Potato Glycoalkaloids Research Articles

High-Performance Liquid Chromatographic Determination of the Metabolites of the Potato Glycoalkaloids, α-Chaconine and α-Solanine, in Potato Tubers and Potato Products

Abstract A high-performance liquid chromatographic method has been developed to separate and quantify the metabolites, γ-chaconine, β1-and β2-chaconine, γ-solanine and β2-solanine, of the potato gly-coalkaloids α-chaconine and α-solanine in potatoes and potato products. A carbohydrate analysis column and a solvent system of tetrahydrofuran-water-acetonitrile (55:8:37) were employed for the separation. Flow rate was 1.1 ml/min and the compounds were monitored at 215 nm. β2-chaconine (0.63 mg to 29.75 mg/100 g dried weight) was present in all samples whereas the other glycosides of α-chaconine were only detectable in the animal feed products. It appears that some of the animal feeds may contain trace amounts of γ-solanine and an unknown which maybe β1-solanine. Limit of detection for all glycosides was 0.05 μg/μl. Elution time for all the lower glycosides of α-chaconine was 8 min versus 16 min for the α-solanine group. These metabolic compounds were confirmed using thin-layer chromatography.

A Composite Reference Standard for the Identification of Potato Glycoalkaloids

A Composite Reference Standard for the Identification of Potato Glycoalkaloids

Semi-Preparative High-Performance Liquid Chromatographic Separation of Potato Glycoalkaloids

Abstract A semi-preparative high-performance liquid chromatographic method has been developed to separate crude mixtures of the potato glycoalkaloids α-chaconine, α-solanine, commersonine and demissine. Milligram quantities of each substance can be obtained within an 8 hour period. A Zorbax semi-preparative NH2 column and a solvent system of tetrahydrofuran-water-acetonitrile (55:20:25) were employed for the separation. The flow rate was 1.0 ml/min. Glycoalkaloid separations were monitored using both refractive index and ultraviolet detection (215 nm). Further analyses of these glycoalkaloids were done using analytical high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) to check compound purity and identity.

Transformations of potato glycoalkaloids by rumen microorganisms.

Transformations of potato glycoalkaloids by rumen microorganisms.

On the colour reactions of potato glycoalkaloids in strong acids in the presence of paraformaldehyde

The colour reaction of potato glycoalkaloids, containing solanidine as steroid, with strong acids and paraformaldehyde was examined to elucidate the kinetics and mutual relationship of the ‘Clarke’ and ‘Marquis’ reactions. It was found that the influence of time of addition of paraformaldehyde was the major factor in deciding the type of colour changes encountered. This factor and the specific absorption kinetics have important consequences for the use of these types of colour reactions as a quantitative assay. According to the structural similarity of the steroidal part of potato glycoalkaloids and cholesterol, colour reactions of both have been compared, indicating that both steroids react in strong acids in the presence of an oxidator, provided that the more lipophilic character of cholesterol is taken into account. Therefore a similar mechanism of a serial oxidation of carbonium ions as in the case of cholesterol, is suggested as the basis for these specific colour reactions of potato glycoalkaloids.

Analysis of Potato Glycoalkaloids by Gas-Liquid Chromatography of Alkaloid Components

A gas-liquid chromatographic (GLC) method has been developed for the analysis of potato glycoalkaloids by direct determination of the alkaloid components isolated by hydrolysis with 1N ethanolic HCl. Recoveries of solanidine from potato tubers and foliage fortified with solanine over a range approximately 0.5 to 5 times the glycoalkaloid originally present averaged greater than 95%, and the lower limit of sensitivity was 0.25 mg/100 g using a nitrogen--phosphorus detector. A means of distinguishing solanidine and demissidine by formation of their respective 3 beta-trifluoroacetates with trifluoroacetic anhydride (TFAA) is demonstrated.

Total glycoalkaloids in potatoes and potato chips.

Total glycoalkaloids in potatoes and potato chips.

The mass extraction of potato glycoalkaloids from blossoms

A new procedure has been developed to extract gram quantities of glycoalkaloids from freeze-dried potato blossoms. The per cent recovery is 65–70%, yielding a mixed glycoalkaloid product that is greater than 90% glycoalkaloids. This method is very simple and rapid with completion in only two days. This new methodology will be very useful in entomological and toxicological research where large amounts of these glycoalkaloids are utilized.

A rapid quantitative assay for solanidine glycoalkaloids in potatoes and industrial potato protein

Aprapid quantitative assay for potato glycoalkaloids with solanidine (solanid-5en-3β-ol) as steriodal aglycone is described. The method of Sachse & Bachmann has been modified with respect to the extraction and working up procedures to increase the speed ans ease of analysis. A considerable simplification of analysis was achieved by replacing the original ether extraction and celite filtration by centrifugation. Fresh potato and industrial potato protein were analysed with this method. Industrial potato protein from several sources contained widely divergent glycoalkaloid contents (5–165 mg/100 g).

A Sterol-binding assay for potato glycoalkaloids

A method is described for quantitative analysis of potato glycoalkaloids based on their ability to complex with free sterols in alcoholic solution, the amount of unbound sterol being inversely proportional to the amount of alkaloid present. Since the alkaloid-sterol complex is soluble, unbound sterol is estimated by GLC.

High-performance liquid chromatographic separation of potato glycoalkaloids

Separations of three glycoalkaloids ( a-chaconine, β-chaconine, and a-solanine) have been achieved by using three different columns: μBondapak C 18, μBondapak NH 2, and a carbohydrate analysis column. These methods have been employed to examine the purity of the potato glycoalkaloids isolated by thin-layer and column chromatographic separations. Also, samples of tubers, peels, blossoms, and sprouts have been analyzed to determine their content of a-chaconine, β-chaconine, and a-solanine by using the carbohydrate and μBondapak NH 2 columns.

Potato Glycoalkaloids: Effect on Survival and Feeding Behavior of the Potato Leafhopper12

Total glycoalkaloid (TGA) fractions, extracted from foliage of 10 differentially-resistant Solanum species, were fed to nymphs of Empoasca fabae (Harris) at concentrations equivalent to those of fresh foliage. The effects of TGA extracts on nymphal survival and on feeding behavior were assessed. Specific components of the feeding process were identified by use of an electronic recording system. Mean nymphal survival hours and salivation-ingestion periods ranged from a low of 2.7 h and 5.3 min, respectively, on extracts of S. hougasii Corr. foliage to a high of 47.7 h and 18.1 min, respectively, on extracts from S. bulbocastanum Dun., corresponding to a 38-fold difference in TGA concentration. Nymphal survival and duration of settling, salivation-ingestion, and nonfeeding were significantly correlated with TGA concentration (r = −0.86, −0.79, −0.93, and 0.82). Although these findings provide further evidence of a causal role for potato glycoalkaloids in leafhopper resistance, TGA extracts from 2 species, S. berthaultii (PI 218215) and S. chacoense (WRF 888), were considerably less limiting to survival than expected on the basis of concentration alone. These discrepancies may be due to differences in levels of individual glycoalkaloids. The specific glycoalkaloid, tomatine, e.g., significantly limited the duration of salivation-ingestion at concentrations as low as 0.05%. Levels, types, and biological activity of individual glycoalkaloids in Solanum species need to be characterized before the full significance of these steroidal glycosides in leafhopper resistance can be understood.

A new procedure for the mass extraction and collection of potato glycoalkaloids

A methodology for the collection of large volumes of potato glycoalkaloids from potato blossoms has been developed for use in preparative work. This new modification shortens and simplifies the laborious proceduresutilized heretofore and should prove a valuable aid for those requiring multiple gram quantities of pure glycoalkaloids for use in further research.

EVALUATION OF INJURED COMMERCIAL POTATO SAMPLES FOR TOTAL GLYCOALKALOID CONTENT

ABSTRACTStress by physical damage is one of the most significant factors which may cause an increase in potato glycoalkaloids. A high percentage of potatoes available on the retail market are physically damaged and possibly are subject to an internal build‐up of glycoalkaloids. To investigate this possibility, analyses for total glycoalkaloids were carried out on damaged potatoes purchased on the retail market. Four separate purchases of three different potato varieties were tested. From this limited sampling it cannot be concluded that no tubers containing a high level of glycoalkaloids due to physical stress reach the retail market. However, in the cross section of damaged potatoes analyzed, in no case was a dangerous level of glycoalkaloids observed.

Modifications of the comprehensive method for total glycoalkaloid determination

Continuing investigations and queries from workers in the field of potato research have led to minor modifications of the method for the determination of total potato glycoalkaloids (TGA) by Fitzpatrick and Osman (1). These small changes shorten the time for analysis and can possibly give improved recovery of TGA.

Potato glycoalkaloids: Increases and variations of ratios in aged slices over prolonged storage

Four commercial cultivars of potatoes were maintained under normal storage conditions at 44 F for 34 weeks. Except for a final 10 week interval tubers were withdrawn at 6 week intervals. After slicing, a portion of the slices was immediately analyzed for total glycoalkaloid content. The remaining slices were aged for four days in the dark at room temperature, then similarly analyzed.

Separation of potato glycoalkaloids by gas chromatography.

Separation of potato glycoalkaloids by gas chromatography.

Effects of N6-benzyladenine on glycoalkaloids in potatoes as determined by thin layer chromatography

Behandlung der Sprossknollen mit Benzyladenin fordert die Glykoalkaloidbildung der Solanaceen. Je nach Extraktionsmethode konnen unidentifizierte Alkaloide nachgewiesen werden.

The Relationship Between Glycoalkaloids and Disease Resistance in Potatoes

The Relationship Between Glycoalkaloids and Disease Resistance in Potatoes

A comprehensive method for the determination of total potato glycoalkaloids

A method has been developed for the quantitative analysis of total glycoalkaloids (TGA) in potato tubers. The method consists of TGA extraction by suitable solvent mixtures followed by hydrolysis of the glycosides and extraction of the aglycones. The aglycones are then quantitated by nonaqueous titration. The advantages of this method over those previously described are the inclusion of glycoalkaloids that are not measured by other methods, and the simplicity, safety, and rapid nature of the procedure. This method has been applied to the TGA analysis of potato tubers subjected to a variety of storage and treatment conditions.