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Folke Sitbon - One of the best experts on this subject based on the ideXlab platform.
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glycoalkaloid and calystegine levels in table potato cultivars subjected to wounding light and heat treatments
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Erik Petersson, Usman Arif, Hans Christer Andersson, Lisbeth Jonsson, Vera Schulzova, Veronika Krtkova, Jana Hajslova, Johan Meijer, Folke SitbonAbstract:Potato tubers naturally contain a number of defense substances, some of which are of major concern for food safety. Among these substances are the Glycoalkaloids and calystegines. We have here analyzed levels of Glycoalkaloids (α-chaconine and α-solanine) and calystegines (A3, B2, and B4) in potato tubers subjected to mechanical wounding, light exposure, or elevated temperature: stress treatments that are known or anticipated to induce glycoalkaloid levels. Basal glycoalkaloid levels in tubers varied between potato cultivars. Wounding and light exposure, but not heat, increased tuber glycoalkaloid levels, and the relative response differed among the cultivars. Also, calystegine levels varied between cultivars, with calystegine B4 showing the most marked variation. However, the total calystegine level was not affected by wounding or light exposure. The results demonstrate a strong variation among potato cultivars with regard to postharvest glycoalkaloid increases, and they suggest that the biosynthesis of ...
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Glycoalkaloid and Calystegine Levels in Table Potato Cultivars Subjected to Wounding, Light, and Heat Treatments
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Erik Petersson, Usman Arif, Hans Christer Andersson, Lisbeth Jonsson, Vera Schulzova, Veronika Krtkova, Jana Hajslova, Johan Meijer, Folke SitbonAbstract:Potato tubers naturally contain a number of defense substances, some of which are of major concern for food safety. Among these substances are the Glycoalkaloids and calystegines. We have here analyzed levels of Glycoalkaloids (α-chaconine and α-solanine) and calystegines (A₃, B₂, and B₄) in potato tubers subjected to mechanical wounding, light exposure, or elevated temperature: stress treatments that are known or anticipated to induce glycoalkaloid levels. Basal glycoalkaloid levels in tubers varied between potato cultivars. Wounding and light exposure, but not heat, increased tuber glycoalkaloid levels, and the relative response differed among the cultivars. Also, calystegine levels varied between cultivars, with calystegine B4 showing the most marked variation. However, the total calystegine level was not affected by wounding or light exposure. The results demonstrate a strong variation among potato cultivars with regard to postharvest glycoalkaloid increases, and they suggest that the biosynthesis of Glycoalkaloids and calystegines occurs independently of each other.
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reduction of cholesterol and glycoalkaloid levels in transgenic potato plants by overexpression of a type 1 sterol methyltransferase cdna
Plant Physiology, 2003Co-Authors: Lisa Arnqvist, Lisbeth Jonsson, P C Dutta, Folke SitbonAbstract:Transgenic potato (Solanum tuberosum cv Desiree) plants overexpressing a soybean (Glycine max) type 1 sterol methyltransferase (GmSMT1) cDNA were generated and used to study sterol biosynthesis in relation to the production of toxic Glycoalkaloids. Transgenic plants displayed an increased total sterol level in both leaves and tubers, mainly due to increased levels of the 24-ethyl sterols isofucosterol and sitosterol. The higher total sterol level was due to increases in both free and esterified sterols. However, the level of free cholesterol, a nonalkylated sterol, was decreased. Associated with this was a decreased glycoalkaloid level in leaves and tubers, down to 41% and 63% of wild-type levels, respectively. The results show that glycoalkaloid biosynthesis can be down-regulated in transgenic potato plants by reducing the content of free nonalkylated sterols, and they support the view of cholesterol as a precursor in glycoalkaloid biosynthesis.
Mendel Friedman - One of the best experts on this subject based on the ideXlab platform.
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glycoalkaloid content of some superior potato solanum tuberosum l clones and commercial cultivars
Archives of Phytopathology and Plant Protection, 2009Co-Authors: G K Kirui, R Elbedewy, O. Modesto Olanya, A. K. Misra, Mendel Friedman, P T EwellAbstract:Abstract Glycoalkaloids are important metabolites in potato because of their toxic properties and potential harmful effects to humans. To validate a rapid assay to determine and quantify glycoalkaloid content and its distribution in potato tubers, we have characterized and quantified, by HPLC and by colorimetry with bromphenol blue, the Glycoalkaloids in 15 potato cultivars and experimental clones grown in the tropical climate of Kenya. There was significant correlation of TGA by HPLC and colorimetry. Significant differences in glycoalkaloid content were detected among potato cultivars. The concentration of α-chaconine in the 15 cultivars ranged from 1.62 to 4.46 mg/100 g fresh weight (fwt), of α-solanine from 1.45 to 4.51 mg/100 g, and of solanidine from 1.58 to 5.21 mg/100 g. Total glycoalkaloid values (TGA, sum of the three compounds) for the 15 cultivars determined by HPLC ranged from 5.31 to 15.39 mg/100 g and the corresponding values determined by bromphenol blue colorimetry, from 3.51 to 17.48 mg/1...
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distribution of Glycoalkaloids in potato tubers of 59 accessions of two wild and five cultivated solanum species
Journal of Agricultural and Food Chemistry, 2008Co-Authors: Nobuyuki Kozukue, Kyungsoon Yoon, Gwangin Byun, Shuji Misoo, Carol Levin, Mendel FriedmanAbstract:Steroidal Glycoalkaloids are naturally occurring, secondary plant metabolites that are found in foods, including potatoes and tomatoes. Their content in plants is controlled by both genetic and environmental factors. Glycoalkaloid profiles can be passed to progenies during breeding and hybridization of wild and cultivated potatoes designed to develop improved potatoes. The most common potato, Solanum tuberosum, contains primarily the Glycoalkaloids, alpha-solanine and alpha-chaconine. However, wild-type potatoes being used for breeding new varieties contain other, less common Glycoalkaloids. Because glycoalkaloid composition is a major criterion for the release of new potato cultivars, we used HPLC, TLC, GC, and GC/MS to determine their nature and content in several Solanum species widely used in potato breeding and hybridization programs. Solanum tuberosum, as well as S. andigena and S. stenotomum, contained alpha-solanine and alpha-chaconine. S. canasense was found to contain only dehydrocommersonine. S. acaule contained alpha-tomatine and demissine. S. juzepczukii and S. curtilobum contained demissine and two previously unidentified Glycoalkaloids. We characterized them as demissidine-glucose/rhamnose (1/1 ratio) and demissidine-galactose/glucose/rhamnose (1/1/1 ratio), tentatively named dihydro-beta(1)-chaconine and dihydrosolanine, respectively. We found extensive variability in the glycoalkaloid profiles in the tested potato varieties. The possible significance of these findings for plant breeding and food safety is discussed.
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Potato Glycoalkaloids and metabolites : Roles in the plant and in the diet
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Mendel FriedmanAbstract:Potatoes, members of the Solanaceae plant family, serve as major, inexpensive low-fat food sources providing energy (starch), high-quality protein, fiber, and vitamins. Potatoes also produce biologically active secondary metabolites, which may have both adverse and beneficial effects in the diet. These include Glycoalkaloids, calystegine alkaloids, protease inhibitors, lectins, phenolic compounds, and chlorophyll. Because Glycoalkaloids are reported to be involved in host-plant resistance and to have a variety of adverse as well as beneficial effects in cells, animals, and humans, a need exists to develop a clearer understanding of their roles both in the plant and in the diet. To contribute to this effort, this integrated review presents data on the (a) history of Glycoalkaloids; (b) glycoalkaloid content in different parts of the potato plant, in processed potato products, and in wild, transgenic, and organic potatoes; (c) biosynthesis, inheritance, plant molecular biology, and glycoalkaloid−plant phyto...
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Glycoalkaloids and metabolites inhibit the growth of human colon ht29 and liver hepg2 cancer cells
Journal of Agricultural and Food Chemistry, 2004Co-Authors: Kaprang Lee, Nobuyuki Kozukue, Jaesook Han, Joonhong Park, Eunyoung Chang, Eunjung Baek, Jongsun Chang, Mendel FriedmanAbstract:As part of an effort to improve plant-derived foods such as potatoes, eggplants, and tomatoes, the antiproliferative activities against human colon (HT29) and liver (HepG2) cancer cells of a series of structurally related individual compounds were examined using a microculture tetrazolium (MTT) assay. The objective was to assess the roles of the carbohydrate side chain and aglycon part of Solanum glycosides in influencing inhibitory activities of these compounds. Evaluations were carried out with four concentrations each (0.1, 1, 10, and 100 microg/mL) of the the potato trisaccharide Glycoalkaloids alpha-chaconine and alpha-solanine; the disaccharides beta(1)-chaconine, beta(2)-chaconine, and beta(2)-solanine; the monosaccharide gamma-chaconine and their common aglycon solanidine; the tetrasaccharide potato glycoalkaloid dehydrocommersonine; the potato aglycon demissidine; the tetrasaccharide tomato glycoalkaloid alpha-tomatine, the trisaccharide beta(1)-tomatine, the disaccharide gamma-tomatine, the monosaccharide delta-tomatine, and their common aglycon tomatidine; the eggplant Glycoalkaloids solamargine and solasonine and their common aglycon solasodine; and the nonsteroidal alkaloid jervine. All compounds were active in the assay, with the Glycoalkaloids being the most active and the hydrolysis products less so. The effectiveness against the liver cells was greater than against the colon cells. Potencies of alpha-tomatine and alpha-chaconine at a concentration of 1 microg/mL against the liver carcinoma cells were higher than those observed with the anticancer drugs doxorubicin and camptothecin. Because alpha-chaconine, alpha-solanine, and alpha-tomatine also inhibited normal human liver HeLa (Chang) cells, safety considerations should guide the use of these compounds as preventative or therapeutic treatments against carcinomas.
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the folic acid analogue methotrexate protects frog embryo cell membranes against damage by the potato glycoalkaloid α chaconine
Food and Chemical Toxicology, 2000Co-Authors: M L Mcwilliams, James T Blankemeyer, Mendel FriedmanAbstract:Abstract As part of an effort to improve the safety of plant foods, a need exists to more clearly delineate the mechanisms of toxicities of Glycoalkaloids, which may be present in Solanum plant species such as potatoes, tomatoes and eggplants. α-Chaconine is a major glycoalkaloid present in potatoes. To assess the possible influence of structure of pteridine derivatives on toxicity of potato Glycoalkaloids, a previous study that demonstrated the protective effects of folic acid against the Solanum glycoalkaloid α-chaconine-induced toxicity on Xenopus laevis frog embryo cell membranes was extended to two folate analogues—a synthetic compound widely used as a therapeutic agent methotrexate, and naturally occurring l -monapterin. Adverse effects on embryos were evaluated by observing changes in membrane potentials with an electrochromic dye, di-4-ANEPPS, as a fluorescent probe for the integrity of the membranes. Methotrexate decreased α-chaconine-induced polarization, as did folic acid. This decrease may result from an alteration of membrane conformations that prevents the binding of the glycoalkaloid to the membrane receptor sites, and/or from effects on folic acid metabolism. In contrast, l -monapterin did not significantly reduce the α-chaconine-induced toxicity. The possible significance of these results to food safety is discussed.
Lisbeth Jonsson - One of the best experts on this subject based on the ideXlab platform.
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glycoalkaloid and calystegine levels in table potato cultivars subjected to wounding light and heat treatments
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Erik Petersson, Usman Arif, Hans Christer Andersson, Lisbeth Jonsson, Vera Schulzova, Veronika Krtkova, Jana Hajslova, Johan Meijer, Folke SitbonAbstract:Potato tubers naturally contain a number of defense substances, some of which are of major concern for food safety. Among these substances are the Glycoalkaloids and calystegines. We have here analyzed levels of Glycoalkaloids (α-chaconine and α-solanine) and calystegines (A3, B2, and B4) in potato tubers subjected to mechanical wounding, light exposure, or elevated temperature: stress treatments that are known or anticipated to induce glycoalkaloid levels. Basal glycoalkaloid levels in tubers varied between potato cultivars. Wounding and light exposure, but not heat, increased tuber glycoalkaloid levels, and the relative response differed among the cultivars. Also, calystegine levels varied between cultivars, with calystegine B4 showing the most marked variation. However, the total calystegine level was not affected by wounding or light exposure. The results demonstrate a strong variation among potato cultivars with regard to postharvest glycoalkaloid increases, and they suggest that the biosynthesis of ...
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Glycoalkaloid and Calystegine Levels in Table Potato Cultivars Subjected to Wounding, Light, and Heat Treatments
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Erik Petersson, Usman Arif, Hans Christer Andersson, Lisbeth Jonsson, Vera Schulzova, Veronika Krtkova, Jana Hajslova, Johan Meijer, Folke SitbonAbstract:Potato tubers naturally contain a number of defense substances, some of which are of major concern for food safety. Among these substances are the Glycoalkaloids and calystegines. We have here analyzed levels of Glycoalkaloids (α-chaconine and α-solanine) and calystegines (A₃, B₂, and B₄) in potato tubers subjected to mechanical wounding, light exposure, or elevated temperature: stress treatments that are known or anticipated to induce glycoalkaloid levels. Basal glycoalkaloid levels in tubers varied between potato cultivars. Wounding and light exposure, but not heat, increased tuber glycoalkaloid levels, and the relative response differed among the cultivars. Also, calystegine levels varied between cultivars, with calystegine B4 showing the most marked variation. However, the total calystegine level was not affected by wounding or light exposure. The results demonstrate a strong variation among potato cultivars with regard to postharvest glycoalkaloid increases, and they suggest that the biosynthesis of Glycoalkaloids and calystegines occurs independently of each other.
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reduction of cholesterol and glycoalkaloid levels in transgenic potato plants by overexpression of a type 1 sterol methyltransferase cdna
Plant Physiology, 2003Co-Authors: Lisa Arnqvist, Lisbeth Jonsson, P C Dutta, Folke SitbonAbstract:Transgenic potato (Solanum tuberosum cv Desiree) plants overexpressing a soybean (Glycine max) type 1 sterol methyltransferase (GmSMT1) cDNA were generated and used to study sterol biosynthesis in relation to the production of toxic Glycoalkaloids. Transgenic plants displayed an increased total sterol level in both leaves and tubers, mainly due to increased levels of the 24-ethyl sterols isofucosterol and sitosterol. The higher total sterol level was due to increases in both free and esterified sterols. However, the level of free cholesterol, a nonalkylated sterol, was decreased. Associated with this was a decreased glycoalkaloid level in leaves and tubers, down to 41% and 63% of wild-type levels, respectively. The results show that glycoalkaloid biosynthesis can be down-regulated in transgenic potato plants by reducing the content of free nonalkylated sterols, and they support the view of cholesterol as a precursor in glycoalkaloid biosynthesis.
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Effects of ethephon and norbornadiene on sterol and glycoalkaloid biosynthesis in potato tuber discs
Physiologia Plantarum, 1993Co-Authors: Annika Bergenstrahle, Elisabeth Tillberg, Lisbeth JonssonAbstract:The accumulation of Glycoalkaloids that normally takes place in aerobically incubated potato (Solanum tuberosum L.) tuber discs has been found to be inhibited by the ethylene-releasing substance ethephon. Using ethephon and the ethylene action inhibitor norborna-2,5-diene, the effect of ethylene on the synthesis of sterols and Glycoalkaloids, which partly share their biosynthetic pathway, was investigated. Control discs showed incorporation of (2-14C)mevalonic acid into free sterols, steryl esters, steryl glycosides and acylated steryl glycosides at 24 h, thereafter the radioactivity decreased in free sterols and steryl esters concomitant with the appearance of radioactivity in Glycoalkaloids. Discs with ethephon additions contained more radioactivity in all sterol classes at all time-points, but no Glycoalkaloids were formed. The enzyme S-adenosyl-l-methionine:sterol C24 methyltransferase (SMT, EC 2. 1. 1. 41), located at one presumed branching point in the sterol and glycoalkaloid pathway, was characterized and found to exhibit similar characteristics as in other plants, but a lower specific activity. The activity of SMT increased in ageing tuber discs and this increase was further stimulated by ethephon, but inhibited by norborna-2,5-diene. The activity of the glycoalkaloid-specific enzyme UDP-glucose:solanidine glucosyltransferase (EC 2. 4. 1) also increased after slicing, but here ethephon additions counteracted the induction. The activity of the sterol-specific UDP-glucose:sterol glucosyltransferase (EC 2. 4. 1) was unaffected by either tuber slicing or ethephon additions. The results indicate that ethylene stimulates sterol synthesis in wounded potato discs, and that the wound-induction of SMT is regulated by ethylene.
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Effects of ethephon and norbornadiene on sterol and glycoalkaloid biosynthesis in potato tuber discs
Physiologia Plantarum, 1993Co-Authors: Annika Bergenstrahle, Elisabeth Tillberg, Lisbeth JonssonAbstract:The accumulation of Glycoalkaloids that normally takes place in aerobically incubated potato (Solanum tuberosum L.) tuber discs has been found to be inhibited by the ethylene-releasing substance ethephon. Using ethephon and the ethylene action inhibitor norborna-2,5-diene, the effect of ethylene on the synthesis of sterols and Glycoalkaloids, which partly share their biosynthetic pathway, was investigated. Control discs showed incorporation of (2-14C)mevalonic acid into free sterols, steryl esters, steryl glycosides and acylated steryl glycosides at 24 h, thereafter the radioactivity decreased in free sterols and steryl esters concomitant with the appearance of radioactivity in Glycoalkaloids. Discs with ethephon additions contained more radioactivity in all sterol classes at all time-points, but no Glycoalkaloids were formed. The enzyme S-adenosyl-l-methionine:sterol C24 methyltransferase (SMT, EC 2. 1. 1. 41), located at one presumed branching point in the sterol and glycoalkaloid pathway, was characterized and found to exhibit similar characteristics as in other plants, but a lower specific activity. The activity of SMT increased in ageing tuber discs and this increase was further stimulated by ethephon, but inhibited by norborna-2,5-diene. The activity of the glycoalkaloid-specific enzyme UDP-glucose:solanidine glucosyltransferase (EC 2. 4. 1) also increased after slicing, but here ethephon additions counteracted the induction. The activity of the sterol-specific UDP-glucose:sterol glucosyltransferase (EC 2. 4. 1) was unaffected by either tuber slicing or ethephon additions. The results indicate that ethylene stimulates sterol synthesis in wounded potato discs, and that the wound-induction of SMT is regulated by ethylene.
M. Finlay B. Dale - One of the best experts on this subject based on the ideXlab platform.
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Effect of light exposure on the glycoalkaloid content of Solanum phureja tubers.
Journal of Agricultural and Food Chemistry, 2001Co-Authors: D. Wynne Griffiths, M. Finlay B. DaleAbstract:The individual glycoalkaloid contents of tubers from eleven Solanum phureja genotypes have been determined prior to and following exposure to light. In all genotypes, light exposure resulted in a statistically significant increase in total glycoalkaloid content. In nine of the genotypes studied, this was not only due to an increase in the levels of the solanidine-based Glycoalkaloids, α-solanine and α-chaconine, but also due to the light-induced synthesis of a tomatidenol-based glycoalkaloid, α-solamarine. Those genotypes that accumulated α-solamarine in their tubers also contained tomatidenol-based Glycoalkaloids in their leaves, but only solanidine-based Glycoalkaloids were detected in the sprouts. Keywords: Glycoalkaloids; α-solanine; α-chaconine; α-solamarine; light; tubers; leaves; sprouts
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Photo-induced synthesis of tomatidenol-based Glycoalkaloids in Solanum phureja tubers.
Phytochemistry, 2000Co-Authors: D. Wynne Griffiths, Henry Bain, G. W. Robertson, Nigel Deighton, M. Finlay B. DaleAbstract:Abstract The effect of light exposure on the steroidal glycoalkaloid content of Solanum phureja tubers has been investigated and compared with that in domesticated potato ( Solanum tuberosum ) tubers. The results indicated that the increase in the concentration of solanidine-based Glycoalkaloids, ᾱ-solanine and ᾱ-chaconine was broadly similar in both species. However, in the S. phureja tubers, light exposure also induced the synthesis of tomatidenol-based Glycoalkaloids. These have been identified as α- and β-solamarine. These Glycoalkaloids were not detected in tubers continually stored in darkness.
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glycoalkaloid increase in solarium tuberosum on exposure to light
Annals of Applied Biology, 1993Co-Authors: M. Finlay B. Dale, Henry Bain, D. Wynne Griffiths, D. ToddAbstract:Summary Tubers of six commercially available potato cultivars were placed in bright light (140 jUmol“1 m”2), approximately equivalent to dull daylight, for a continuous period of up to seven days. The tubers were sampled at intervals, scored for degree of greening, freeze-dried and subsequently assessed for glycoalkaloid and chlorophyll content. There were significant differences between the cultivars in their rates of greening and increase in glycoalkaloid content. There was an apparent relationship between the two characters. Increases in the individual Glycoalkaloids a–chaconine and a-solanine were also assessed. The results are discussed in terms of the implications for the potato industry.
Erik Petersson - One of the best experts on this subject based on the ideXlab platform.
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glycoalkaloid and calystegine levels in table potato cultivars subjected to wounding light and heat treatments
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Erik Petersson, Usman Arif, Hans Christer Andersson, Lisbeth Jonsson, Vera Schulzova, Veronika Krtkova, Jana Hajslova, Johan Meijer, Folke SitbonAbstract:Potato tubers naturally contain a number of defense substances, some of which are of major concern for food safety. Among these substances are the Glycoalkaloids and calystegines. We have here analyzed levels of Glycoalkaloids (α-chaconine and α-solanine) and calystegines (A3, B2, and B4) in potato tubers subjected to mechanical wounding, light exposure, or elevated temperature: stress treatments that are known or anticipated to induce glycoalkaloid levels. Basal glycoalkaloid levels in tubers varied between potato cultivars. Wounding and light exposure, but not heat, increased tuber glycoalkaloid levels, and the relative response differed among the cultivars. Also, calystegine levels varied between cultivars, with calystegine B4 showing the most marked variation. However, the total calystegine level was not affected by wounding or light exposure. The results demonstrate a strong variation among potato cultivars with regard to postharvest glycoalkaloid increases, and they suggest that the biosynthesis of ...
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Glycoalkaloid and Calystegine Levels in Table Potato Cultivars Subjected to Wounding, Light, and Heat Treatments
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Erik Petersson, Usman Arif, Hans Christer Andersson, Lisbeth Jonsson, Vera Schulzova, Veronika Krtkova, Jana Hajslova, Johan Meijer, Folke SitbonAbstract:Potato tubers naturally contain a number of defense substances, some of which are of major concern for food safety. Among these substances are the Glycoalkaloids and calystegines. We have here analyzed levels of Glycoalkaloids (α-chaconine and α-solanine) and calystegines (A₃, B₂, and B₄) in potato tubers subjected to mechanical wounding, light exposure, or elevated temperature: stress treatments that are known or anticipated to induce glycoalkaloid levels. Basal glycoalkaloid levels in tubers varied between potato cultivars. Wounding and light exposure, but not heat, increased tuber glycoalkaloid levels, and the relative response differed among the cultivars. Also, calystegine levels varied between cultivars, with calystegine B4 showing the most marked variation. However, the total calystegine level was not affected by wounding or light exposure. The results demonstrate a strong variation among potato cultivars with regard to postharvest glycoalkaloid increases, and they suggest that the biosynthesis of Glycoalkaloids and calystegines occurs independently of each other.