RESUMO
BACKGROUND: The UDP-glucuronosyltransferase 91D2 (SrUGT91D2) gene is a crucial element in the biosynthetic pathway of steviol glycosides (SGs) and is responsible for creating 1,2-ß-D glucosidic bonds at the C19 and C13 positions. This process plays a vital role in the synthesis of rebaudioside M (RM) and rebaudioside D (RD). The promoter, which regulates gene expression, requires functional analysis to understand gene expression regulation. However, investigations into the function of the promoter of SrUGT91D2 (pSrUGT91D2) have not been reported. RESULTS: The pSrUGT91D2 was isolated from six S. rebaudiana lines, and subsequent multiple sequence comparisons revealed the presence of a 26 bp inDel fragment (pSrUGT91D2-B1188 type) in lines GP, GX, 110, 1114, and B1188 but not in the pSrUGT91D2 of line 023 (pSrUGT91D2-023 type). Bioinformatics analysis revealed a prevalence of significant cis-regulatory elements (CREs) within the promoter sequences, including those responsive to abscisic acid, light, anaerobic conditions, auxin, drought, low temperature, and MeJA. To verify the activity of pSrUGT91D2, the full-length promoter and a series of 5' deletion fragments (P1-P7) and a 3' deletion fragment (P8) from various lines were fused with the reporter ß-glucuronidase (GUS) gene to construct the plant expression vector, pCAMBIA1300-proâ·GUS. The transcriptional activity of these genes was examined in tobacco leaves through transient transformation. GUS tissue staining analysis and enzyme activity assays demonstrated that both the full-length promoter and truncated pSrUGT91D2 were capable of initiating GUS expression in tobacco leaves. Interestingly, P8-pSrUGT91D2-B1188 (containing the inDel segment, 301 bp) exhibited enhanced activity in driving GUS gene expression. Transient expression studies of P8-pSrUGT91D2-B1188 and P8-pSrUGT91D2-023 in response to exogenous hormones (abscisic acid and indole-3-acetic acid) and light indicated the necessity of the inDel region for P8 to exhibit transcriptional activity, as it displayed strong responsiveness to abscisic acid (ABA), indole-3-acetic acid (IAA), and light induction. CONCLUSIONS: These findings contribute to a deeper understanding of the regulatory mechanism of the upstream region of the SrUGT91D2 gene and provide a theoretical basis for future studies on the interaction between CREs of pSrUGT91D2 and related transcription factors.
Assuntos
Regulação da Expressão Gênica de Plantas , Reguladores de Crescimento de Plantas , Regiões Promotoras Genéticas , Stevia , Estresse Fisiológico , Regiões Promotoras Genéticas/genética , Stevia/genética , Stevia/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Estresse Fisiológico/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Diterpenos do Tipo Caurano/metabolismoRESUMO
Stevioside (5-10%) and rebaudioside-A (2-4%) are well-characterized diterpene glycosides found in leaves of Stevia rebaudiana known to have natural sweetening properties with zero glycaemic index. Stevioside has after-taste bitterness, whereas rebaudioside-A is sweet in taste. The ratio of rebaudioside-A to stevioside needs to be changed in order to increase the effectiveness and palatability of this natural sweetener. Plant-specific miRNAs play a significant role in the regulation of metabolic pathways for the biosynthesis of economically important secondary metabolites. In this study inhibition of miRNA through antisense technology was employed to antagonize the repressive action of miRstv_7 on its target mRNAs involved in the steviol glycosides (SGs) biosynthesis pathway. In transgenic plants expressing anti-miRstv_7, reduced expression level of endogenous miRstv_7 was observed than the non-transformed plants. As a result, enhanced expression of target genes, viz. KO (Kaurene oxidase), KAH (Kaurenoic acid-13-hydroxylase), and UGT76G1 (UDP-glycosyltransferase 76G1) led to a significant increase in the rebaudioside-A to stevioside ratio. Furthermore, metabolome analysis revealed a significant increase in total steviol glycosides content as well as total flavonoids content. Thus, our study can be utilized to generate more palatable varieties of Stevia with improved nutraceutical values including better organoleptic and antioxidant properties.
Assuntos
Antioxidantes , Vias Biossintéticas , Diterpenos do Tipo Caurano , MicroRNAs , Stevia , Stevia/genética , Stevia/metabolismo , Diterpenos do Tipo Caurano/metabolismo , Antioxidantes/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Vias Biossintéticas/genética , Glucosídeos/metabolismo , Glucosídeos/biossíntese , Plantas Geneticamente Modificadas , Edulcorantes/farmacologia , Edulcorantes/metabolismo , Regulação da Expressão Gênica de Plantas , Folhas de Planta/metabolismo , Folhas de Planta/genética , Glicosídeos/biossíntese , Glicosídeos/metabolismoRESUMO
Depending on the texture of soil, different physicochemical and microbiological parameters are characterized, and these characteristics are influenced by crop cultivation. Stevia, a popular zero-calorie sweetener crop, is widely cultivated around the world on various soil textures. Sandy loam and clay soil show great differences in physicochemical and biological parameters and are often used for Stevia cultivation. To understand the effects of Stevia cultivation on soil physicochemical and biological features, we investigated the changes of physicochemical and microbiological parameters in sandy loam and clay soil following Stevia cultivation. This study was carried out through different physiological and biochemical assays and microbiomic analysis. The results indicated that the sandy loam soil had significantly lower pH and higher nutrient content in the rhizosphere and bulk soils after the Stevia cultivation. The sandy loam soil maintained higher bacterial diversity and richness than the clay soil after Stevia harvest. Beneficial bacteria such as Dongia, SWB02, Chryseolinea, Bryobacter and Devosia were enriched in the sandy loam soil; however, bacteria such as RB41, Haliangium and Ramlibacter, which are unfavorable for nutrient accumulation, predominated in clay soil. Redundancy analysis indicated that the variation in the composition of bacterial community was mainly driven by soil pH, organic matter, total nitrogen, available phosphorus, and microbial biomass phosphorus. This study provides a deeper understanding of physicochemical and microbiological changes in different soil textures after Stevia cultivation and guidance on fertilizer management for Stevia rotational cultivation.
Assuntos
Argila , Microbiota , Microbiologia do Solo , Solo , Stevia , Stevia/química , Stevia/crescimento & desenvolvimento , Microbiota/efeitos dos fármacos , Solo/química , Argila/química , Concentração de Íons de Hidrogênio , Areia/microbiologia , Bactérias/crescimento & desenvolvimento , Bactérias/efeitos dos fármacos , RizosferaRESUMO
BACKGROUND: Misfolded proteins accumulate in the liver due to endoplasmic reticulum stress (ERS) caused by high blood glucose levels in diabetes. This triggers the unfolded protein response (UPR), which if persistently activated, results in cellular dysfunction. Chronic ER stress increases inflammation, insulin resistance, and apoptosis. There is growing interest in using native plants and traditional medicine for diabetes treatment. The stevia plant has recently gained attention for its potential therapeutic effects. This study investigates the protective effects of aquatic stevia extract on liver damage, ER stress, and the UPR pathway in streptozotocin (STZ)-induced diabetic rats. METHODS: Rats were randomly divided into four groups: a control group that received 1 ml of water; a diabetic group induced by intraperitoneal injection of STZ (60 mg/kg); a diabetic group treated with metformin (500 mg/kg); and a diabetic group treated with aquatic extracts of stevia (400 mg/kg). After 28 days, various parameters were assessed, including inflammatory markers, oxidative stress indices, antioxidant levels, gene expression, stereology, and liver tissue pathology. RESULT: Compared to the diabetic control group, treatment with stevia significantly decreased serum glucose, liver enzymes, inflammatory markers, and oxidative stress while increasing body weight and antioxidant levels. Additionally, stevia extract manipulated UPR gene expression and reduced apoptosis pathway activation. Histological examination revealed improved liver tissue morphology in stevia-treated diabetic rats. CONCLUSION: These findings suggest that aquatic stevia extract mitigates ER stress in diabetic rats by modulating the IRE-1 arm of the UPR and apoptosis pathways, highlighting its potential therapeutic benefits for diabetes-related liver complications.
Assuntos
Diabetes Mellitus Experimental , Estresse do Retículo Endoplasmático , Fígado , Estresse Oxidativo , Extratos Vegetais , Stevia , Animais , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Stevia/química , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Extratos Vegetais/farmacologia , Ratos , Masculino , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Estresse Oxidativo/efeitos dos fármacos , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Estreptozocina , Apoptose/efeitos dos fármacos , Antioxidantes/farmacologia , Hipoglicemiantes/farmacologiaRESUMO
Cestodes are etiological agents of neglected diseases such as echinococcosis and cysticercosis, which are major public health problems. Antiparasitic treatment relies on a small number of approved drugs, which are often only partially effective, poorly tolerated and require prolonged administration. Thus, the discovery of novel potential treatments is critical. The Stevia genus (Asteraceae) includes species that are recognized as a source of bioactive compounds, with many species associated with medicinal uses. In this study, the cestocidal activity of four South American Stevia species that previously showed antiprotozoal activity was analyzed using a motility assay on the laboratory cestode model, Mesocestoides vogae. The four Stevia extracts showed cestocidal activity, with S. alpina var. alpina as the most active. The sesquiterpene lactones estafietin and eupatoriopicrin were purified from S. alpina var. alpina and S. maimarensis, respectively, and tested on M. vogae. Estafietin showed cestocidal activity, inhibiting parasite viability in a dose-dependent manner, even from the first day of incubation. Consistent with the motility effects, the extract of S. alpina var. alpina and estafietin induced marked alterations in the morphology of the parasite. The results of this report show that Stevia species represent a source of new molecules with potential for the treatment of neglected tropical diseases caused by cestodes.
Assuntos
Anti-Helmínticos , Extratos Vegetais , Stevia , Stevia/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Animais , Anti-Helmínticos/farmacologia , Anti-Helmínticos/química , Terpenos/química , Terpenos/farmacologia , Cestoides/efeitos dos fármacos , Doenças Negligenciadas/tratamento farmacológico , Infecções por Cestoides/tratamento farmacológico , Mesocestoides/efeitos dos fármacosRESUMO
Stevia rebaudiana (Bertoni), commonly known as stevia, is a sought-after natural sweetener, but its conventional propagation methods are slow and inefficient. This study aims to enhance the in vitro culture for stevia by investigating the impact of different Murashige and Skoog (MS) medium salt strengths and plant growth hormones on growth and rebaudioside A content. Apical bud-containing shoot segments were used as explants and cultured on various semi-solid and liquid MS media formulations, incorporating cytokinins (BAP and Kin), auxins (NAA and IAA), and different MS major salt concentrations (MS full, ½ MS, and » MS). Assessments of shoot growth parameters, root formation, and HPLC analysis for rebaudioside A content were conducted. The optimal conditions for in vitro growth was found to be in the » MS + Kin 3 mg/L + NAA 0.1 mg/L (semi-solid) medium, resulting in significantly improved shoot growth and enhanced 30.04% rebaudioside A content. Genetic fidelity of regenerated plants was confirmed using RAPD and ISSR markers. These findings offer valuable insights for optimizing in vitro propagation of stevia and potentially enhancing rebaudioside A content.
Assuntos
Meios de Cultura , Diterpenos do Tipo Caurano , Reguladores de Crescimento de Plantas , Brotos de Planta , Stevia , Stevia/crescimento & desenvolvimento , Stevia/efeitos dos fármacos , Stevia/metabolismo , Stevia/química , Diterpenos do Tipo Caurano/metabolismo , Meios de Cultura/química , Reguladores de Crescimento de Plantas/farmacologia , Reguladores de Crescimento de Plantas/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Cloreto de Sódio/farmacologiaRESUMO
BACKGROUND: The study investigates substituting non-nutritive sweeteners (NNS) for sugar to address health concerns related to excess sugar intake. It specifically examines how stevia affects insulin and blood glucose levels. The systematic review and meta-analysis aim to evaluate stevia's impact on glycemic indices. METHODS: We conducted a systematic review and meta-analysis following PRISMA guidelines, including 26 studies with 1439 participants. The PROSPERO registration number for this research is CRD42023414411. We systematically searched PubMed (MEDLINE), Scopus, Web of Science, and Google Scholar. Additionally, we thoroughly reviewed the reference lists of the articles we extracted and relevant reviews. Two evaluators independently carried out screening, quality assessment, and data extraction. The GRADE (grading of recommendations, assessment, development, and evaluation) approach was utilized to evaluate the certainty of the evidence. RESULTS: Stevia consumption was associated with significantly reducing blood glucose levels (WMD: -3.84; 95 % CI: -7.15, -0.53; P = 0.02, low certainty), especially in individuals with higher BMI, diabetes, and hypertension. Dose-response analysis revealed a decrease in blood glucose for ≥3342 mg/day of stevia consumption. Stevia consumption has been shown to reduce blood glucose levels within 1-4 months, as evidenced by dose-response analysis (less than 120 days) and subgroup analysis (more than four weeks). However, stevia did not significantly affect insulin concentration or HbA1C levels (very low and low certainty, respectively). CONCLUSIONS: Low certainty evidence showed that stevia improved blood glucose control, especially when consumed for less than 120 days. However, more randomized trials with higher stevia dosages are required.
Assuntos
Glicemia , Hemoglobinas Glicadas , Stevia , Edulcorantes , Humanos , Stevia/química , Glicemia/análise , Glicemia/efeitos dos fármacos , Hemoglobinas Glicadas/análise , PrognósticoRESUMO
The rapid increase in the worldwide prevalence of obesity and certain non-communicable diseases (NCDs), such as: cardiovascular diseases, cancers, chronic respiratory diseases, and diabetes, has been mainly attributed to an excess of sugar consumption. Although the potential benefits of the synergetic use of sweeteners have been known for many years, recent development based on synthesis strategies to produce sucrose-like taste profiles is emerging where biocatalyst approaches may be preferred to produce and supply specific sweetener compounds. From a nutritional standpoint, high-intensity sweeteners have fewer calories than sugars while providing a major sweet potency, placing them in the spotlight as valuable alternatives to sugar. Due to the modern world awareness and incidence of metabolic diseases, both food research and growing markets have focused on two generally regarded as safe (GRAS) groups of compounds: the sweet diterpenoid glycosides present on the leaves of Stevia rebaudiana and, more recently, on the cucurbitane triterpene glycosides present on the fruits of Siraitia grosvenorii. In spite of their flavor advantages, biological benefits, including: antidiabetic, anticancer, and cardiovascular properties, have been elucidated. The present bibliographical review dips into the state-of-the-art of sweeteners and their role in human health as sugar replacements, as well as the biotransformation methods for steviol gylcosides and mogrosides apropos of enzymatic technology to update and locate the discoveries to date in the scientific literature to help boost the continuity of research efforts of the ongoing sweeteners.
Assuntos
Stevia , Edulcorantes , Humanos , Cucurbitaceae/metabolismoRESUMO
Steviol glycosides (SGs) are a natural sweetener widely used in the food and beverage industry, but the low solubility and stability of SG aqueous solutions greatly limit their application performance, especially in liquid formulations. In this work, we explore the solubility behavior of rebaudioside A (Reb A) in water, a major component of SGs, with the aim of clarifying the underlying mechanisms of the solubility and stability constraints of SGs, as well as the impact on their multifunctional properties. We demonstrate for the first time that Reb A exhibits hierarchical self-assembly in solutions, forming spherical micelles first when the concentration exceeds its critical micelle concentration (5.071 mg/mL), which then further assemble into large rod-like aggregates. The formation of such large Reb A aggregates is mainly dominated by hydrogen bonding and short-range Coulomb interaction energy, thus leading to the low solubility and precipitation of Reb A solutions. Surprisingly, aggregated Reb A structures display significantly improved organoleptic properties, revealing that self-aggregation can be developed as a simple, efficient, and green strategy for improving the taste profile of SGs. Additionally, the self-aggregation of Reb A at high concentrations impairs active encapsulation and also affects its interfacial and emulsifying properties.
Assuntos
Diterpenos do Tipo Caurano , Glicosídeos , Solubilidade , Edulcorantes , Diterpenos do Tipo Caurano/química , Edulcorantes/química , Glicosídeos/química , Água/química , Micelas , Ligação de Hidrogênio , Paladar , Glucosídeos/química , Stevia/química , Soluções/químicaRESUMO
Given the low-calorie, high-sweetness characteristics of steviol glycosides (SGs), developing SGs with improved taste profiles is a key focus. Rebaudioside M8 (Reb M8), a novel non-natural SG derivative obtained through glycosylation at the C-13 position of rebaudioside D (Reb D) using glycosyltransferase UGT94E13, holds promise for further development due to its enhanced sweetness. However, the low catalytic activity of UGT94E13 hampers further research and commercialization. This study aimed to improve the enzymatic activity of UGT94E13 through semirational design, and a variant UGT94E13-F169G/I185G was obtained with the catalytic activity improved by 13.90 times. A cascade reaction involving UGT94E13-F169G/I185G and sucrose synthase AtSuSy was established to recycle uridine diphosphate glucose, resulting in an efficient preparation of Reb M8 with a yield of 98%. Moreover, according to the analysis of the distances between the substrate Reb D and enzymes as well as between Reb D and the glucose donor through molecular dynamics simulations, it is found that the positive effect of shortening the distance on glycosylation reaction activity accounts for the improved catalytic activity of UGT94E13-F169G/I185G. Therefore, this study addresses the bottleneck in the efficient production of Reb M8 and provides a foundation for its widespread application in the food industry.
Assuntos
Diterpenos do Tipo Caurano , Glicosiltransferases , Diterpenos do Tipo Caurano/química , Diterpenos do Tipo Caurano/metabolismo , Glicosiltransferases/metabolismo , Glicosiltransferases/química , Glicosiltransferases/genética , Glicosilação , Edulcorantes/química , Edulcorantes/metabolismo , Stevia/química , Stevia/enzimologia , Stevia/metabolismo , Stevia/genética , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Engenharia de Proteínas , Glucosiltransferases/química , Glucosiltransferases/metabolismo , Glucosiltransferases/genética , GlicosídeosRESUMO
Stevia rebaudiana (stevia) is a plant in the Asteraceae that contains several biologically active compounds including the antidiabetic diterpene glycosides (e.g. stevioside, rebaudioside and dulcoside) that can serve as zero-calorie sugar alternatives. In this study, an elicitation strategy was applied using 5% polyethylene glycol (PEG), sodium chloride (NaCl; 50 and 100 mM) and gibberellic acid (2.0 and 4.0 mg/L GA3) to investigate their effect on shoot morphogenesis, and the production of phenolics, flavonoids, total soluble sugars, proline and stevioside, as well as antioxidant activity, in shoot cultures of S. rebaudiana. Herewith, the media supplemented with 2 mg/L and 4 mg/L GA3 exhibited the highest shooting response (87% and 80%). The augmentation of lower concentrations of GA3 (2 mg/L) in combination with 6-benzylaminopurine (BAP) resulted in the maximum mean shoot length (11.1 cm). The addition of 100 mM NaCl salts to the media led to the highest observed total phenolics content (TPC; 4.11 mg/g-DW compared to the control 0.52 mg/g-DW), total flavonoids content (TFC; 1.26 mg/g-DW) and polyphenolics concentration (5.39 mg/g-DW) in shoots cultured. However, the maximum antioxidant activity (81.8%) was observed in shoots raised in media treated with 50 mM NaCl. The application of 2 mg/L of GA3 resulted in the highest accumulation of proline (0.99 µg/mL) as compared to controls (0.37 µg/mL). Maximum stevioside content (71 µL/mL) was observed in cultures supplemented with 100 mM NaCl and 5% PEG, followed by the 4 mg/L GA3 treatment (70 µL/mL) as compared to control (60 µL/mL). Positive correlation was observed between GA3 and stevioside content. Notably, these two compounds are derived from a shared biochemical pathway. These results suggest that elicitation is an effective option to enhance the accumulation of steviosides and other metabolites and provides the groundwork for future industrial scale production using bioreactors.
Assuntos
Antioxidantes , Diterpenos do Tipo Caurano , Giberelinas , Glucosídeos , Brotos de Planta , Stevia , Stevia/metabolismo , Stevia/crescimento & desenvolvimento , Stevia/efeitos dos fármacos , Diterpenos do Tipo Caurano/metabolismo , Glucosídeos/metabolismo , Brotos de Planta/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/efeitos dos fármacos , Giberelinas/metabolismo , Antioxidantes/metabolismo , Metabolismo Secundário , Flavonoides/metabolismo , Flavonoides/análise , Fenóis/metabolismo , Cloreto de Sódio/farmacologia , Purinas/metabolismo , Prolina/metabolismo , Polietilenoglicóis/farmacologia , Polietilenoglicóis/química , Compostos de BenzilRESUMO
PURPOSE: Stevia rebaudiana Bertoni is a perennial herb, widely used as a natural sweetener around the globe. The key compounds responsible for its sweetness includes stevioside and rebaudioside-A. In order to improve these steviol glycosides, the present study was initiated to study the effect of induced mutagenesis on growth parameters, steviol glycosides and nuclear DNA content in Stevia rebaudiana Bertoni using ten doses of gamma-rays (5-100 kR). MATERIALS AND METHODS: Healthy seeds of 'Madhuguna' variety of Stevia rebaudiana Bertoni developed and maintained at stevia breeding farm, Agrotechnology division, CSIR-Institute of Himalayan Bioresource Technology, Palampur (HP), India were irradiated with ten doses of gamma rays (600 seeds each/dose) ranging from 5 kR to 100 kR (i.e., 5, 10, 15, 20, 30, 40, 50, 60, 80 and 100 kR) using Co60 gamma irradiation chamber at CCS Haryana Agricultural University, Hisar, (Haryana), India. RESULTS: Significant variations were recorded for all the seedling traits studied while major impact was noticed on the seedling after reaching the cotyledonary stage and doses above 40 kR showed absolute mortality of the seedlings. Based on probit analysis, the optimum LD50 dose lies in the range of 20-23 kR. Glycosidic profiling of 296 mutants using high-performance liquid chromatography showed decreased total steviol glycoside content with increased radiation dose. Doses 5 kR and 10 kR, were found to be effective in increasing the overall glycosidic content. A total of 72 promising mutants were also screened for increased rebaudioside-A stevioside ratio. Comparison of nuclear DNA content using flow cytometry revealed a similar decrease in the total nuclear DNA content with increase in dosage of gamma rays. The average genome size at 5, 10, 15, 20 and 30 kR treatments were 2.72, 2.69, 2.68, 2.70 and 2.66 pg as compared to 2.72 pg in control. CONCLUSIONS: Mild dose of gamma rays (5 and 10 kR) in stevia were found to be effective in improving the mean steviol glycoside content and may be used in future stevia mutation programmes.
Assuntos
Diterpenos do Tipo Caurano , Raios gama , Stevia , Stevia/efeitos da radiação , Tolerância a Radiação , Glucosídeos , Relação Dose-Resposta à RadiaçãoRESUMO
OBJECTIVES: It is unclear whether parental consumption of non-nutritive sweetener (NNS) can affect subsequent generations. The aim of this study was to determine whether chronic parental consumption of sucralose and stevia in mice affects body weight gain and liver and intestinal expression of histone deacetylase 3 (Hdac3) in these animals and in the subsequent first filial (F1) and second filial (F2) generations. METHODS: Male and female mice (n = 47) were divided into three groups to receive water alone or supplemented with sucralose (0.1 mg/mL) or stevia (0.1 mg/mL) for 16 wk (parental [F0] generation). F0 mice were bred to produce the F1 generation; then, F1 mice were bred to produce the F2 generation. F1 and F2 animals did not receive NNSs. After euthanasia, hepatic and intestinal expression of Hdac3 was determined by quantitative reverse transcription polymerase chain reaction. RESULTS: Body weight gain did not differ between the three groups in the F0 generation, but it was greater in the F1 sucralose and stevia groups than in the control group. Consumption of both NNSs in the F0 generation was associated with lower Hdac3 expression in the liver and higher in the intestine. Hepatic Hdac3 expression was normalized to the control values in the F1 and F2 animals of the sucralose and stevia groups. Intestinal expression was still higher in the F1 generations of the sucralose and stevia groups but was partially normalized in the F2 generation of these groups, compared with control. CONCLUSIONS: NNS consumption differentially affects hepatic and intestinal Hdac3 expression. Changes in hepatic expression are not transmitted to the F1 and F2 generations whereas those in intestinal expression are enhanced in the F1 and attenuated in the F2 generations.
Assuntos
Histona Desacetilases , Fígado , Stevia , Sacarose , Edulcorantes , Animais , Histona Desacetilases/metabolismo , Histona Desacetilases/genética , Masculino , Sacarose/análogos & derivados , Sacarose/farmacologia , Feminino , Camundongos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Edulcorantes/farmacologia , Aumento de Peso/efeitos dos fármacos , Adoçantes não Calóricos/farmacologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Peso Corporal/efeitos dos fármacosRESUMO
Septoria leaf spot is a significant disease affecting cultivated stevia, potentially reducing yields by > 50%. The disease is caused by Septoria steviae, first identified in 1978 in Japan as a new pathogen of stevia. Understanding the origin of S. steviae could clarify how it spread to new production areas. To investigate this, 12 isolates of Septoria sp. were obtained from stevia's native range in the Amambay forests and field plantings in Paraguay from 2018 to 2020. These isolates underwent colony morphology and molecular characterization of Actin, ß-Tubulin, Calmodulin, ITS, LSU, RPB2, and TEF1α loci. GenBank sequences from S. steviae isolates collected in France, Japan, and the United States were included. Multilocus sequence phylogenetic analysis generated a maximum likelihood (ML) tree. The morphological characteristics of Paraguayan isolates were similar to those of previously reported S. steviae type cultures from Japan. The ML analysis showed that Paraguayan isolates formed a monophyletic group with S. steviae isolates from France, Japan, and the United States. During blotter tests, pycnidia and cirri of S. steviae were observed on multiple stevia seed surfaces from different sources. Further characterization confirmed viable pathogenic conidia of S. steviae. This observation suggests that S. steviae could be associated with stevia seed, possibly spreading from the center of origin to other countries. This research is the first to genetically characterize S. steviae from Paraguay and propose its potential spread mechanism from the center of origin to the rest of the world.
Assuntos
Filogenia , Doenças das Plantas , Stevia , Doenças das Plantas/microbiologia , Stevia/microbiologia , Ascomicetos/genética , Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Tipagem de Sequências Multilocus , Paraguai , Folhas de Planta/microbiologia , JapãoRESUMO
Herbal infusions exhibit diverse pharmacological effects, such as antioxidant, anti-inflammatory, anticancer, antihypertensive, and antineurodegenerative activities, which can be attributed to the high content of phenolic compounds (e.g., caffeoylquinic acids (CQAs)). In this study, we used ultraperformance liquid chromatography to determine the content of CQAs in the methanolic extracts of model herbs, namely, yerba mate (Ilex paraguariensis), stevia (Stevia rebaudiana), and Indian camphorweed (Pluchea indica (L.) Less.). The results revealed that yerba mate had the highest total CQA content (108.05 ± 1.12 mg/g of dry weight). Furthermore, we evaluated the effect of brewing conditions and storage at 4 °C under dark and light conditions on the antioxidant property and total phenolic and CQA contents of a yerba mate infusion. The analysis of the yerba mate infusions prepared with different steeping times, dried leaf weights, and water temperatures revealed that the amount of extracted CQAs was maximized (â¼175 mg/150 mL) when 6 g of dried leaves were steeped in hot water for 10 min. A total of 10-day refrigerated storage resulted in no significant changes in the antioxidant activity and total phenolic and CQA contents of an infusion kept in a brown container (dark). However, the antioxidant properties and total phenolic and CQA contents were negatively affected when kept in a clear container, suggesting the detrimental effect of light exposure. Our study provides practical recommendations for improving the preparation and storage of herbal infusions, thus catering to the needs of consumers, food scientists, and commercial producers. Moreover, it is the first study of the influence of light exposure on the content of crucial quality attributes within plant-based beverages.
Assuntos
Antioxidantes , Ilex paraguariensis , Extratos Vegetais , Ácido Quínico , Stevia , Ilex paraguariensis/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Ácido Quínico/análogos & derivados , Ácido Quínico/análise , Stevia/química , Antioxidantes/farmacologia , Antioxidantes/análise , Fenóis/análise , Temperatura Baixa , Folhas de Planta/química , Armazenamento de MedicamentosRESUMO
For health and safety reasons, the search for green, healthy, and low-calorie sweeteners with good taste has become the demand of many consumers. Furthermore, the need for sugar substitutes of natural origin has increased dramatically. In this review, we briefly discussed the safety and health benefits of stevia sweeteners and enumerated some examples of physiological functions of steviol glycosides (SGs), such as anti-inflammatory, anti-obesity, antihypertensive, anti-diabetes, and anticaries, citing various evidence related to their application in the food industry. The latest advances in emerging technologies for extracting and purifying SGs and the process variables and operational strategies were discussed. The impact of the extraction methods and their comparison against the conventional techniques have also been demonstrated. These technologies use minimal energy solvents and simplify subsequent purification stages, making viable alternatives suitable for a possible industrial application. Furthermore, we also elucidated the potential for advancing and applying the natural sweeteners SGs.
Assuntos
Diterpenos do Tipo Caurano , Extratos Vegetais , Stevia , Edulcorantes , Stevia/química , Diterpenos do Tipo Caurano/isolamento & purificação , Diterpenos do Tipo Caurano/química , Edulcorantes/isolamento & purificação , Edulcorantes/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Humanos , Glucosídeos/isolamento & purificação , Glucosídeos/química , Animais , Glicosídeos/isolamento & purificação , Glicosídeos/químicaRESUMO
Stevia rebaudiana Bertoni is a plant native to South America that has gathered much interest in recent decades thanks to diterpene glycosides, called steviosides, which it produces. These compounds are characterised by their sweetness, which is 250-300 times higher than saccharose, and they contain almost no caloric value. Stevia is currently also grown outside the South American continent, in various countries characterised by warm weather. This research aimed to determine whether it is viable to grow Stevia rebaudiana plants in Poland, a country characterised by a cooler climate than the native regions for stevia plants. Additionally, the impact of adding various dosages and forms of nitrogen fertiliser was analysed. It was determined that Stevia rebaudiana grown in Poland is characterised by a rather low concentration of steviosides, although proper nitrogen fertilisation can improve various characteristics of the grown plants. The addition of 100 kg or 150 kg of nitrogen per hectare of the field in the form of urea or ammonium nitrate increased the yield of the stevia plants. The stevioside content can be increased by applying fertilisation using 100 kg or 150 kg of nitrogen per hectare in the form of ammonium sulfate. The total yield of the stevia plants grown in Poland was lower than the yield typically recorded in warmer countries, and the low concentration of steviosides in the plant suggests that more research about growing Stevia rebaudiana in Poland would be needed to develop profitable methods of stevia cultivation.
Assuntos
Fertilizantes , Nitrogênio , Stevia , Stevia/química , Stevia/crescimento & desenvolvimento , Polônia , Nitrogênio/análise , Fertilizantes/análise , Diterpenos do Tipo Caurano/análise , Diterpenos do Tipo Caurano/química , Glucosídeos/análise , Glucosídeos/química , Nitratos/análise , Nitratos/químicaRESUMO
Rebaudioside (Reb) M is an important sweetener with high sweetness, but its low content in Stevia rebaudiana and low catalytic capacity of the glycosyltransferases in heterologous microorganisms limit its production. In order to improve the catalytic efficiency of the conversion of stevioside to Reb M by Saccharomyces cerevisiae, several key issues must be resolved including knocking out endogenous hydrolases, enhancing glycosylation, and extending the enzyme catalytic process. Herein, endogenous glycosyl hydrolase SCW2 was knocked out in S. cerevisiae. The glycosylation process was enhanced by screening glycosyltransferases, and UGT91D2 from S. rebaudiana was identified as the optimum glycosyltransferase. The UDP-glucose supply was enhanced by overexpressing UGP1, and co-expressing UGT91D2 and UGT76G1 achieved efficient conversion of stevioside to Reb M. In order to extend the catalytic process, the silencing information regulator 2 (SIR2) which can prolong the growth cycle of S. cerevisiae was introduced. Finally, combining these modifications produced 12.5 g/L Reb M and the yield reached 77.9% in a 5 L bioreactor with 10.0 g/L stevioside, the highest titer from steviol glycosides to Reb M reported to date. The engineered strain could facilitate the industrial production of Reb M, and the strategies provide references for the production of steviol glycosides.
Assuntos
Diterpenos do Tipo Caurano , Stevia , Trissacarídeos , Saccharomyces cerevisiae/genética , Difosfato de Uridina , Hidrolases , Glucosídeos , Glicosiltransferases/genética , Glicosídeos , Folhas de PlantaRESUMO
Steviosides extracted from the leaves of the plant Stevia rebaudiana are increasingly used in the food industry as natural low-calorie sweeteners. Phthalates in food are often assumed to arise from food containers or packaging materials. Here, experiments were carried out to identify the potential sources of DMP, DBP, DIBP, and DEHP in the leaves of stevioside through investigation of their content in native stevioside tissues, soils, and associated agronomic materials. The results show that phthalate contamination was present in all the samples tested, and the influence of regional factors at the provincial level on the content of plasticizers in stevia leaves was not significant. Phthalates in stevia leaves can be absorbed into the plant body through leaves and roots. Using resin removal, the phthalate content in stevioside glycosides was reduced to less than 0.05 ppm, and some indicators were far lower than the limit standard in EU food.
Assuntos
Diterpenos do Tipo Caurano , Glucosídeos , Ácidos Ftálicos , Stevia , Tecnologia , EdulcorantesRESUMO
This study investigated the influence of substituting 60, 80, and 100% of the sugar in traditional cocoa hazelnut paste (control) formulation with inulin-stevia (90:10, w/w) mixture on textural and rheological characteristics, melting behavior, water activity (aw), particle size distribution (PSD), and color. Textural, rheological, melting properties, and color of samples were analyzed after 1, 2, and 3 months of storage at 11°C. Nuclear magnetic resonance (NMR) relaxometry experiments were also performed to understand the interaction of new ingredients with oil. Replacement of sugar with inulin-stevia gave darker color, reduced Casson yield stress, and changed the textural parameters and melting profile of the samples depending on the level but did not create a remarkable effect on PSD and Casson plastic viscosity. Increasing inulin-stevia content yielded lower aw and higher T2a values indicating decreased mobility of water. Complete removal of sugar caused low spreadability. The results showed that an 80% replacement level yielded a product with similar textural parameters and fat-melting mouth feeling compared to control sample. Cocoa hazelnut spreads prepared with inulin and stevia showed good textural stability during storage.