Improving gut functions and egg nutrition with stevia residue in laying hens.

This study aimed to investigate the effect of stevia residue (STER) on the production performance, egg quality and nutrition, antioxidant ability, immune responses, gut morphology and microbiota of laying hens during the peak laying period. A total of 270 Yikoujingfen NO. 8 laying hens (35 wk of age) were randomly divided into 5 treatments. The control group fed a basal diet and groups supplemented with 2, 4, 6, and 8% STER. The results showed that STER significantly increased egg production, the content of amino acids (alanine, proline, valine, ornithine, asparagine, aspartic acid, and cysteine) in egg whites, and decreased the yolk color (P < 0.05). Additionally, STER significantly increased acetate, HOMOγ linolenic acid and cis-13, 16-docosadienoic acid levels in egg yolk (P < 0.05). IL-2, IL-4, and IL-10 levels in serum significantly increased by STER (P < 0.05), while IL-1ß significantly decreased (P < 0.05). STER also increased total antioxidant activity (T-AOC) in the liver and estradiol level in the oviduct (P < 0.05), but decreased the cortisol level in the oviduct (P < 0.05). For the intestinal morphology, the jejunal villus height and crypt-to-villus (V:C) significantly increased by STER (P < 0.05). STER increased the relative abundance of Actinobacteriota (P < 0.05), while deceased Proteobacteria, Desulfobacterota, and Synergistota (P < 0.05). In conclusion, STER improved egg production, quality and nutrition, improved the immune responses, antioxidant capabilities, estrogen level, gut morphology, and increased the relative abundance of beneficial bacteria while decreased the harmful bacteria. Among all treatments, 4 and 6% STER supplementation yielded the most favorable results in terms of enhancing production performance, egg nutrition, gut health, and immune capabilities in laying hens.

Genome-wide transcriptional profiling and physiological investigation elucidating the molecular mechanism of multiple abiotic stress response in Stevia rebaudiana Bertoni.

Considering the major source of plant-derived low/non-calorie steviol glycosides (SGs), comprehensive physiological, biochemical, and deep transcriptional investigations were conducted to explicit deeper insight into multiple abiotic stress responses in Stevia rebaudiana. The physiological indicators including photosynthesis, chlorophyll, relative water content, shoot growth, electrolyte leakage, and SG biosynthesis were negatively impacted under drought (DS), followed by salinity (SS) and waterlogging (WS). Global transcriptional analysis revealed significant upregulated expression of the genes encoding for ROS detoxification (GST, SOD, APX, glutathione peroxidase), osmotic adjustment (alpha-trehalose-phosphate and S-adenosylmethionine decarboxylase), ion transporters (CAX, NHX, CNGS, VPPase, VATPase), water channel (PIP1, TIP) and abiotic stress-responsive candidate genes (LEA, HSPs, and Dehydrins) regulating abiotic stress response in S. rebaudiana. These inferences were complemented with predicted interactome network that revealed regulation of energy metabolism by key stress-responsive genes (GST, HKT1, MAPKs, P5CSs, PIP), transcription factors (HSFA2, DREB1A, DREB2A), and abiotic stress responsive pathways (ABA, ethylene, ion stress). This is the first detailed study to comprehend the molecular regulation of stress response and their interplay under DS, SS, and WS. The key genes and regulators can be functionally validated, and will facilitate targeted gene editing for genetic improvement of crop sustainability under changing environmental conditions in S. rebaudiana.

Anti-inflammatory potential of stevia residue extract against uric acid-associated renal injury in mice.

Abnormal uric acid level result in the development of hyperuricemia and hallmark of various diseases, including renal injury, gout, cardiovascular disorders, and non-alcoholic fatty liver. This study was designed to explore the anti-inflammatory potential of stevia residue extract (STR) against hyperuricemia-associated renal injury in mice. The results revealed that STR at dosages of 150 and 300 mg/kg bw and allopurinol markedly modulated serum uric acid, blood urea nitrogen, and creatinine in hyperuricemic mice. Serum and renal cytokine levels (IL-18, IL-6, IL-1Β, and TNF-α) were also restored by STR treatments. Furthermore, mRNA and immunohistochemistry (IHC) analysis revealed that STR ameliorates UA (uric acid)-associated renal inflammation, fibrosis, and EMT (epithelial-mesenchymal transition) via MMPS (matrix metalloproteinases), inhibiting NF-κB/NLRP3 activation by the AMPK/SIRT1 pathway and modulating the JAK2-STAT3 and Nrf2 signaling pathways. In summary, the present study provided experimental evidence that STR is an ideal candidate for the treatment of hyperuricemia-mediated renal inflammation. PRACTICAL APPLICATIONS: The higher uric acid results in hyperuricemia and gout. The available options for the treatment of hyperuricemia and gout are the use of allopurinol, and colchicine drugs, etc. These drugs possess several undesirable side effect. The polyphenolic compounds are abundantly present in plants, for example, stevia residue extract (STR) exert a positive effect on human health. From this study results, we can recommend that polyphenolic compounds enrich STR could be applied to develop treatment options for the treatment of hyperuricemia and gout.

Lower ΔFosB expression in the dopaminergic system after stevia consumption in rats housed under environmental enrichment conditions.

Environmental enrichment (EE) has been proven to reduce drug seeking and the development of addiction-related behaviors in rodent models, but the effects of EE on natural reward acquisition in the form of sweet beverages are poorly understood. Accumulating evidence shows that the intake of sugar, the main ingredient of sweet beverages, alters the dopaminergic system, leading to addiction-related physiological and molecular changes. Sugar in sweet beverages has been replaced with natural sweeteners, such as stevia extract, which has greater sweetener potential but no energy content. Our research group found that sucralose consumption increased the expression of ΔFosB in reward-related nuclei, suggesting activation of the dopaminergic system. The present study assessed the effects of EE on stevia consumption and the expression of ΔFosB in the nucleus accumbens, caudate putamen, and prefrontal cortex. Sixteen male Wistar rats, 21 days old, were randomly assigned to an EE group (n = 8) or standard environment (SE) group (n = 8) and reared for 30 days. On postnatal day 52 (PND52), the brains of four animals in each housing condition were extracted to determine basal ΔFosB levels. Stevia consumption with intermittent access and ΔFosB immunoreactivity were measured for 21 days in the remainder of the rats. Compared with SE animals, EE animals exhibited a reduction of stevia consumption and alterations of ΔFosB immunoreactivity in the reward system. These results indicate that EE reduces stevia consumption and the stevia-induced ΔFosB expression, suggesting addiction-related changes in dopaminergic nuclei, which may be interpreted as a neuroprotective effect.

Phytogenic Synthesis of Pd-Ag/rGO Nanostructures Using Stevia Leaf Extract for Photocatalytic H2 Production and Antibacterial Studies.

Continuously increasing energy demand and growing concern about energy resources has attracted much research in the field of clean and sustainable energy sources. In this context, zero-emission fuels are required for energy production to reduce the usage of fossil fuel resources. Here, we present the synthesis of Pd-Ag-decorated reduced graphene oxide (rGO) nanostructures using a green chemical approach with stevia extract for hydrogen production and antibacterial studies under light irradiation. Moreover, bimetallic nanostructures are potentially lime lighted due to their synergetic effect in both scientific and technical aspects. Structural characteristics such as crystal structure and morphological features of the synthesized nanostructures were analyzed using X-ray diffraction and transmission electron microscopy. Analysis of elemental composition and oxidation states was carried out by X-ray photoelectron spectroscopy. Optical characteristics of the biosynthesized nanostructures were obtained by UV-Vis absorption spectroscopy, and Fourier transform infrared spectroscopy was used to investigate possible functional groups that act as reducing and capping agents. The antimicrobial activity of the biosynthesized Pd-Ag-decorated rGO nanostructures was excellent, inactivating 96% of Escherichia coli cells during experiments over 150 min under visible light irradiation. Hence, these biosynthesized Pd-Ag-decorated rGO nanostructures can be utilized for alternative nanomaterial-based drug development in the future.

The SrWRKY71 transcription factor negatively regulates SrUGT76G1 expression in Stevia rebaudiana.

SrUGT76G1 is vital for the biosynthesis of rebaudioside A, D and M in Stevia rebaudiana Bertoni; however, its transcriptional regulatory mechanism remains unknown. In this study, the 2050-bp promoter region of SrUGT76G1 was isolated by the TAIL-PCR method, and sequence analysis revealed the presence of several W-box cis-elements, which are the recognition motifs of WRKY transcription factors. Furthermore, SrWRKY71, characterized by a typical WRKY domain and a C2H2 zinc finger-like motif, was identified as a putative transcriptional regulator of SrUGT76G1. The transcript of SrWRKY71 predominantly accumulated in leaves and was present at a lower level in stems, roots and flowers. The SrWRKY71-GFP fusion protein was specifically localized to the nucleus in tobacco epidermal cells. In addition, the N and C terminal regions of SrWRKY71 contributed to its transactivation activity. Y1H and EMSA assays validated that SrWRKY71 binds directly to W-box1 and W-box2 in the proximal promoter region of SrUGT76G1. Moreover, SrWRKY71 represses the expression level of SrUGT76G1 in both tobacco leaves and stevia callus. Taken together, the data in this study represent the first identification of an essential upstream transcription factor of SrUGT76G1 and provides new insight into the regulatory network of steviol glycoside biosynthesis in Stevia rebaudiana.

A comparative morphological and transcriptomic study on autotetraploid Stevia rebaudiana (bertoni) and its diploid.

Stevia rebaudiana is an important medical plant for producing steviol glycosides (SGs) or stevioside. Autotetraploids (4x = 44) show an increasing level of morphology, physiology and tolerances comparing to diploids (2x = 22). However, little information regarded on the comparative transcriptome analysis between diploid and autotetraploid S. rebaudiana was found. In this study, synthetic autotetraploid was induced and morphological features were confirmed. A comprehensive transcriptome of stevia leaf, stem and root from the diploids and autotetraploids was constructed based on RNA-seq, yielded 1,000,892,422 raw reads and subsequently assembled into 251,455 transcripts, corresponded to 146,130 genes. Pairwise comparisons of the six leaf libraries between the diploids and autotetraploids revealed 4114 differentially expression genes (DEGs), in which 2105 (51.17%) were up-regulated in autotetraploids and associated with SGs biosynthesis, plant growth and secondary metabolism. Moreover, weighted gene co-expression network analysis showed co-expressed genes of fifteen genes of SG biosynthesis pathway were enriched in photosynthesis, flavonoid and secondary metabolic process, plant growth and morphogenesis. A hundred of DEGs related to plant resistance were identified by interviewing PlantPReS database. This study has highlighted molecular changes related to SGs metabolism of polyploidy, and advanced our understanding in plant resistance responsible for phenotypic change of autotetraploids.

First insights into salt tolerance improvement of Stevia by plant growth-promoting Streptomyces species.

The present study aimed to investigate the potential of plant growth-promoting rhizobacteria (PGPR) to improve the salt stress and alleviate its impact on Stevia crop plant under different levels of salt concentration. Two Streptomyces spp. isolated from the rhizosphere of halophytic plants (Cucumis sativus L. and Salicornia europaea L.) have shown potential for plant growth promotion in Stevia plant. The streptomycetes isolates were identified by classical microbiological techniques and partial sequencing of 16S rRNA gene as Streptomyces variabilis (4NC) and S. fradiae (8PK). The results have shown that inoculation of Stevia plant by these isolates has enhanced plant growth parameters under applied salt stress. Moreover, total cellular proteins were extracted from the two Streptomyces isolates and SDS-PAGE technique was conducted. Mass spectrometric analysis has identified unique polypeptide of the elongation factor thermos unstable (EF-Tu) indicating the elevation of ribosomal RNA and ribosomal protein genes transcription. On the same context, alleviation of salt stress in Stevia plants inoculated with the two Streptomyces isolates has potentially promoted the accumulation of the major pronounced RuBisCO large subunit protein band detected approximately at 53 kDa. These results may give novel insights and accretion our understanding of salinity tolerance mechanisms using PGP streptomycetes to develop resistant sugar crops of highly important economic value. This study has presented the integration of microbiological, biochemical, and molecular techniques to evaluate the effect of salt stress and to assess the level of stress amelioration using PGPR on proteostasis of sugar crops in Egypt.

The impact of three commercial sweeteners on cytokine expression by mononuclears impelled by colon carcinoma cells.

The study was designed to examine the immunomodulatory effect of three commercial sweeteners on human peripheral blood mononuclear cells (PBMC) and on the immune dialogue between these and human HT-29 and HuCC colon cancer lines. PBMC were incubated with Sweet'N Low, Splenda and Stevia and the cytokine production was examined. The cytokine release of PBMC co-cultured with colon cancer cells in the presence of sweeteners was evaluated. Sweet'N Low enhanced IFNγ, IL-1ß and IL-6 release, and augmented HuCC-induced IL-10 secretion. Splenda reduced IFNγ and TNFα secretion by LPS and HuCC stimulated PBMC and enhanced HuCC-induced IL-10 and IL-1ra production. Stevia reduced IL-1ß, TNFα and IL-1ra secretion prompted by HuCC and HT-29 cells and enhanced IL-6 production induced by HuCC. The inhibition of pro-inflammatory- and increased anti-inflammatory cytokines release by Splenda and Stevia indicate that they possess valuable potential as carcinopreventive agents.

Encapsulation of stevia rebaudiana Bertoni aqueous crude extracts by ionic gelation - Effects of alginate blends and gelling solutions on the polyphenolic profile.

We formulated and characterised two alginate blends for the encapsulation of stevia extract (SE) via ionic gelation through an extrusion technique. Calcium chloride in SE and calcium chloride solutions were assessed as crosslinkers to overcome phenolic losses by diffusion and increase encapsulation efficiency (EE). Regardless of the blend, all stevia-loaded beads exhibited high EE (62.7-101.0%). The size of the beads decreased as EE increased. Fourier transform infrared analysis showed increased hydrogen bonding between SE and alginates, confirming the successful incorporation of SE within the matrix. Untargeted metabolomics profiling identified 479 free and encapsulated polyphenolic compounds. Flavonoids (catechin and luteolin equivalents) were predominant in SE whereas tyrosols and 5-pentadecylresorcinol equivalents were predominant in all bead formulations. Three-common discriminant compounds were exclusive to each blend and were inversely affected by the crosslinking conditions. Both alginate blends have been shown to be feasible as carrier systems of stevia extracts independent of crosslinking conditions.

Efectos de la ingesta de los edulcorantes estevia y D-tagatosa sobre el metabolismo de la glucosa, ácido úrico y apetito-saciedad / Effects of stevia and D-tagatose sweeteners intake om glucose, uric acid metabolism and appetite-satiety

INTRODUCCIÓN: Si bien, los edulcorantes no nutritivos (ENN) estevia y D-tagatosa han sido reportados como seguros, han demostrado tener algunos efectos metabólicos tras su ingesta. OBJETIVO: Describir los efectos de la ingesta de estevia y D-tagatosa sobre el metabolismo de la glucosa y ácido úrico, y del apetito-saciedad, a partir de la evidencia disponible. MÉTODOS: Revisión descriptiva. Se realizó búsqueda en PubMed utilizando los siguientes términos y palabras clave: "stevia rebaudiana", "tagatose", "D-tagatose", "blood glucose", "insulin", "metabolic processes", "uric acid", "hyperuricemia", "appetite" o "satiety". El análisis de los estudios seleccionados fue discrecional. RESULTADOS: Existen estudios que demuestran efectos beneficiosos tras el consumo de estevia o D-tagatosa sobre el control glicémico, apetito y saciedad tanto en sujetos sanos como con alteraciones en el metabolismo de la glucosa. Por otra parte, un número importante de estudios que evalúan la ingesta de estevia reportan efectos nulos sobre dichos parámetros. En relación al ácido úrico, solo un estudio en sujetos con enfermedad renal crónica reporta aumento en la concentración de ácido úrico plasmático tras la ingesta de 500 mg/día de estevia. Pocos estudios han evaluado el efecto de la ingesta de D-tagatosa sobre uricemia, en sujetos sanos y diabéticos, reportando un aumento transitorio y significativo en los niveles de ácido úrico sérico, sin embargo, no se ha logrado demostrar un efecto hiperuricémico asociado. Es importante destacar que la metodología de los estudios revisados es heterogénea, especialmente en relación al tamaño muestral, tiempo, dosis y vía de adminitración del edulcorante. CONCLUSIÓN: La ingesta de estevia y D-tagatosa ha demostrado efectos beneficiosos sobre el metabolismo de la glucosa, el apetito y la saciedad. El efecto del consumo de D-tagatosa sobre ácido úrico sérico requiere mayor evidencia para demostrar su significancia clínica.

INTRODUCTION: No-nutritive sweeteners stevia and D-tagatose have been reported as safe according to their acceptable daily intake, however, they have been shown to have metabolic effects after their ingestion. OBJECTIVE: To describe the effects of stevia and D-tagatose intake on parameters associated to glucose, uric acid metabolism and on appetite-satiety, considering the available evidence. METHODS: Descriptive review. PubMed search was carried out to identify the totality of the published articles. The following terms and key words were used: "stevia rebaudiana", "tagatose", "D-tagatose", "blood glucose", "insulin", "metabolic processes", "uric acid", "hyperuricemia", "appetite" o "satiety". The analysis of the selected studies was discretionary. RESULTS: studies have shown beneficial effects of stevia and D-tagatose consumption on glycemic control, appetite and satiety in healthy subjects as well as subjects with impairment glucose metabolism. On the other hand, a significant number of studies evaluating estevia intake report null effects on these parameters. In relation to uric acid, only one study in subjects with chronic kidney disease reported an increase in plasmatic uric acid concentration after the intake of 500 mg/day of stevia. Several studies have evaluated the effect of D-tagatose intake on plasmatic uric acid, in healthy and diabetic subjects, reporting a transient and significant increase in serum uric acid levels, however, has not been able to demonstrate an associated hyperuricemic effect. It is important to highlight that the methodology of the studies reviewed is heterogeneous, especially in relation to sample size, dose administered, time and route of exposure to the sweetener. CONCLUSION: Stevia and D-tagatose intake has shown beneficial effects on glucose metabolism, appetite and satiety. The effects of the consumption of both sweeteners on uric acid require further study to demonstrate their clinic significance.

Spectral lights trigger biomass accumulation and production of antioxidant secondary metabolites in adventitious root cultures of Stevia rebaudiana (Bert.).

Stevia rebaudiana (S. rebaudiana) is the most important therapeutic plant species and has been accepted as such worldwide. It has a tendency to accumulate steviol glycosides, which are 300 times sweeter than marketable sugar. Recently, diabetic patients commonly use this plant as a sugar substitute for sweet taste. In the present study, the effects of different spectral lights were investigated on biomass accumulation and production of secondary metabolites in adventitious root cultures of S. rebaudiana. For callus development, leaf explants were excised from seed-derived plantlets and inoculated on a Murashige and Skoog (MS) medium containing the combination of 2,4-dichlorophenoxy acetic acid (2, 4-D, 2.0mg/l) and 6-benzyladenine (BA, 2.0mg/l), while 0.5mg/l naphthalene acetic acid (NAA) was used for adventitious root culture. Adventitious root cultures were exposed to different spectral lights (blue, green, violet, red and yellow) for a 30-day period. White light was used as control. The growth kinetics was studied for 30days with 3-day intervals. In this study, the violet light showed the maximum accumulation of fresh biomass (2.495g/flask) as compared to control (1.63g/flask), while red light showed growth inhibition (1.025g/flask) as compared to control. The blue light enhanced the highest accumulation of phenolic content (TPC; 6.56mg GAE/g DW), total phenolic production (TPP; 101mg/flask) as compared to control (5.44mg GAE/g DW; 82.2mg GAE/g DW), and exhibited a strong correlation with dry biomass. Blue light also improved the accumulation of total flavonoid content (TFC; 4.33mg RE/g DW) and total flavonoid production (TFP; 65mg/flask) as compared to control. The violet light showed the highest DPPH inhibition (79.72%), while the lowest antioxidant activity was observed for control roots (73.81%). Hence, we concluded that the application of spectral lights is an auspicious strategy for the enhancement of the required antioxidant secondary metabolites in adventitious root cultures of S. rebaudiana and of other medicinal plants.

Chemical characterization and prebiotic activity of fructo-oligosaccharides from Stevia rebaudiana (Bertoni) roots and in vitro adventitious root cultures.

Stevia rebaudiana (Bertoni) is widely studied because of its foliar steviol glycosides. Fructan-type polysaccharides were recently isolated from its roots. Fructans are reserve carbohydrates that have important positive health effects and technological applications in the food industry. The objective of the present study was to isolate and characterize fructo-oligosaccharides (FOSs) from S. rebaudiana roots and in vitro adventitious root cultures and evaluate the potential prebiotic effect of these molecules. The in vitro adventitious root cultures were obtained using a roller bottle system. Chemical analyses (gas chromatography-mass spectrometry, (1)H nuclear magnetic resonance, and off-line electrospray ionization-mass spectrometry) revealed similar chemical properties of FOSs that were obtained from the different sources. The potential prebiotic effects of FOSs that were isolated from S. rebaudiana roots enhanced the growth of both bifidobacteria and lactobacilli, with strains specificity in their fermentation ability.

Effect of Nitrogen Fertilization and Harvest Time on Steviol Glycosides, Flavonoid Composition, and Antioxidant Properties in Stevia rebaudiana Bertoni.

This work investigated the effect of nitrogen fertilization and harvest time on the flavonoid composition and antioxidant properties of Stevia rebaudiana leaves. At the same time, changes in stevioside (Stev) and rebaudioside A (RebA) contents were recorded. A pot trial under open air conditions was set up, testing five N rates and three harvest times. The results showed that, by using an adequate N rate and choosing an appropriate harvest time, it was possible to significantly increase and optimize the bioactive compound levels. In particular, higher RebA, RebA/Stev ratio, total phenols and flavonoids, luteolin-7-O-glucoside, and apigenin-7-O-glucoside levels and antioxidant capacity were recorded by supplying 150 kg N ha(-1). Reduced or increased N availability in comparison with N150 had no consistent effect on Stevia phytochemicals content. Significant correlations were also found between stevioside and some of the flavonoids, indicating a possible role of flavonoids in the stevioside metabolic pathway, which deserves more investigations.

Antioxidant response of Stevia rebaudiana B. to polyethylene glycol and paclobutrazol treatments under in vitro culture.

This investigation was carried out with the aim of determining the effect of paclobutrazol (PBZ) (0 and 2 mg l(-1)) and polyethylene glycol (PEG) (0, 2, 4 and 6 % w/v of PEG 6000) treatments on antioxidant system of Stevia rebaudiana Bertoni under in vitro condition. Analysis of data showed that PEG treatment significantly increased hydrogen peroxide (H2O2) and phenolic contents, while PBZ treatment limited the effect of PEG on them. Our data revealed that PEG treatment significantly increased total antioxidant capacity, catalase (CAT), ascorbate peroxidase (APX), polyphenol oxidase (PPO) and peroxidase (POD) activity, while it inversely decreased glutathione reductase (GR) activity. The superoxide dismutase (SOD) activity was not affected by PEG treatment. PBZ treatment induced significantly higher levels of CAT and GR activity and lower levels of SOD activity in PEG-treated plants. PBZ in combination with PEG resulted in no significant difference on APX activity with PEG treatment alone. PBZ treatment prevented the effect of PEG on the PPO activity. PEG (with or without PBZ) treatment increased the ascorbate pool, whereas total glutathione level was not affected by PEG. Our finding indicated that PBZ reduced the negative effect of PEG treatment by quenching H2O2 accumulation and increasing the CAT activity. Collectively, the antioxidant capacity of S. rebaudiana in PEG treatment condition was associated with active enzymatic and non-enzymatic defence systems which partly could be improved by the PBZ treatment. In addition, a higher accumulation of phenolic compounds leads to a more potent reactive oxygen species scavenging activity in S. rebaudiana.

Stevia rebaudiana Bertoni as a source of bioactive compounds: the effect of harvest time, experimental site and crop age on steviol glycoside content and antioxidant properties.

BACKGROUND: This study was aimed at identifying the effect of harvest time, experimental site and crop age on the no-calorie sweetener steviol glycosides (SG) and on the antioxidant properties of stevia leaf extracts. The experiment was conducted over two growing seasons at two sites in the northeastern plain of Italy. RESULTS: The results showed that all analysed factors played an important role in defining the SG profile and the antioxidant properties of stevia extracts. A high level of phenols (78.24 mg GAE g⁻¹ DW by Folin-Ciocalteu method) and high antioxidant activity (812.6 µmol Fe²âº g⁻¹ DW by FRAP assay) were observed. The inhibition of DPPH free radicals was evaluated and an IC50 mean value of 250 µg mL⁻¹ was obtained. Significant relationships among the total antioxidant capacity and the analysed compounds were found. CONCLUSION: The results showed the possibility of obtaining, in the tested environments, very high SG yields thanks to the long-day conditions during the spring/summer season. The harvest time played a key role in determining the stevia quality, influencing the rebaudioside A/stevioside ratio. The strong antioxidant properties make very interesting the possibility of using stevia extracts to improve functional food properties.