glycoalkaloids in
humans is 1-5 mg/Kg body weight and lethal dose is 3-6
mg/Kg body weight when administered through the oral route
[1]. Therefore the USDA and other leading authorities have
defined a glycoalkaloid level of 20 mg/100g fresh weight and
100mg/100g dry weight as the safe limit in edible tubers [1, 3,
33]. Analysis of the toxicological data on human subjects failed
to establish a safe level of intake and further indicated that a
considerable effort is required to work out on such a cut off
value [13]. Due to variations of the glycoalkaloid content
according to pre harvest and post-harvest factors and the
individual variations of the toxic dose, it has been proposed
that the safety limit has to be brought down to a level less than
the recommended [20]. Commercial varieties tend to have
glycoalkaloid content less than the accepted safety limit of 20
mg/100g fresh weight [1]. It has been shown that the potato
tubers exceeding the glycoalkaloid level of 14mg/100g had
bitterness while a burning sensation in throat and mouth was
caused by tubers exceeding 22mg/100g [32]. Therefore the
quantity of glycoalkaloids present in edible tubers has a direct
impact on the quality of tubers. Since the off flavours caused
by high glycoalkaloid content will reduce the commercial
value of tubers, routine testing for glycoalkaloids are
necessary for the edible tubers and for potato based products
to ensure the safety of the consumer.
Published findings on animal experiments
Several laboratory experiments have shown that the
glycoalkaloids are toxic to animal models such as Syrian
Golden hamsters, rabbits, rats and mice [50, 51, 52, 53].
Experimental studies by Nishie et al. (1971) further confirmed
that the toxicological potency of the agyclone (solanidine) was
less when compared that with the solanine revealing that the
potential toxicity is mediated by the carbohydrate side chains
of the two compounds, α -solanine and α-chaconine [50]. The
acute toxicity studies have revealed that the LD50 for solanine
in mice is 32.3 mg/Kg BW and that of chaconine is 19.2
mg/Kg BW [13]. Oral administration of solanine to mice
showed less toxic effects (oral LD50 ≥1000 mg/KgBW) when
compared with that of the parenteral administration [47]. Rats
exhibited a comparatively higher toxic dose for solanine and
chaconine (65.6-107.5 mg/KgBW) when administered intra
peritonially [14]. Animal experiments suggest that α-chaconine
is more toxic than α-solanine [20, 50].
Measures to optimize the safety of edible tubers
Based on the scientific evidences, following recommendations
(Table 2) would be helpful for farmers and commercial
producers, retail sellers and consumers to improve the quality
of edible potatoes.
International Journal of Food Science and Nutrition
Table 2: Strategies for controlling glycoalkaloid formation/accumulation in potatoes and potato products
Farmers and
commercial producers
Selection of cultivars low in glycoalkaloids Careful manipulation of environmental factors (low temperature,
desired soil nitrogen content) Minimization of damage to tubers during post- harvest handling Screening for
glycoalkalod content of new varieties prior to market release
Retail sellers
Packing in opaque plastic films or paper bags (to protect from light) Rotate the stocks in retail displays Store in a
shaded, cold environment
Selection of intact tubers of moderate/large size Peel off the tuber before any processing method Eliminate use of
tubers with bitter taste and green colour
Potatoes, as a staple for humans have shown to be safe
throughout the long history of consumption despite the
presence of bitter tasting toxicants. Fortunately most of the
commercial potato varieties contain a glycoalkaloid level less
than 20mg/100g fresh weight (the acceptable upper safety
limit) in edible tubers. Processed potato products have
increased in popularity and therefore, from a food safety
perspective it is important that farmers and retailers review
their cultural and marketing practices in order to ensure that
the tubers contain a safe level of glycoalkaloids from the field
through storage and retail outlets to the table. In addition
selection criteria and processing methods adopted by
consumers are important to ensure the safety of edible tubers.
Declaration of interest
The author reports no conflicts of interest.
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... Plants have been known since prehistory to possess medicinal properties, hence their use in treating a plethora of diseases [1,2], including cancer. Even nowadays, with the advancement of synthetic compound technology, 41.9% of all new drugs approved from 1981 to 2019 were of natural origin or derived from natural products [3], whereas in 2010 alone, 61.7% of all natural medicinal compounds newly discovered were from higher plants [4]. Thus, the plant kingdom represents an important source of such compounds, especially if we consider that only 10% of all plant species were screened for their medicinal activity [5], with potentially many more to possess such properties. ...
... The S. bulbocastanum extract is richer in phenolic compounds, both in terms of their diversity and quantities (8-9 times higher concentration for the total polyphenolic content), but it has no glycoalkaloids, which are present in high concentrations in S. chacoense [26]. Taking into consideration the protective effects of phenolic compounds [40], and the known toxicity of potato glycoalkaloids [41] on human healthy cells, we hypothesize that these differences in the biochemical profile of the two species might be a starting point for explaining the differences observed regarding their toxic effects on healthy human endothelial cells. ...
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Solanum bulbocastanum is a wild potato species, intensively used in potato breeding programs due to its resistance to environmental factors. Thus, its biochemical profile and putative human health-related traits might be transferred into potato cultivars aimed for consumption. This study aims to assess the phytochemical profile and the selective cytotoxicity of an S. bulbocastanum extract against breast cancer cells. Dry leaves were subjected to ultrasonication-assisted extraction in methanol [70%]. The phenolic and glycoalkaloid profiles were determined by HPLC-PDA/-ESI+-MS. The volatile profile was investigated by nontargeted ITEX/GC-MS. The extract was tested against three breast cancer cell lines (MCF7, MDA-MB-231, HS578T) and a healthy cell line (HUVEC) by the MTT assay, to assess its selective cytotoxicity. The phenolic profile of the extract revealed high levels of phenolic acids (5959.615 µg/mL extract), and the presence of flavanols (818.919 µg/mL extract). The diversity of the volatile compounds was rather low (nine compounds), whereas no glycoalkaloids were identified, only two alkaloid precursors (813.524 µg/mL extract). The extract proved to be cytotoxic towards all breast cancer cell lines (IC50 values between 139.1 and 356,1 µg/mL), with selectivity coefficients between 1.96 and 4.96 when compared with its toxicity on HUVECs. Based on these results we conclude that the exerted cytotoxic activity of the extract is due to its high polyphenolic content, whereas the lack of Solanaceae-specific glycoalkaloids might be responsible for its high selectivity against breast cancer cells in comparison with other extract obtained from wild Solanum species. However, further research is needed in order to assess the cytotoxicity of the individual compounds found in the extract, as well as the anti-tumor potential of the S. bulbocastanum tubers.
... As a result of stress exposure in potatoes, abnormal amounts of other compounds are synthesized and many new or unusual compounds emerge, including glycoalkaloids (GA), in levels exceeding those found in healthy tissues [78,79]. These newly synthesized compounds play an important role in creating the natural resistance of tubers to diseases. ...
... On the one hand, this indicates a positive effect of the bacteria on the quality of stored products under normal storage conditions (when tubers are not infected with pathogens), and on the other hand, it indicates the possible involvement of GAs on potatoes resistance against tuber late blight upon application of B. subtilis 10-4 with SA. It is most likely that SA, as a signaling molecule, induces elevated GA accumulation (before stress), which plays an important role in the pre-adaptation of tubers to stresses [78,79]. Probably, this is one of the mechanisms which makes a contribution to the induction of the natural resistance of stored potatoes, which manifested in decreasing the disease development and keeping a healthy appearance of healthy and pathogen-infected potato tubers stored for six months ( Figure 1B). ...
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Potato (Solanum tuberosum L.) tubers are a highly important food crop in many countries due to their nutritional value and health-promoting properties. Postharvest disease caused by Phytophthora infestans leads to the significant decay of stored potatoes. The main objective of this study was to evaluate the effects of the endophytic bacteria, Bacillus subtilis (strain 10-4), or its combination with salicylic acid (SA), on some resistance and quality traits of stored Ph. infestans-infected potato tubers. The experiments were conducted using hydroponically grown potato mini-tubers, infected prior to storage with Ph. infestans, and then coated with B. subtilis, alone and in combination with SA, which were then stored for six months. The results revealed that infection with Ph. infestans significantly increased tuber late blight incidence (up to 90-100%) and oxidative and osmotic damage (i.e., malondialdehyde and proline) in tubers. These phenomena were accompanied by a decrease in starch, reducing sugars (RS), and total dry matter (TDM) contents and an increase in am-ylase (AMY) activity. Moreover, total glycoalkaloids (GA) (α-solanine, α-chaconine) notably increased in infected tubers, exceeding (by 1.6 times) permissible safe levels (200 mg/kg FW). Treatments with B. subtilis or its combination with SA decreased Ph. infestans-activated tuber late blight incidence (by 30-40%) and reduced oxidative and osmotic damages (i.e., malondialdehyde and pro-line) and AMY activity in stored, infected tubers. Additionally, these treatments decreased pathogen activated GA accumulation and increased ascorbic acid in stored tubers. Thus, the results indicated that endophytic bacteria B. subtilis, individually, and especially in combination with SA, have the potential to increase potato postharvest resistance to late blight and improve tuber quality in long-term storage.
... The dry matter content of tubers ranges from 17.0 to 25.7%, depending on [17,18]. The nutritional value of potato tubers is largely due to their chemical composition, and above all to the ingredients that are important in human nutrition (starch, total sugars and reducing sugars, protein, dietary fibre, vitamins, minerals) and the low content of harmful compounds (glycoalkaloids, nitrates pesticide residues) [5,16,19,20] ( Table 1). ...
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The potato is the basis of the human diet in most countries of the world and has a significant impact on human health. Therefore, the aim of the work was to draw attention to the potato as a source of nutrients and energy as well as bioactive compounds and to use them in human and animal nutrition, in pharmacy, medicine and cosmetology. A quantitative analysis of the scientific literature indicating the beneficial effect of potato in the daily diet was carried out. The search for nutrients and bioactive compounds was based on the Scopus database. Potato tubers have a strong prebiotic effect, as they lower the pH in the intestinal environment and have an immunomodulatory effect. These properties of potato are the basis for its use in the treatment of many diseases such as diabetes, obesity, hypertension, diseases of the nervous system and cancer. In addition, potato normalizes lipid metabolism disorders by lowering elevated cholesterol levels; is helpful in the treatment of type II diabetes by reducing elevated glucose levels; facilitates slimming processes (reduces body weight) and lowers the level of uric acid. Potato also has an immunostimulant effect, improving metabolism (in disorders of lipid metabolism), while in diseases of the cardiovascular system it regulates heart rhythm disorders, and is also used in limitingthe development of some malignant types of cancer. Prevents many chronic infectious diseases; chronic fatigue states; disorders of the intestinal microflora and the immune system.
... Lastly, hairy roots are a great platform for testing hypotheses. Mutagenesis of the St16DOX gene reduced steroidal glycoalkaoids (SGAs) which taste bitter and can be toxic (Uluwaduge et al., 2018). The NAC (NAM, ATAF1/2 and CUC2) transcription factor family is involved in plant development and Frontiers in Plant Science 03 ...
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While plants are an abundant source of valuable natural products, it is often challenging to produce those products for commercial application. Often organic synthesis is too expensive for a viable commercial product and the biosynthetic pathways are often so complex that transferring them to a microorganism is not trivial or feasible. For plants not suited to agricultural production of natural products, hairy root cultures offer an attractive option for a production platform which offers genetic and biochemical stability, fast growth, and a hormone free culture media. Advances in metabolic engineering and synthetic biology tools to engineer hairy roots along with bioreactor technology is to a point where commercial application of the technology will soon be realized. We discuss different applications of hairy roots. We also use a case study of the advancements in understanding of the terpenoid indole alkaloid pathway in Catharanthus roseus hairy roots to illustrate the advancements and challenges in pathway discovery and in pathway engineering.
... Bioactivities of glycoalkaloids have been reported to possess anticancer, anticholesterol, antimicrobial, anti-inflammatory, antinociceptive and antinopyretic effects (Siddique and Brunton 2019), but the steroidal glycoalkaloids (α-solanine and α-chaconine) of cultivated potato are toxic substances in high concentrations (Uluwaduge et al. 2018). The mechanism of toxicity induced by glycoalkaloids is associated with their membrane disruptive properties and their inhibition of acetylcholinesterase activity (Al Sinani and Eltayeb 2017). ...
Intraspecific somatic hybrids (CN1 and CN2) produced by protoplast fusion between dihaploid lines of potato cultivars Cardinal and Nicola were analysed in terms of their bioactive compounds and antioxidant activities. The total phenolic compound levels were investigated from the extracts derived from whole tubers using the Folin-Ciocalteu ethanol reagent method, which demonstrated that CN1 and CN2 hybrids contained higher levels of phenolics than the tubers of cv. Nicola. The corresponding extracts were also used for determination of the bioactivity levels, and an increased antioxidant capacity in the extracts of hybrid potato was revealed by DPPH and ABTS radical-scavenging tests compared to the tuber extracts of cv. Nicola. The identification of bioactive compounds in tubers was carried out separately for peel and flesh compartments to determine the phenolic compounds: phenolic acids by UHPLC-DAD and anthocyanins by HPLC–DAD and LC–MS. Glycoalkaloids were determined by UPLC-QTOF MS analysis. Phenolic acid profiling showed the presence of caffeic acid and three caffeoylquinic acid isomeric forms (3-CQA, 4-CQA and 5-CQA) in the peels, whereas only caffeic acid and 5-CQA (chlorogenic acid) were detected in the flesh compartments. The phenolic acid profiles of the somatic hybrids did not remarkably differ from the corresponding profiles of cv. Nicola. The colour-pigmented peels of the somatic hybrids were also analysed for their anthocyanin content, and six substances were identified, four of them were acylated glucosides of pelargonidin and peonidin by coumaric or ferulic acids. The increased antioxidative activities determined in the somatic hybrid tubers are most probably linked to their higher phenolic compound levels due to the pigmented tuber skin colour. The somatic hybrids had α-solanine and α-chaconine as the major glycoalkaloid compounds, and their total quantities were less than that found in tubers of cv. Nicola. This confirms the safety of the hybrid tubers for human consumption. © 2022, The Author(s), under exclusive licence to European Association for Potato Research.
... Кроме полезных для здоровья компонентов, картофель содержит гликоалкалоиды, которые являются сильнодействующими ядами [18]. Летальная доза этих компонентов составляет 3-5 мг/кг массы тела, а их воздействие на организм схоже с воздействием стрихнина или мышьяка [19]. ...
The article provides an overview of the current state of research in the field of requirements for the quality of potatoes for processing them into potato products. It is noted that the quality of potatoes with white pulp is determined by the mass fraction of: dry matter over 20 %; reducing sugars 0.2-0.5 %, glycoalkaloids no more than 200 mg/kg; starch not less than 16 %. For potatoes with pigmented pulp in addition to these indicators it is necessary to take into account the mass fraction of anthocyanins (over 0.5 %), which are effective antioxidants. The review presents the information on changes in the content of glycoalkaloids in potato tubers with pigmented pulp depending on the type of processing. The objective of experimental research is to analyze the qualitative indicators of native potato varieties with white and pigmented pulp to determine the practicability of their processing into potato products and further using as a starting material for selection. As research objects were selected 21 potato varieties with white pulp and 8 potato varieties with pigmented (colored) pulp. As a result of evaluation of the feasibility of using potatoes with white pulp 7 varieties out of 21 varieties of potatoes can be recommended for the production of potato products (Kamelot, Fritella, Rubin, Triumf, Ariya, Izyuminka, Mirazh). It is shown that the program «Statistica 12» can be used to assess the quality of potatoes on indicators of their suitability for processing into potato products. It was determined that the mass fraction of glycoalkaloids in the potato tuber is an important characteristic of the variety for its using in the production of potato products and as a table potato. Correlations between the mass fraction of potato dry matter and the mass fraction of glycoalkaloids (r = 0.47) and between the mass fraction of reducing sugars and the mass fraction of glycoalkaloids (r = 0.37) were established. The increasing in the mass fraction of these compounds is unwanted, and therefore, it is necessary to control their concentrations for choosing varieties for processing and as a starting material for the selection. Based on the analysis of the results of the evaluation of 8 experimental samples of potatoes with pigmented pulp, one sample was selected to be recommended for processing into potato products (VNIIKX-1), and two samples can be recommended as a starting material for the selection of table varieties with a high anthocyanin mass fraction (VNIIKX-4 and Indigo).
... Some of the toxic effects of glycoalkaloids are due to anticholinesterase effects on the central nervous system (Caprioli et al. 2014;Lelario et al. 2019) and disruption of cell membranes (Blankemeyer et al. 1998;Nepal and Stine 2019. Symptoms of glycoalkaloid poisoning in humans include colic pain in the abdomen and stomach, diarrhoea, vomiting, burning sensation about the lips and mouth, fever, rapid pulse and headache (Uluwaduge et al. 2018;Deng et al. 2021). Other destructive effects of glycoalkaloids include craniofacial malformations in hamsters (Gaffield and Keeler 1996;Ni et al. 2018;Kumar et al. 2019) and a variety of organ malformations in frog embryos and mealworms (Friedman et al. 1991;Chen et al. 2021). ...
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A new, fast and efficient method, hyphenated microwave-assisted aqueous two-phase extraction (MA-ATPE) was applied in the extraction of α-solanine from Solanum retroflexum. This environmentally friendly extraction method applied water and ethanol as extraction solvents. Central composite design (CCD) was performed which included numerical parameters such as time, mass of plant powder and microwave power. The categorical factors included the chaotrope-NaCl or the kosmotrope-Na 2 CO 3. Fitting the central composite design response surface model to the data generated a quadratic model with a good fit (R 2 = 0.920). The statistically significant (p < 0.05) parameters such as time and mass of plant powder were influential in the extraction of α-solanine. Quantification of α-solanine was achieved using a robust and sensitive feature of the ultra-high performance quadrupole time of flight mass spectrometer (UHPLC-qTOF-MS), multiple reaction monitoring (MRM). The optimized condition for the extraction of α-solanine in the presence of NaCl and Na 2 CO 3 was a period of 1 min at a mass of 1.2 g using a microwave power of 40%. Maximal extraction of α-solanine was 93.50 mg kg −1 and 72.16 mg kg −1 for Na 2 CO 3 and NaCl, respectively. The synergistic effect of salting-out and microwave extraction was influential in extraction of α-solanine. Furthermore, the higher negative charge density of the kosmotrope (Na 2 CO 3) was responsible for its greater extraction of α-solanine than chaotrope (NaCl). The shorter optimal extraction times of MA-ATPE make it a potential technique that could meet market demand as it is a quick, green and efficient method for removal of toxic metabolites in nutraceuticals.
CRISPR/Cas9 is a unique technology that has enabled researchers to edit genomes. The current study was conducted to investigate the efficiency of genome editing in diploid and tetraploid potato varieties. The stem internodes of AGB and M6 plants (5–6 weeks old) were infected with Agrobacterium strain LBA4404, harboring CRISPR/Cas9 vector, expressing a particular guide RNA against vacuolar invertase; and Cas9 endonuclease. Both tetraploid and diploid potatoes showed encouraging regenerative response on selection media. The transformation efficiency of 11.7% was obtained in potatoes in this study, whereas an indel% was found to be 6 for diploid and 5 for tetraploid variety via Sanger sequencing data. The regenerated plantlets were shifted to culture tubes where M6 diploid variety needed indole-3-butyric acid (IBA) for root development in comparison to tetraploid variety that rooted without IBA. All molecular analysis confirmed the integration of cassette and expression of Cas9 in primary transformants. Overall, the results concluded that the adopted transformation protocol regenerated plants with edited targeted genes that can be further used in an efficient potato breeding programme.
The study of biochemical quality indicators of 26 new potato hybrids was carried out in order to determine the ones mostly suitable for processing into starch and potato products and for use as table variety. An express method was used to determine dry matter (DM), Evers method was used to determine the total starch content of tubers, the polarimetric method and a glucometer test were used to determine reducing sugars, glycoalkaloids and inorganic phosphorus were determined by spectrophotometric method. There have been selected 5 hybrids suitable for industrial processing and as a source material for breeding. One potato hybrid with 25,06 % content of DM, more than 18,22 % of starch met the requirements for potatoes used for processing into starch and starch products; another potato hybrid can be recommended for the production of fried potato products according to the parameters: DM – 22.40 % starch – 16.18 %, reducing sugars – 0.23 %, glycoalkaloids – 62,0 mg/kg. Three of the studied hybrids with the content of DM of more than 22 %, starch not less than 16%, reducing sugars 0.2-0.4 % and glycoalkaloids 60-126 mg / kg may be used for the production of other types of potato products. The rest of the hybrids can only be recommended for use as table potatoes. The relationship between indicators affecting the quality of potato products has been revealed. Correlations were established between the mass fractions of: dry matter and starch in the tuber (r = 0.98) – high correlation; reducing sugars and glycoalkaloids (r = 0.68); tuber dry matter and glycoalkaloids (r = 0.59); dry matter and glucose (r = -0.61); starch and glucose (r = -0.58) – average correlations. It has been established that the mass fraction of reducing sugars and the direction of rotation of the plane of polarization of light by sugars change non-linearly under different temperature conditions of sample storage.
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There has been increasing consumption of potato products such as French fries and crisps in most countries as a result of lifestyle change in both developed and developing countries. Due to their generally pleasurable taste and texture, they are appreciated by a high number of consumers across the world, with the younger members of the population mostly those in the urban areas having a higher preference. The hard economic situations have also driven many people to their consumption as they are affordable. Moreover, these products are convenient for the younger generation who do not prepare their own food. However, there have been food safety concerns that have been linked in the past to glycoalkaloids in the raw potatoes that are used for processing. Potatoes are known to accumulate glycoalkaloids (GAs) during growth and postharvest storage. Some potato varieties have been shown to have high glycoalkaloids. These toxicants have been found to bioaccumulate in the body especially if daily consumption of foods containing the glycoalkaloids are consumed. Glycoalkaloids lead to intestinal discomfort, vomiting, fever, diarrhea and neurological problems and can lead to human or animal deaths in cases of acute toxicity. Transportation, handling, poor storage and exposure to sunlight during marketing of potatoes exposes consumers to potential risk of glycoalkaloids due to injury and greening which lead to increased levels of glycoalkaloids. Glycoalkaloids are quite stable and therefore, freeze-drying, boiling, dehydration or microwaving have got limited effect and thus persist through the processing conditions into the final products with the levels being proportional to the concentrations in the raw materials used. This current review focuses on the occurrence of glycoalkakloids in potato and potato products that are commonly consumed.
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The important glycoalkaloids in potatoes are α-solanine and α-chaconine. Their natural function is probably to serve as stress metabolites or phytoalexins for the protection of the potato when attacked by insects, fungi, etc. They contribute flavor to potatoes but at higher concentrations cause bitterness and are toxic to humans. α-Solanine and α-chaconine appear to have two main toxic actions, one on cell membranes and another one on acetylcholinesterase. Symptoms of α-solanine/α-chaconine poisoning involve an acute gastrointestinal upset with diarrhea, vomiting and severe abdominal pain. An instrumental high-performance thin-layer chromatography (HPTLC) method was applied for the quantification of α-solanine and α-chaconine in peeled potato skin, raw potato pulp and cooked peeled potato tubers. The limit of quantification (LOQ) for α-solanine and α-chaconine was found 5.0 mg kg-1 of each glycoalkaloid. In this study were examined the factors of potential loss of α-solanine and α-chaconine in potato tubers during peeling (factor=0.8) and cooking into edible stage in salted water (factor=0.8). The combined loss factor of peeling and cooking for sum of both glycoalkaloids in potato tubers was 0.64. These factors were practically used for the probabilistic exposure assessment of the intake of potato glycoalkaloids in the Czech Republic.
Potatoes (Solanum tuberosum) are an important global crop that can be transformed into many products impacting several health dimensions ranging from under-nutrition, food security and disease prevention to issues of over-nutrition including obesity, diabetes, heart disease. Processed potato products are typically categorized as high fat and sodium foods, as well as being classified as a significant source of carbohydrate, in the form of starch. Conversely, potato products are less known for their contribution of key micronutrients (vitamin C, potassium, magnesium), fiber, and phytochemicals (phenolics and carotenoids). More recent insight into the nutritional value of potatoes and the potential of potato phytochemicals to modulate oxidative and inflammatory stress as well as the potential to alter glycemic response has resulted in increased interest in strategies to improve and leverage the nutritional quality of processed potatoes. This review summarizes critical information on nutritional profiles of potatoes and their processed products and describes the state of the science relative to the influence of in-home and common commercial processing on nutritional quality and potential impacts on human health.
The aim of this study was to determine the effects of the different stages of industrial processing of potatoes, on the content of glycoalkaloids (chaconine and solanine) and nitrates in the raw material, intermediates, finished granules and waste products.The material used for the study included samples of raw tubers, semi-finished products and finished products taken directly from 8 points in the technological line for the production of potato granules, and 3 points from the waste product line. The samples were collected three times within two years of research (in 2009 and 2010) from the following places: 1/unpeeled potato, 2/potato after peeling, 3/potato after blanching, 4/potato after cooling, 5/steamed potato, 6/pneumatically dried potato, 7/product after fluidization drying, 8/granulated product, and waste products: 9/peels, 10/waste after air drying and 11/after fluidization drying.In the raw material, intermediates, finished granules and waste products, the concentrations of glycoalkaloids (α-chaconine and α-solanine) were determined using an HPLC method, and nitrates were determined colorimetrically using an RQflex analyser.It was found that the industrial processes of potato granules significantly decreased the concentration of glycoalkaloids (chaconine and solanine) and nitrates in intermediates and finished products when compared to raw material. The highest decrease in glycoalkaloids was caused by peeling (50%) and blanching (63%). The concentration of nitrates decreased the most after thermal processes – after blanching a decrease of 20% and after air drying – by 50%. The dehydrated potato granules contained on average 14% of the initial quantity of glycoalkaloids and 48% of nitrates. High content of toxic compounds was found in potato peels but dry wastes after pneumatic drying or after fluidization contained proportionally low contents of those compounds.
This study was to determine both the contents of chlorophyll (Chl) and potato glycoalkaloids (PGA) in which the cortex tissues (the outer 1-3mm thick), prepared from‘May Queen’ potatoes, were stored at 1°, 5°, 10° and 15°C under white fluorescent light (5, 200-5, 800 lx) or in the dark. Further, the effects of light exposure on changes ofChland PGA contents in the cortex and the pith tissues of potato tubers coated half with aluminum foil were also examined.1. The cortex tissues stored at 1°and 5°C under light exposure showed no color change and both of theChland PGA contents showed no change throughout the storage period. At 10°C-storage, they turned green from the 4th day accompanied by increases in theChland PGA content. On the other hand, the samples stored at 15°C turned green from the 2nd day. As the storage period was prolonged, the green color of this sample became deeper and the Chl content increased. The PGA content also increased with an increase of theChlcontent. It was found that the light exposure would accelerate the content of α-chaconine and α-solanine and that the increase of the latter compound was particularly remarkable.2. A lengthwise half of potato tubers was coated with aluminum foil and subjected to light exposure at 15°C for 7 days. TheChlcontent in the cortex tissues of the coated half was fairly higher than that stored in the dark, but it was lower than that of the lightened one. On the other hand, the PGA content in the cortex tissues of the coated half was lower than that of the lightened half, and it was almost the same amount as that stored in the dark.3. It is desirable to store potato tubers at a temperature of 10°C or below while insulating light as strictly as possible.
Potatoes, members of the Solanaceae plant family, serve as a major, inexpensive food source for both energy (starch) and good-quality protein, with worldwide production of about 350 million tons per year. U.S. per capita consumption of potatoes is about 61 kg/year. Potatoes also produce potentially toxic glycoalkaloids, both during growth and after harvest. Glycoalkaloids appear to be more toxic to man than to other animals. The toxicity may be due to anticholinesterase activity of the glycoalkaloids on the central nervous system and to disruptions of cell membranes affecting the digestive system and other organs. The possible contribution of glycoalkaloids to the multifactorial aspects of teratogenicity is inconclusive. Possible safe levels are controversial; guidelines limiting glycoalkaloid content of potato cultivars are currently being debated. This review presents an integrated, critical assessment of the multifaceted aspects of the role glycoalkaloids play in nutrition and food safety; chemistry and analysis; plant physiology, including biosynthesis, distribution, inheritance, host-plant resistance, and molecular biology; preharvest conditions such as soil composition and climate; and postharvest events such as effects of light, temperature, storage time, humidity, mechanical injury, sprouting inhibition, and processing. Further research needs are suggested for each of these categories in order to minimize pre- and postharvest glycoalkaloid synthesis. The overlapping aspects are discussed in terms of general concepts for a better understanding of the impact of glycoalkaloids in plants and in the human diet. Such an understanding can lead to the development of potato varieties with a low content of undesirable compounds and will further promote the utilization of potatoes as a premier food source for animals and humans.