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1.
Pharm Biol ; 60(1): 1317-1330, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35811507

RESUMO

CONTEXT: Solanaceae glycoalkaloids (SGAs) possess cardiomodulatory activity. OBJECTIVE: This study investigated the potential interaction between verapamil and glycoalkaloids. MATERIAL AND METHODS: The cardioactivity of verapamil and glycoalkaloids (α-solanine and α-chaconine) was tested in adult beetle (Tenebrio molitor) myocardium in vitro using microdensitometric methods. The myocardium was treated with pure substances and mixtures of verapamil and glycoalkaloids for 9 min with saline as a control. Two experimental variants were used: simultaneous application of verapamil and glycoalkaloids or preincubation of the myocardium with one of the compounds followed by perfusion with a verapamil solution. We used 9 × 10-6-5 × 10-5 M and 10-9-10-5 M concentration for verapamil and glycoalkaloids, respectively. RESULTS: Verapamil, α-solanine and α-chaconine showed cardioinhibitory activity with IC50 values equal to 1.69 × 10-5, 1.88 × 10-7 and 7.48 × 10-7 M, respectively. When the glycoalkaloids were applied simultaneously with verapamil, an antagonistic effect was observed with a decrease in the maximal inhibitory effect and prolongation of t50 and the recovery time characteristic of verapamil. We also confirmed the expression of two transcript forms of the gene that encodes the α1 subunit of L-type calcium channels in the myocardium and brain with equal transcription levels of both forms in the myocardium and significant domination of the shorter form in the brain of the insect species tested. DISCUSSION AND CONCLUSIONS: The results show that attention to the composition of the daily diet during therapy with various drugs is particularly important. In subsequent studies, the nature of interaction between verapamil and SGAs on the molecular level should be checked, and whether this interaction decreases the efficiency of cardiovascular therapy with verapamil in humans.


Assuntos
Solanaceae , Solanina , Solanum tuberosum , Solanina/análogos & derivados , Solanina/farmacologia , Verapamil/farmacologia
2.
Sci Rep ; 11(1): 20029, 2021 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-34625595

RESUMO

Inhibiting sprouting of potatoes is an interesting subject needed for potato storage and industry. Sprouting degrades the quality of tuber along with releasing α-solanine and α-chaconine, which are harmful for health. Sprout suppressants, available in the market, are either costly or toxic to both health and environment. So, there is a need for developing countries to explore new sprouting suppressant compound which is cheap, non-toxic and reasonably efficient in comparison to commercial ones. We have established that simple maleic acid and L-tartaric acid are effective sprout suppressing agents. Both can hinder sprouting up to 6 weeks and 4 weeks post treatment respectively at room temperature in dark. These do not affect the quality parameters, retain the moisture content and maintain the stout appearance of the tubers along the total storage period. Thus maleic acid and L-tartaric acid would qualify as alternative, cheap, efficient sprout suppressant for potato storage and processing.


Assuntos
Armazenamento de Alimentos/métodos , Maleatos/farmacologia , Tubérculos/crescimento & desenvolvimento , Solanina/análogos & derivados , Solanum tuberosum/crescimento & desenvolvimento , Tartaratos/farmacologia , Tubérculos/efeitos dos fármacos , Tubérculos/metabolismo , Solanina/metabolismo , Solanum tuberosum/efeitos dos fármacos , Solanum tuberosum/metabolismo
3.
Plant J ; 108(1): 81-92, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34273198

RESUMO

Steroidal glycoalkaloids (SGAs) are toxic specialized metabolites found in members of the Solanaceae, such as Solanum tuberosum (potato) and Solanum lycopersicum (tomato). The major potato SGAs are α-solanine and α-chaconine, which are biosynthesized from cholesterol. Previously, we have characterized two cytochrome P450 monooxygenases and a 2-oxoglutarate-dependent dioxygenase that function in hydroxylation at the C-22, C-26 and C-16α positions, but the aminotransferase responsible for the introduction of a nitrogen moiety into the steroidal skeleton remains uncharacterized. Here, we show that PGA4 encoding a putative γ-aminobutyrate aminotransferase is involved in SGA biosynthesis in potatoes. The PGA4 transcript was expressed at high levels in tuber sprouts, in which SGAs are abundant. Silencing the PGA4 gene decreased potato SGA levels and instead caused the accumulation of furostanol saponins. Analysis of the tomato PGA4 ortholog, GAME12, essentially provided the same results. Recombinant PGA4 protein exhibited catalysis of transamination at the C-26 position of 22-hydroxy-26-oxocholesterol using γ-aminobutyric acid as an amino donor. Solanum stipuloideum (PI 498120), a tuber-bearing wild potato species lacking SGA, was found to have a defective PGA4 gene expressing the truncated transcripts, and transformation of PI 498120 with functional PGA4 resulted in the complementation of SGA production. These findings indicate that PGA4 is a key enzyme for transamination in SGA biosynthesis. The disruption of PGA4 function by genome editing will be a viable approach for accumulating valuable steroidal saponins in SGA-free potatoes.


Assuntos
4-Aminobutirato Transaminase/metabolismo , Solanina/análogos & derivados , Solanum tuberosum/genética , 4-Aminobutirato Transaminase/genética , Edição de Genes , Hidroxilação , Cetocolesteróis/biossíntese , Cetocolesteróis/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Tubérculos/enzimologia , Tubérculos/genética , Tubérculos/fisiologia , Saponinas/biossíntese , Saponinas/química , Solanina/química , Solanina/metabolismo , Solanum tuberosum/enzimologia , Solanum tuberosum/fisiologia
4.
Nat Commun ; 12(1): 1300, 2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33637735

RESUMO

Potato (Solanum tuberosum), a worldwide major food crop, produces the toxic, bitter tasting solanidane glycoalkaloids α-solanine and α-chaconine. Controlling levels of glycoalkaloids is an important focus on potato breeding. Tomato (Solanum lycopersicum) contains a bitter spirosolane glycoalkaloid, α-tomatine. These glycoalkaloids are biosynthesized from cholesterol via a partly common pathway, although the mechanisms giving rise to the structural differences between solanidane and spirosolane remained elusive. Here we identify a 2-oxoglutarate dependent dioxygenase, designated as DPS (Dioxygenase for Potato Solanidane synthesis), that is a key enzyme for solanidane glycoalkaloid biosynthesis in potato. DPS catalyzes the ring-rearrangement from spirosolane to solanidane via C-16 hydroxylation. Evolutionary divergence of spirosolane-metabolizing dioxygenases contributes to the emergence of toxic solanidane glycoalkaloids in potato and the chemical diversity in Solanaceae.


Assuntos
Vias Biossintéticas , Dioxigenases/biossíntese , Dioxigenases/genética , Solanum tuberosum/enzimologia , Solanum tuberosum/genética , Sequência de Aminoácidos , Vias Biossintéticas/genética , Colesterol/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Hidroxilação , Ácidos Cetoglutáricos/metabolismo , Solanum lycopersicum/enzimologia , Solanum lycopersicum/genética , Filogenia , Plantas Geneticamente Modificadas , Metabolismo Secundário/genética , Metabolismo Secundário/fisiologia , Solanina/análogos & derivados , Solanum melongena/enzimologia , Solanum melongena/genética , Tomatina/análogos & derivados , Tomatina/metabolismo
5.
Chemosphere ; 258: 127254, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32559492

RESUMO

Glyphosate is the most used herbicide worldwide, targeting physiological pathways in plants. Recent studies have shown that glyphosate can also cause toxic effects in animals. We investigated the glyphosate-based herbicide (GBH)-induced changes in potato (Solanum tuberosum) plant chemistry and the effects of a GBH on the survival rate and oxidative status of the Colorado potato beetle (Leptinotarsa decemlineata). The beetles were reared on potato plants grown in pots containing soil treated with a GBH (Roundup Gold, 450 g/l) or untreated soil (water control). The 2nd instar larvae were introduced to the potato plants and then collected in 2 phases: as 4th instar larvae and as adults. The main glycoalkaloids of the potato plants, α-solanine and α-chaconine, were measured twice during the experiment. The α-solanine was reduced in potato plants grown in GBH-treated soil, which can be detrimental to plant defenses against herbivores. GBH treatment had no effect on the survival rate or body mass of the larvae or the adult beetles. In the larvae, total glutathione (tGSH) concentration and the enzyme activity of catalase (CAT), superoxide dismutase, and glutathione-S-transferase were increased in the GBH treatment group. In the adult beetles, CAT activity and tGSH levels were affected by the interactive effect of GBH treatment and the body mass. To conclude, environmentally relevant concentrations of a GBH can affect the potato plant's glycoalkaloid concentrations, but are not likely to directly affect the survival rate of the Colorado potato beetle, but instead, modify the antioxidant defense of the beetles via diet.


Assuntos
Besouros/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Solo/química , Solanum tuberosum/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Besouros/metabolismo , Glutationa Transferase/metabolismo , Glicina/toxicidade , Larva/efeitos dos fármacos , Larva/metabolismo , Oxirredução , Solanina/análogos & derivados , Solanina/metabolismo , Solanum tuberosum/crescimento & desenvolvimento , Solanum tuberosum/metabolismo
6.
J Agric Food Chem ; 68(5): 1390-1396, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31935098

RESUMO

Potato juice is a byproduct of starch processing currently used as feed. However, potato proteins are an untapped source of high-protein food for human nutrition if harmful constituents notably glycoalkaloids (GAs) are detoxified. The two principle GAs found in potato are α-chaconine and α-solanine, both consisting of a solanidine aglycone with a carbohydrate side chain. The first step in the detoxification of these compounds is the removal of the trisaccharide. Whole-genome sequencing of a bacterial isolate, Arthrobacter sp. S41, capable of completely degrading α-chaconine and α-solanine, revealed the presence of a gene cluster possibly involved in the deglycosylation of GAs. Functional characterization confirmed the enzymatic activity of the gene cluster involved in the complete deglycosylation of both α-chaconine and α-solanine. The novel enzymes described here may find value in the bioconversion of feed proteins to food proteins suitable for human nutrition.


Assuntos
Arthrobacter/metabolismo , Proteínas de Bactérias/metabolismo , Família Multigênica , Solanina/análogos & derivados , Solanum tuberosum/toxicidade , Arthrobacter/classificação , Arthrobacter/enzimologia , Arthrobacter/genética , Proteínas de Bactérias/genética , Biotransformação , Glicosilação , Filogenia , Solanina/química , Solanina/metabolismo , Solanina/toxicidade , Solanum tuberosum/metabolismo
7.
Genes (Basel) ; 10(11)2019 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-31718041

RESUMO

Steroidal glycoalkaloids (SGAs), which are widely produced by potato, even in other Solanaceae plants, are a class of potentially toxic compounds, but are beneficial to host resistance. However, changes of the other metabolic process along with SGA accumulation are still poorly understood and researched. Based on RNA sequencing (RNA-seq) and bioinformatics analysis, the global gene expression profiles of potato variety Helan 15 (Favorita) was investigated at four-time points during light exposure. The data was further verified by using quantitative Real-time PCR (qRT-PCR). When compared to the control group, 1288, 1592, 1737, and 1870 differentially expressed genes (DEGs) were detected at 6 h, 24 h, 48 h, and 8 d, respectively. The results of both RNAseq and qRT-PCR showed that SGA biosynthetic genes were up-regulated in the potato tuber under light exposure. Functional enrichment analysis revealed that genes related to PS light reaction and Protein degradation were significantly enriched in most time points of light exposure. Additionally, enriched Bins included Receptor kinases, Secondary metabolic process in flavonoids, Abiotic stress, and Biotic stress in the early stage of light exposure, but PS Calvin cycle, RNA regulation of transcription, and UDP glucosyl and glucoronyl transferases in the later stage. Most of the DEGs involved in PS light reaction and Abiotic stress were up-regulated at all four time points, whereas DEGs that participated in biotic stresses were mainly up-regulated at the later stage (48 h and 8 d). Cis-element prediction and co-expression assay were used to confirm the expressional correlation between genes that are responsible for SGA biosynthesis and disease resistance. In conclusion, the expressions of genes involved in PS light reaction, Abiotic stress, and Biotic stress were obviously aroused during the accumulation of SGAs induced by light exposure. Moreover, an increased defense response might contribute to the potato resistance to the infection by phytopathogenic microorganisms.


Assuntos
Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Solanina/análogos & derivados , Solanum tuberosum/fisiologia , Resistência à Doença/genética , Tubérculos/genética , Tubérculos/metabolismo , Tubérculos/efeitos da radiação , RNA-Seq , Metabolismo Secundário/genética , Solanina/metabolismo , Estresse Fisiológico/genética , Transcriptoma/efeitos da radiação , Sequenciamento do Exoma
8.
Pest Manag Sci ; 75(3): 793-800, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30136365

RESUMO

BACKGROUND: Potato (Solanum tuberosum) is the fourth culture in the world and is widely used in the agri-food industries. They generate by-products in which α-chaconine and α-solanine, the two major solanidine-based glycoalkaloids of potato, are present. As secondary metabolites, they play an important role in the protection system of potato and are involved in plant protection against insects. To add value to these by-products, we described here new glycoalkaloids that could have phytosanitary properties. RESULTS: Solanidine, as a renewable source, was modified with an azido linker and coupled by copper-catalyzed alkyne azide cycloaddition to alkynyl derivatives of the monosaccharides found in the natural potato glycoalkakoids: D-glucose, D-galactose and L-rhamnose. The efficacy of our compounds was evaluated on the potato aphid Macrosiphum euphorbiae. The synthetic compounds have stronger aphicidal properties against nymphs than unmodified solanidine. They also showed strong aphicidal activities on adults and a negative impact on fecundity. CONCLUSION: Our synthetic neoglycoalkaloids affected Macrosiphum euphorbiae survival at the nymphal stage as well as at the adult stage. Furthermore, they induced a decrease in fecundity. Our results show that chemical modifications of by-products may afford new sustainable compounds for crop and plant protection. © 2018 Society of Chemical Industry.


Assuntos
Afídeos/efeitos dos fármacos , Solanina/análogos & derivados , Animais , Afídeos/crescimento & desenvolvimento , Diosgenina/farmacologia , Fertilidade/efeitos dos fármacos , Inseticidas/síntese química , Inseticidas/farmacologia , Ninfa/efeitos dos fármacos , Solanina/síntese química , Solanina/farmacologia , Solanum tuberosum/química
9.
Nutrients ; 10(6)2018 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-29799481

RESUMO

The aim of this study is to investigate the potential inhibitory effect of α-chaconine and α-solanine on RL95-2 estrogen receptor (ER) positive human endometrial cancer cell line and to identify the effect of these glycoalkaloids on the Akt signaling and ERα. The cell proliferation profiles and the cytotoxicity studies were performed by Real-Time Cell Analyzer (xCELLigence) and compared with Sulphorhodamine B (SRB) assay. The effects of α-chaconine (2.5, 5, 10 µM), α-solanine (20, 30, 50 µM), API-1 (25 µM) and MPP (20 µM) effects on Akt (Ser473) and ERα (Ser167) expressions evaluated by Western blot and qPCR method. Their IC50 values were as α-chaconine (4.72 µM) < MPP (20.01 µM) < α-solanine (26.27 µM) < API-1 (56.67 µM). 10 µM α-chaconine and 20, 30 and 50 µM α-solanine were effective in decreasing p-Akt(Ser473)/Akt ratio compared to positive control API-1. When the p-ERα/ERα ratios were evaluated, it was observed that α-chaconine (2.5, 5, 10 µM) and α-solanine (50 µM) were as effective as the specific ERα inhibitor MPP in reducing the ratio of p-ERα/ERα compared to the control group. In conclusion, it has been shown that the proliferation of α-chaconine and α-solanine in human endometrial carcinoma cells reduces the expression and activity of the Akt and ERα signaling pathway.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Neoplasias do Endométrio/tratamento farmacológico , Receptor alfa de Estrogênio/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Solanina/análogos & derivados , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação para Baixo , Neoplasias do Endométrio/enzimologia , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/patologia , Receptor alfa de Estrogênio/genética , Feminino , Humanos , Concentração Inibidora 50 , Fosforilação , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais/efeitos dos fármacos , Solanina/farmacologia , Fatores de Tempo
10.
Mol Plant Microbe Interact ; 30(7): 531-542, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28510502

RESUMO

Steroidal glycoalkaloids (SGAs) are plant secondary metabolites known to be toxic to animals and humans and that have putative roles in defense against pests. The proposed mechanisms of SGA toxicity are sterol-mediated disruption of membranes and inhibition of cholinesterase activity in neurons. It has been suggested that phytopathogenic microorganisms can overcome SGA toxicity by enzymatic deglycosylation of SGAs. Here, we have explored SGA-mediated toxicity toward the invasive oomycete Phytophthora infestans, the causative agent of the late blight disease in potato and tomato, as well as the potential for SGA deglycosylation by this species. Our growth studies indicate that solanidine, the nonglycosylated precursor of the potato SGAs α-chaconine and α-solanine, has a greater physiological impact than its glycosylated forms. All of these compounds were incorporated into the mycelium, but only solanidine could strongly inhibit the growth of P. infestans in liquid culture. Genes encoding several glycoside hydrolases with potential activity on SGAs were identified in the genome of P. infestans and were shown to be expressed. However, we found no indication that deglycosylation of SGAs takes place. We present additional evidence for apparent host-specific adaptation to potato SGAs and assess all results in terms of future pathogen management strategies.


Assuntos
Micélio/efeitos dos fármacos , Phytophthora infestans/efeitos dos fármacos , Alcaloides de Solanáceas/farmacologia , Esteroides/farmacologia , Sequência de Carboidratos , Diosgenina/química , Diosgenina/farmacologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Glicosilação , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Solanum lycopersicum/microbiologia , Estrutura Molecular , Micélio/genética , Micélio/fisiologia , Phytophthora infestans/genética , Phytophthora infestans/fisiologia , Doenças das Plantas/microbiologia , Alcaloides de Solanáceas/química , Solanina/análogos & derivados , Solanina/química , Solanina/farmacologia , Solanum tuberosum/microbiologia , Esteroides/química
11.
Food Chem ; 220: 257-265, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27855898

RESUMO

The estimation of glycoalkaloids in the flesh of different types of decayed potatoes was evaluated. The results showed that turned green and also sprouting or rotting potato flesh contain high amounts of toxic solanine and chaconine, exceeding by 2-5-fold the recommended limit, and ranging from 2578±86mg/kg to 5063±230mg/kg of dry weight potato flesh. For safety consideration, these decayed potatoes should be systematically set aside. To avoid a net economic loss and encourage the removal of this hazardous food, a recycling process was investigated to generate added-value compounds from the toxic glycoalkaloids. A simple chemo-enzymatic protocol comprising a partial acidic hydrolysis followed by an enzymatic treatment with the ß-glycosidase from Periplaneta americana allowed the efficient conversion of α-chaconine to solanidine.


Assuntos
Diosgenina/análise , Solanum tuberosum/química , Animais , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Periplaneta/enzimologia , Solanina/análogos & derivados , Solanina/química , beta-Glucosidase/metabolismo
12.
Plant Physiol ; 171(4): 2458-67, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27307258

RESUMO

α-Solanine and α-chaconine, steroidal glycoalkaloids (SGAs) found in potato (Solanum tuberosum), are among the best-known secondary metabolites in food crops. At low concentrations in potato tubers, SGAs are distasteful; however, at high concentrations, SGAs are harmful to humans and animals. Here, we show that POTATO GLYCOALKALOID BIOSYNTHESIS1 (PGA1) and PGA2, two genes that encode cytochrome P450 monooxygenases (CYP72A208 and CYP72A188), are involved in the SGA biosynthetic pathway, respectively. The knockdown plants of either PGA1 or PGA2 contained very little SGA, yet vegetative growth and tuber production were not affected. Analyzing metabolites that accumulated in the plants and produced by in vitro enzyme assays revealed that PGA1 and PGA2 catalyzed the 26- and 22-hydroxylation steps, respectively, in the SGA biosynthetic pathway. The PGA-knockdown plants had two unique phenotypic characteristics: The plants were sterile and tubers of these knockdown plants did not sprout during storage. Functional analyses of PGA1 and PGA2 have provided clues for controlling both potato glycoalkaloid biosynthesis and tuber sprouting, two traits that can significantly impact potato breeding and the industry.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Solanina/análogos & derivados , Solanum tuberosum/enzimologia , Vias Biossintéticas , Cruzamento , Produtos Agrícolas , Sistema Enzimático do Citocromo P-450/genética , Inativação Gênica , Hidroxilação , Fenótipo , Fitosteróis/química , Fitosteróis/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Tubérculos/enzimologia , Tubérculos/genética , Tubérculos/crescimento & desenvolvimento , Solanina/química , Solanina/metabolismo , Solanum tuberosum/genética , Solanum tuberosum/crescimento & desenvolvimento
13.
PLoS One ; 11(5): e0155958, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27213896

RESUMO

Glycoalkaloids are secondary metabolites commonly found in Solanaceae plants. They have anti-bacterial, anti-fungal and insecticidal activities. In the present study we examine the effects of potato and tomato leaf extracts and their main components, the glycoalkaloids α-solanine, α-chaconine and α-tomatine, on development and reproduction of Drosophila melanogaster wild-type flies at different stages. Parental generation was exposed to five different concentrations of tested substances. The effects were examined also on the next, non-exposed generation. In the first (exposed) generation, addition of each extract reduced the number of organisms reaching the pupal and imaginal stages. Parent insects exposed to extracts and metabolites individually applied showed faster development. However, the effect was weaker in case of single metabolites than in case of exposure to extracts. An increase of developmental rate was also observed in the next, non-exposed generation. The imagoes of both generations exposed to extracts and pure metabolites showed some anomalies in body size and malformations, such as deformed wings and abdomens, smaller black abdominal zone. Our results further support the current idea that Solanaceae can be an impressive source of molecules, which could efficaciously be used in crop protection, as natural extract or in formulation of single pure metabolites in sustainable agriculture.


Assuntos
Drosophila melanogaster/fisiologia , Extratos Vegetais/farmacologia , Reprodução/efeitos dos fármacos , Solanum lycopersicum/química , Solanum tuberosum/química , Animais , Tamanho Corporal/efeitos dos fármacos , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/crescimento & desenvolvimento , Feminino , Masculino , Controle Biológico de Vetores , Extratos Vegetais/química , Folhas de Planta/química , Solanina/análogos & derivados , Solanina/farmacologia , Tomatina/análogos & derivados , Tomatina/farmacologia
14.
Molecules ; 21(4): 403, 2016 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-27023503

RESUMO

The present study has found that dried potato samples yielded significantly higher levels of steroidal alkaloids such as α-solanine and α-chaconine than the corresponding fresh samples, as determined by the UPLC-MS/MS technique. Among the drying techniques used, air drying had the highest effect on steroidal alkaloid contents, followed by freeze drying and vacuum oven drying. There was no significant difference between the freeze dried and vacuum oven dried samples in their α-chaconine contents. However, freeze dried potato shoots and berries had significantly higher α-solanine contents (825 µg/g dry weight (DW) in shoots and 2453 µg/g DW in berries) than the vacuum oven dried ones (325 µg/g dry weight (DW) in shoots and 2080 µg/g DW in berries). The kinetics of steroidal alkaloid contents of potato shoots during air drying were monitored over a period of 21 days. Both α-solanine and α-chaconine content increased to their maximum values, 875 µg/g DW and 3385 µg/g DW, respectively, after 7 days of drying. The steroidal alkaloid contents of the shoots decreased significantly at day 9, and then remained unchanged until day 21. In line with the potato shoots, air dried potato tuber peels also had higher steroidal alkaloid content than the freeze dried and vacuum oven dried samples. However, a significant decrease of steroidal alkaloid content was observed in air dried potato berries, possibly due to degradation during slicing of the whole berries prior to air drying. Remarkable variation in steroidal alkaloid contents among different tissue types of potato plants was observed with the potato flowers having the highest content.


Assuntos
Alcaloides/isolamento & purificação , Fitosteróis/isolamento & purificação , Solanina/análogos & derivados , Alcaloides/química , Cromatografia Líquida de Alta Pressão , Liofilização , Frutas/química , Fitosteróis/química , Brotos de Planta/química , Solanina/química , Solanina/isolamento & purificação , Solanum tuberosum/química , Espectrometria de Massas em Tandem
15.
Food Chem ; 200: 263-73, 2016 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26830588

RESUMO

Metabolite profiling (liquid chromatography-mass spectrometry (LC-MS) and gas chromatography (GC-MS)) was used to assess the impact of light on the composition of transgenic potato (Solanum tuberosum L. cv. Desirée) with reduced glycoalkaloid content via the down-regulation of the SGT1 gene. Transgenic tubers exhibited an almost complete knock-out of α-solanine production and light had little impact on its accumulation. Levels of α-chaconine increased significantly in the peel of both the control and transgenic lines when exposed to light, particularly in the transgenic line. Major differences in metabolite profiles existed between outer and inner tuber tissues, and between light and dark-treated tubers. Many of the light-induced changes are explicable in terms of pathways known to be affected by stress responses. The impact of transgenesis on profiles was much less than that of tissue type or light and most differences were explicable in terms of the modification to the glycoalkaloid pathway.


Assuntos
Tubérculos/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Alcaloides de Solanáceas/biossíntese , Solanum tuberosum/metabolismo , Clorofila/análise , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Luz , Espectrometria de Massas , Solanina/análogos & derivados , Solanina/análise , Solanum tuberosum/genética
16.
J Appl Microbiol ; 120(4): 955-65, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26786886

RESUMO

AIMS: To study the antifungal effects of the potato secondary metabolites α-solanine, α-chaconine, solanidine and caffeic acid, alone or combined. METHODS AND RESULTS: Resistance to glycoalkaloids varied among the fungal species tested, as derived from minimum inhibitory concentrations assays. Synergistic antifungal activity between glycoalkaloids and phenolic compounds was found. Changes in the fluidity of fungal membranes caused by potato secondary plant metabolites were determined by calculation of the generalized polarization values. The results partially explained the synergistic effect between caffeic acid and α-chaconine and supported findings on membrane disruption mechanisms from previous studies on artificial membranes. LC/MS analysis was used to determine variability and relative amounts of sterols in the different fungal species. Results suggested that the sterol pattern of fungi is related to their resistance to potato glycoalkaloids and to their taxonomy. CONCLUSION: Fungal resistance to α-chaconine and possibly other glycoalkaloids is species dependent. α-Chaconine and caffeic acid show synergistic antifungal activity. The taxonomic classification and the sterol pattern play a role in fungal resistance to glycoalkaloids. SIGNIFICANCE AND IMPACT OF THE STUDY: Results improve the understanding of the antifungal mode of action of potato secondary metabolites, which is essential for their potential utilization as antifungal agents in nonfood systems.


Assuntos
Antifúngicos/farmacologia , Diosgenina/farmacologia , Fungos/efeitos dos fármacos , Solanina/análogos & derivados , Antifúngicos/isolamento & purificação , Antifúngicos/metabolismo , Ácidos Cafeicos/isolamento & purificação , Ácidos Cafeicos/metabolismo , Ácidos Cafeicos/farmacologia , Diosgenina/isolamento & purificação , Diosgenina/metabolismo , Testes de Sensibilidade Microbiana , Fenóis/metabolismo , Solanina/isolamento & purificação , Solanina/metabolismo , Solanina/farmacologia , Solanum tuberosum/metabolismo
17.
J Agric Food Chem ; 64(4): 988-96, 2016 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-26768994

RESUMO

Before commercial release, new potato (Solanum tuberosum) varieties must be evaluated for content of toxic compounds such as glycoalkaloids (GAs), which are potent poisons. GA biosynthesis proceeds via the cholesterol pathway to α-chaconine and α-solanine. The goal of this study was to evaluate the relationship between total glycoalkaloid (TGA) content and the expression of GAME, SGT1, and SGT3 genes in potato tubers. TGA content was measured by HPLC-MS, and reverse transcription quantitative polymerase chain reactions were performed to determine the relative expression of GAME, SGT1, and SGT3 genes. We searched for cis-elements of the transcription start site using the PlantPAN database. There was a relationship between TGA content and the relative expression of GAME, SGT1, and SGT3 genes in potato tubers. Putative promoter regions showed the presence of several cis-elements related to biotic and abiotic stresses and light. These findings provide an important step toward understanding TGA regulation and variation in potato tubers.


Assuntos
Alcaloides/biossíntese , Proteínas de Plantas/genética , Solanum tuberosum/genética , Solanum tuberosum/metabolismo , Transcrição Gênica , Alcaloides/toxicidade , Vias Biossintéticas , Proteínas de Plantas/metabolismo , Tubérculos/química , Tubérculos/genética , Tubérculos/metabolismo , Regiões Promotoras Genéticas , Solanina/análogos & derivados , Solanina/metabolismo , Solanina/toxicidade
18.
Molecules ; 20(5): 8560-73, 2015 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-25985357

RESUMO

A higher yield of glycoalkaloids was recovered from potato peels using pressurized liquid extraction (1.92 mg/g dried potato peels) compared to conventional solid-liquid extraction (0.981 mg/g dried potato peels). Response surface methodology deduced the optimal temperature and extracting solvent (methanol) for the pressurized liquid extraction (PLE) of glycoalkaloids as 80 °C in 89% methanol. Using these two optimum PLE conditions, levels of individual steroidal alkaloids obtained were of 597, 873, 374 and 75 µg/g dried potato peel for α-solanine, α-chaconine, solanidine and demissidine respectively. Corresponding values for solid liquid extraction were 59%, 46%, 40% and 52% lower for α-solanine, α-chaconine, solanidine and demissidine respectively.


Assuntos
Alcaloides/metabolismo , Compostos Fitoquímicos/metabolismo , Solanum tuberosum/metabolismo , Extração em Fase Sólida/métodos , Diosgenina/metabolismo , Metanol/química , Alcaloides de Solanáceas/metabolismo , Solanina/análogos & derivados , Solanina/metabolismo
19.
Chem Biol Interact ; 235: 85-94, 2015 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-25913072

RESUMO

In this study, we investigated the molecular mechanisms underlying the anti-inflammatory effects of α-chaconine in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages and in LPS-induced septic mice. α-Chaconine inhibited the expressions of cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor-α (TNF-α) at the transcriptional level, and attenuated the transcriptional activity of activator protein-1 (AP-1) by reducing the translocation and phosphorylation of c-Jun. α-Chaconine also suppressed the phosphorylation of TGF-ß-activated kinase-1 (TAK1), which lies upstream of mitogen-activated protein kinase kinase 7 (MKK7)/Jun N-terminal kinase (JNK) signaling. JNK knockdown using siRNA prevented the α-chaconine-mediated inhibition of pro-inflammatory mediators. In a sepsis model, pretreatment with α-chaconine reduced the LPS-induced lethality and the mRNA and production levels of pro-inflammatory mediators by inhibiting c-Jun activation. These results suggest that the anti-inflammatory effects of α-chaconine are associated with the suppression of AP-1, and support its possible therapeutic role for the treatment of sepsis.


Assuntos
Endotoxinas/metabolismo , Inflamação/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Solanina/análogos & derivados , Solanum tuberosum/química , Fator de Transcrição AP-1/metabolismo , Animais , Linhagem Celular , Ciclo-Oxigenase 2/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , MAP Quinase Quinase 4/metabolismo , MAP Quinase Quinase 7 , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação/efeitos dos fármacos , Solanina/farmacologia , Fator de Crescimento Transformador beta/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
20.
J Agric Food Chem ; 63(13): 3323-37, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-25821990

RESUMO

Inhibition of cancer can occur via apoptosis, a genetically directed process of cell self-destruction that involves numerous biomarkers and signaling pathways. Glycoalkaloids are nitrogen-containing secondary plant metabolites found in numerous Solanaceous plants including eggplants, potatoes, and tomatoes. Exposure of cancer cells to glycoalkaloids produced by eggplants (α-solamargine and α-solasonine), potatoes (α-chaconine and α-solanine), and tomatoes (α-tomatine) or their hydrolysis products (mono-, di-, and trisaccharide derivatives and the aglycones solasodine, solanidine, and tomatidine) inhibits the growth of the cells in culture (in vitro) as well as tumor growth in vivo. This overview comprehensively surveys and consolidates worldwide efforts to define the following aspects of these natural compounds: (a) their prevalence in the three foods; (b) their chemistry and structure-activity relationships; (c) the reported factors (biomarkers, signaling pathways) associated with apoptosis of bone, breast, cervical, colon, gastric, glioblastoma, leukemia, liver, lung, lymphoma, melanoma, pancreas, prostate, and squamous cell carcinoma cell lines in vitro and the in vivo inhibition of tumor formation and growth in fish and mice and in human skin cancers; and (d) future research needs. The described results may make it possible to better relate the structures of the active compounds to their health-promoting function, individually, in combination, and in food, and allow the consumer to select glycoalkaloid-containing food with the optimal content of nontoxic beneficial compounds. The described findings are expected to be a valuable record and resource for further investigation of the health benefits of food-related natural compounds.


Assuntos
Anticarcinógenos , Alcaloides de Solanáceas/química , Alcaloides de Solanáceas/farmacologia , Solanum lycopersicum/metabolismo , Solanum melongena/metabolismo , Solanum tuberosum/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Camundongos , Alcaloides de Solanáceas/biossíntese , Solanina/análogos & derivados , Solanina/farmacologia , Relação Estrutura-Atividade , Tomatina/análogos & derivados , Tomatina/farmacologia
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