Search

Stevia rebaudiana boasts a wide range of medical and food applications and contains polysaccharides that exert beneficial effects against oxidative stress. In this study, we optimised the extraction of a polysaccharide (SRRP) from S. rebaudiana roots by employing a Box–Behnken design and response surface methodology. The optimal extraction conditions were as follows: 93.57 min, 71.67 °C, and a water-to-raw material ratio of 21.40 mL/g. Under these conditions, 14.00 ± 0.35% of crude polysaccharide was obtained. Treatment of RAW264.7 cells with SRRP prior to the addition of H2O2, a major contributor to oxidative damage, significantly increased cell viability. In addition, SRRP increased the levels of superoxide dismutase, catalase, and glutathione and reduced the levels of malondialdehyde in RAW264.7 cells. Therefore, SRRP can provide effective protection against H2O2-induced oxidative damage. These findings indicate the potential of SRRP as a natural antioxidant in the food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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). 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. 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. 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. [ABSTRACT FROM AUTHOR]

The relationship between excessive sugar consumption and many diseases such as dental caries, obesity, diabetes and coronary heart has been increasing in recent years. In this study, utilization of natural sugar replacer steviol glycosides and bifidogenic effect by Bifidobacterium animalis subsp. lactis was assayed in vitro model system. The basal medium (non-carbohydrate containing MRS, Man, Rogosa and Sharpe Agar) were supplemented with 0.025% and 1% stevia, 0.025% stevia + 1% inulin, %1 stevia + 1% inulin. The medium which contained no carbohydrate was designated as negative control, whereas the medium containing 1% glucose or inulin were evaluated as positive and evaluated on the 0, 12, 24, 36 and 48 h of fermentation. Steviol glycosides in both system significantly stimulated the growth of Bifidobacterium animalis subsp. lactis to varying degrees with highest prebiotic activity score, short chain fatty acid production and growth parameters as much as glucose and prebiotic inulin. The viability of the probiotic bacteria was determined within the bio-therapeutic level with potential prebiotic effects depending on the probiotic bacterial strain growing and the type of carbohydrate source utilized. In the study, stevia at lower concentration showed a higher growth rate of with inulin. In conclusion, stevia can be used as functional ingredients for the modulation of the gut microbiota and design of synbiotic systems as a prebiotic substrate and sugar substitute. [ABSTRACT FROM AUTHOR]

In this investigation, the drying of Stevia rebaudiana leaves was carried out in a lab scale convective hot-air dryer at a varying temperature of 30–80°C to analyze the drying behavior, fit mathematical, Artificial Neural Networks (ANNs), and Adaptive Neuro-Fuzzy System (ANFIS) models to predict the drying kinetics of leaves. Further, dried leaf powders were analyzed for color properties, ascorbic acid and total phenol contents, antioxidant activity, water activity (aw), water solubility index (WSI), hygroscopicity (HG), density (bulk, tapped, and particle), bulk porosity, and flowability indices (Hausner ratio (HR), Carr index (CI), and angle of repose (α)). The results showed that ANFIS model with R2 of 0.9998, offers a more accurate forecast of the drying kinetics of leaves dried in a convective hot-air dryer in comparison to mathematical and ANN modeling. The convective drying significantly (p <.05) effected the L*, a*, b*, hue angle and chroma values of dried leaves. Increase in the drying temperature from 30 to 80°C resulted in a decrement of 50.90% in aw, 10.10% in tapped density, while enhancement of 23.26% in WSI, 32.93% in HG, 54% in particle density, and 10.59% in bulk porosity of dried leaf powder. Notably, ascorbic acid and antioxidant activity decreased with rising temperatures, while total phenols enhanced up to 50°C. The bulk density of dried samples remained largely unchanged with increasing temperature, while the flowability of the Stevia powder improved. Thus, these findings provide valuable insights for producers regarding the drying characteristics and properties of Stevia leaf powder. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicle (UAV) based remote sensing is one of the modern techniques for crop management, which has been used in this study for biomass and Nitrogen (N) level estimations for Stevia rebaudiana, a medicinal crop used as an alternative to sugar as a natural sweetener. Different levels of nitrogen treatments were given to S. rebaudiana and the crops were harvested for biomass estimation. Mica sense Altum multispectral sensor on board was used for acquiring the image data of the crop. The linear regression model was used to examine the best vegetation index using K-fold cross validation approach. Excess Green Index (ExG) was identified as best vegetation index for biomass estimation (R2 = 0.7; RMSE = 23.77 g/m2; nRMSE = 29.14%), whereas Enhanced Normalized Difference Vegetation Index (ENDVI) was found as best predictor for Nitrogen (N) level estimation (R2 = 0.9; RMSE = 1.75 g/m2; nRMSE = 14.59%). [ABSTRACT FROM AUTHOR]

Stevioside is the major component of Stevia rebaudiana (Bertoni) leaves, family Asteraceae. UPLC-ESI-MS/MS analyses of leaves total methanol extract (TEx) and standardized butanol fraction (BF, 113.5 mg stevioside/g) were performed herein, revealing steviol glycosides, caffeoylquinic acid derivatives, flavonoids, and sesquiterpenoids. Their hepatoprotective activities against radiation-induced toxicity were evaluated compared to pure stevioside. Rats pretreatment with stevioside, TEx, and BF orally for 7 days before subjection to 6.5 Gy whole-body-gamma-irradiation reversed histopathological damages; improved liver functions and restored depleted antioxidants. ALT and reduced-glutathione levels showed insignificant changes, compared to control, by (5.22%, 3.20%, 24.90%) and (−0.47%, −3.95%, −2.63%), respectively. Glutathione-S-transferase, catalase, and MDA levels were significantly ameliorated. Liver tissue molecular profiling showed reduction in elevated TNF-α by 23.83%, 29.06%, 28.34%, respectively, and in NF-kB and COX-2 expression levels via immunohistochemical study. BF showed better hepatoprotective activity than TEx which may be attributed to higher stevioside, flavonoids, and caffeoylquinic acid derivatives content. [ABSTRACT FROM AUTHOR]

Stevia (Stevia rebaudiana Bertoni) is a medicinal plant whose leaves are used as a natural sweetener. This study was carried out to determine the agronomic performances, yield, and macro-micronutrients in the leaves of the plant under semi-arid conditions. For this purpose, field experiments were conducted in four different locations (Kahta, Menderes, Hasancık and ADYÜTAYAM) of Adıyaman province which is located in the Southeastern Anatolia Region of Turkey. 0.5 ha of land was prepared for each location. Plots were created as three replicates and the seedlings were transplanted in 70 cm × 33 cm row distances. Plants were harvested 2 times in one growing season. Fresh and dry herb yields in the first harvest were measured as 13,949.5 and 3900.3 kg ha−1, respectively, and at the second harvest as 6923.5 and 1920.6 kg ha−1, respectively, from Menderes location. Something similar happened with regards to the ratio of leaves per plant. The K and Mn contents of leaves were not found to be statistically different. With regards to the macro and micro-nutrients measured in stevia leaves, N (2.29–3.40%) and P (0.20–0.31%), Zn (21.4–44.7 mg kg−1), Cu (13.8–34.5 mg kg−1) and Fe (204.1–446.9 mg kg−1) values were found to be statistically significant. These nutrients were affected by location and harvesting time. TSG, Reb A and Stevioside contents in stevia leaves were measured as 10.93%, 4.73% and 4.95%, respectively. The results are similar to the values specified for Criolla variety. Considering the data obtained from the study locations, it was observed that stevia can be grown easily in semi-arid conditions. It is also concluded that at least two harvests can be taken in semi-arid conditions. [ABSTRACT FROM AUTHOR]

Steviol glycosides (SGs), as natural sweeteners from Stevia rebaudiana, are currently employed for replacing sugar and its derivatives in several food products and formulations. Such compounds play an essential role in human health. Their usage provides a positive effect on preventing diseases related to sugar consumption, including diabetes mellitus, cancer, and lipid metabolism disorders. The traditional extraction of SGs is performed by means of solvent extraction, which limits their application since the removal of residual solvents is a challenging task requiring further downstream purification steps. In addition, the presence of residual solvents negatively affects the quality of such compounds. Today, food technicians are looking for innovative and improved techniques for the extraction, recovery and purification of SGs. Membrane-based technologies, including microfiltration, ultrafiltration, and nanofiltration, have long been proven to be a valid alternative for efficient extraction and purification of several high added-value molecules from natural sources. Such processes and their possible coupling in integrated membrane systems have been successfully involved in recovery protocols of several compounds, such as metabolites, polyphenols, anthocyanins, natural pigments, proteins, from different sources (e.g., agro-food wastes, plant extracts, fruits, fermentation broths, among others). Herein, we aim to review the current progresses and developments about the extraction of SGs with membrane operations. Our attention has been paid to the latest insights in the field. Furthermore, key process parameters influencing the extraction and purification of SGs are also discussed in detail. [ABSTRACT FROM AUTHOR]

Micronutrients play a vital role in physiological processes in organism cells. In this regard, three micronutrients including Copper (Cu), Iron (Fe) and Zinc (Zn) were imposed on Stevia growth medium, to find the Stevia growth and metabolites response to these nutrients. Five levels of Zn (0, 2, 4, 6 and 8 ppm), Cu and Fe (0, 2.5, 5, 7.5 and 10 ppm) were applied in three separate experiments using pots filled with a loam soil under greenhouse conditions. The micronutrients were added to the soil when plants were transplanted into the pots. The results showed that the Cu, Fe and Zn did not significantly affect the Stevia growth while Cu and Fe varied the leaf greenness index. Despite the Stevia growth, the Stevia metabolites were significantly affected by Cu, Zn and Fe. As a general result, the steviol glycosides (SVglys) of Stevia such as stevioside (Stev), rebaudioside A (Reb A) and their ratios were positively induced by Cu, Fe and Zn, compared to the control (without Cu, Fe and Zn). However, the effects of the three micronutrients were not the same and the Stevia metabolites response to these micronutrients was clearly dependent upon their concentrations. Our results showed that although Cu, Fe and Zn did not improve the Stevia growth, they remarkably increased the sweet compound in Stevia leaves, which are suggestible for more sweet compound production in Stevia. [ABSTRACT FROM AUTHOR]

Optimization of steviol glycosides and polyphenols extraction from stevia leaves for maceration, microwave-assisted (MAE) and ultrasound-assisted (UAE) techniques were performed by investigating the effects of process variables using response surface methodology. Optimum extraction conditions for maceration were 50% EtOH concentration, 118 mL/g solvent ratio, 54°C temperature, and 112 min extraction time. Optimum operation temperatures and extraction times for MAE and UAE were estimated as 51°C & 16 min and 50°C & 43 min, respectively. MAE and UAE significantly reduced processing time as compared to maceration. A total of 65 compounds were identified by LC/Q-TOF/MS analysis. [ABSTRACT FROM AUTHOR]

Agricultural production systems demand techniques that allow reducing uncertainty in decision-making. A factor that adds uncertainty in agricultural systems is altitude since it influences the nutrient uptake by plants. This work aimed to evaluate the influence of two altitudinal gradients (2569 and 1487 m.a.s.l.) and two fertilizers: an organo-mineral fertilizer (composted poultry manure mixed with inorganic fertilizer) and mineral fertilizer (control) on the nutrient uptake and biomass production in commercial stevia crops. The effect of altitude and fertilizers was evaluated after 60 days, under greenhouse conditions, assessing macro and micronutrient levels in the plant leaves (nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, manganese, zinc, iron, and boron) and biomass production. The results of this work showed the effect of altitude (2569 m.a.s.l.) and organo-mineral fertilization on crop productivity and yield. The application of the organo-mineral fertilizer decreased the differences of nutrient uptake between the altitudinal gradients and provided both better nutrient uptake levels, mainly of N (79%), Ca (115%), and Mg (162%), and increased biomass production (49%), than mineral fertilization at both experimental sites. Likewise, the organo-mineral fertilizer enhanced the soils' cation exchange capacity, increased nutrient availability, and minimizing the risks of contamination by nutrient leaching. An important conclusion of this work is that stevia plants grown at different altitudes differ in nutrient uptake (mostly nitrogen 79%); therefore, fertilizer dosing must be adjusted to crop altitude, especially for mineral fertilizers. Thus, fertilizer design should consider not only the plant nutrition requirements but also its environmental conditions. [ABSTRACT FROM AUTHOR]

The use of non-dairy matrices for probiotic delivery can be beneficial for vegetarian, vegan and lactose intolerant consumers. Stevia rebaudiana extract can be used as sweetener to replace sucrose for glucose intolerants. This research evaluated the use of kefir grains to prepare a low-calorie, fruit-based kefir beverage. Fermentation was carried out by inoculating kefir grains into a mixture of mango and umbu pulps. Two beverages, one containing sucrose, and the other, stevia, were characterized according to their proximate composition and submitted to a 30-day shelf-life period at 5°C, evaluating lactic acid bacteria, yeasts, pH, acidity, color parameters, soluble solids, ascorbic acid, sensory acceptance, and purchase intention every 10 days. Lactic and acetic acids were analyzed at the beginning and end of the shelf-life. Both beverages showed probiotic potential. The stevia-sweetened beverage had lower calorie content and good sensory acceptance. These results support the possibility to develop low-calorie, fruit-based kefir beverages. [ABSTRACT FROM AUTHOR]

The antiviral potential of natural polysaccharide compounds has been demonstrated, especially against enveloped viruses and members of the Herpesviridae family. Two polysaccharide fractions obtained from Stevia rebaudiana (Bertoni) leaves, that were active against Herpes simplex virus type 1 (HSV-1) were studied to investigate their mode of action. Both polysaccharides - SFW (crude faction) and SSFK (homogeneous alkaline fraction) - exerted antiviral effects on the initial stages of HSV-1 infection by inhibiting viral adsorption and penetration. When added after virus internalization, both fractions decreased plaque size. The effect of the fractions was confirmed by investigating viral glycoprotein expression. Based on the mode of action of the polysaccharides demonstrated in the present work and on their selectivity index, the polysaccharides obtained from S. rebaudiana could be an alternative treatment of infections caused by HSV-1. [ABSTRACT FROM AUTHOR]

Inflammation plays a major role in etiology of multiple diseases and it has become an imperative therapeutic target in pharmacological interventions. Over the years, natural products originating from plants have made great contributions in the drug discovery process. Belonging to the Asteraceae family, Stevia rebaudiana (S. rebaudiana) is exploited at a large scale for its purpose as a natural sweetener. Even so, researchers have begun to notice other bioactive potential use of stevia such as anti-inflammatory and anti-cancer activities, which are conferred by compounds present in the leaves including stevioside, rebaudioside and isosteviol. In this review, we provide a brief overview of S. rebaudiana plant and its bioactive compounds and highlight their anti-inflammatory potential for therapeutic applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of thermal processing on physicochemical properties, steviol glycosides, bioactive compounds, and antioxidant capacity degradation of a beverage based on exotic fruit juices, orange juice, açaí, and oat and sweetened with Stevia rebaudiana water extracts at different concentrations. The experimental design comprised a response surface methodology according to a central composite face-centered design. The variable ranges were 60-99°C, 0.25-15 min, 0-2.5% Stevia percentage. This design was used to determine the optimal thermal processing-Stevia concentration in order to obtain the best retention of bioactive compounds and physicochemical properties in the beverage following thermal processing. Thermal processing conducted in the sample containing 2.5% Stevia at 82.4°C for 3.8 min led to the beverage with the greatest presence of antioxidant compounds. The evaluation of the thermal processing critical parameters on antioxidant compounds can contribute to achieve optimal processing conditions in order to obtain new beverages with high antioxidant potential. [ABSTRACT FROM AUTHOR]

A silica gel orthogonal method using acetonitrile: water was developed for the analyses of fractions rich in very polar steviol glycosides and resolve regions of co-elution of these compounds in reversed-phase. Additionally, we also used this normal phase analytical method to scale up the purification process of steviol glycosides. Using these approaches, one novel minor tetra-glucopyranosyl diterpene glycosides together with three known compounds were purified from a commercial Stevia rebaudiana leaf extract. Compound 1 was unambiguously elucidated as 13-[(2-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy]ent-kaur-16-en-19-oic acid-(6-O-β-D-glucopyranosyl-β-D-glucopyranosyl) ester (rebaudioside Y) based on high-performance liquid chromatography retention times, tandem mass spectrometry dissociation pattern and 1D and 2D NMR experiments. Known compounds were isolated in gram quantities and identified as rebaudioside D, E and M. [ABSTRACT FROM AUTHOR]

Light and temperature are among the environmental factors affecting germination of seeds and seedling growth. Therefore, this experiment was carried out to evaluate the effect of light (light, dark, and combined light and dark) and temperature (15, 20, 25, and 30 °C) treatments on seed germination indices and physiological traits of stevia. With increasing temperature to 25 °C, percentage and rate of germination, seedling length, and vigor index increased. Also, dark and integrated treatments light and dark conditions caused increased all traits, except for the mean germination time. The highest proline and protein contents were achieved under light conditions at 15 and 30 °C, respectively. With increasing temperature, the activity of antioxidant enzymes catalase and superoxide dismutase increased. The highest activities of catalase and superoxide dismutase were observed under light condition. In contrary, the highest peroxidase activity was observed under dark condition. Overall, the results showed that dark and combined dark and light conditions at 25 °C improved the physiological characteristics of the plant that can increase germination indices. [ABSTRACT FROM AUTHOR]

Stevia (Stevia rebaudiana) is an emerging perennial crop in the southeastern United States. A Septoria leaf spot disease of stevia was first identified on field plantings in Japan in 1978. The pathogen was named Septoria steviae based on a morphological characterization. In 2015, a species of Septoria with morphological characters of S. steviae was isolated from field and greenhouse-grown stevia plants with leaf spot symptoms in North Carolina. In this study, 12 isolates obtained from diseased stevia plants in 2015 and 2016 were characterized and compared with reference strains of S. steviae. Comparisons were based on conidial and pycnidial morphology and multilocus sequence analysis of actin (ACT), β-tubulin (BT), calmodulin (CAL), nuc rDNA internal transcribed spacers (ITS1-5.8S-ITS2 = ITS), nuc rDNA 28S subunit (28S), RNA polymerase II second largest subunit (RPB2), and translation elongation factor-1α (TEF1). Measurements of conidia and pycnidia from symptomatic field leaves and 12 pure cultures grown on nutrient medium were consistent with those previously reported for ex-type strains of S. steviae. North Carolina strains formed a well-supported monophyletic group with ex-type strains of S. steviae. This study represents the first genetic characterization of S. steviae in the United States and provides an experimental framework to elucidate the genetic diversity and disease ecology of field populations of S. steviae. [ABSTRACT FROM AUTHOR]

Stevia rebaudiana leaves is a well-known medicinal plant for its non-caloric bio-sweetener. To enhance its value addition, employed first time for synthesis and stabilization of ZnO nanoparticles. The characterization using UV-Spec, FE-TEM, XRD, DLS revealed that SR-ZnO (ZnO particles obtained from S. rebaudiana) were flower-shape, 500–1,000 nm sizes, hydrodynamic diameter Z-average of polydisperse SR-ZnO was 582.35 ± 52.40 nm with a PDI of 0.33 ± 0.002. Furthermore, 76% degradation of methylene blue dye within 30 min exposure to SR-ZnO and plant extract under UV light indicates that it could be utilized as an efficient photocatalyst for wastewater treatment. [ABSTRACT FROM AUTHOR]

Stevia rebaudiana (Bert.) Bertoni (Asteraceae), a native to South America and now well adapted and cultivated in different parts of India. Steviosides and extracts prepared from the leaves have been used widely all over the world as sweetening-agents, taste-modifiers and sugar-substitutes. Presently a study has been undertaken to analyze chlorogenic acid in the in situ and in vitro S. rebaudiana populations. Nodal explants were raised in Murashige and Skoog media supplemented 6-benzyladenine (BA; 8.5 mM) and indole- 3-butryic acid (IBA; 9.2 mM) to achieve the best shoot-yield. Chromatographic separation was performed on silica gel 60 F254 TLC plates with toluene: ethyl acetate: formic acid (5:5:1) as mobile phase. Densitometric measurement was performed in the ultraviolet region at λ=330 nm. In vitro raised S. rebaudiana from Jalandhar district was found to contain the maximum CGA (0.077%) content and in situ grown samples from the same district showed the minimun CGA content (0.021%) whereas in situ grown plant sample collected from Lucknow district possessed 0.010% of CGA. The present investigation not only quantifies the amount of CGA present in S. rebaudiana, it also presents a simple, validated and reproducible protocol to analyze CGA in plant samples using HPTLC. [ABSTRACT FROM AUTHOR]

Stevia (Stevia rebaudiana Bertoni) is a perennial plant producing some natural sweeteners. Stevia is considered as a new crop in some countries. This study was conducted to find the stevia response to nitrogen fertilizer supply. Different levels of nitrogen (0, 30, 60, 90, 120, and 150 kg/ha from urea source) were used in a greenhouse condition and then the stevia growth and metabolites were assessed under different availability of nitrogen. Results showed that the optimum growth of stevia was obtained by 60 kg/ha nitrogen and more nitrogen supply did not enhance the stevia growth. It was observed that the total steviol glycosides (SVglys) content of Stevia was significantly increased by nitrogen fertilizer application just up to 30 kg/ha, while it decreased by more rates of nitrogen fertilizer. Our result clearly showed that SVglys yield reached to maximum value by application of 60 kg/ha of nitrogen fertilizer. Since the variation of SVglys content and shoot growth of the stevia were compromised by 60 kg/ha nitrogen, it can be concluded that 60 kg/ha of nitrogen fertilizer could be considered as an optimum rate of nitrogen for stevia and could also be recommended for greenhouse conditions. [ABSTRACT FROM AUTHOR]

In the present work, the efficiency of different nitrogen doses (0, 50, 100, 150, and 200 kg ha-1) on growth, yield, and quality of stevia (Stevia rebaudiana Bert.) was investigated in 2011-2013. The study was conducted in Antalya located in the Mediterranean Region of Turkey. Terra rossa type soil (LVx, FAO) characteristics of the experimental field were clay loam, with high amounts of lime (33,9%) and slightly alkaline (pH 7.7). The experiment was carried out in randomized block design with four replications. All the results were summarized as mean of three years. The highest fresh and dry biomass yields (26.75 t ha-1 and 7.5 ha-1, respectively) were obtained from 150 kg ha-1 N dose and followed by 100 kg ha-1 N dose (26.29 t ha-1 and 7.24 ha-1, respectively). Whereas the highest fresh and dry leaf yields (13.27 t ha-1 and 3.82 t ha-1, respectively) were realized in 100 kg ha-1 N dose. Actually, all nitrogen doses gave higher biomass and leaf yields compared to the control. On the hand, major steviol glycosides (stevioside and rebaudioside A) in the leaf were not influenced by nitrogen levels. In conclusion, 100 kg ha-1 N dose was found to be suitable for cultivation of stevia under field conditions. [ABSTRACT FROM AUTHOR]

Stevia rebaudiana Bertoni is a perennial medicinal herb indigenous to tropical regions of South America. The present study evaluated some physiological changes of the plant under cold in the absence and the presence of polyamine conditions. The results showed photosynthetic pigments and photochemical efficiency of PSII reduced in cold treatment conditions than control, significantly. However, a considerable increase in the parameters was observed in all of polyamine treated goups. Leaf compatible solutes such as proline and glycine betaine that were not shown significantly increasing at cold treatment groups, elevated in the 2 days cold-polyamine-treated group. The similar results were seen for free amino acid and total protein contents of the treated plants. It was also revealed that specific activity of some antioxidant enzymes such as catalase and ascorbate peroxidase increased in cold-treated or cold + polyamine-treated groups than related controls. It caused a significant decrease in H2O2 and malondialdehyde contents of the treated plants. The results indicated an increasing in saturated long chain fatty acids after 4 days of cold at 4 °C. It was concluded that the polyamine supplement can induced a considerable tolerance in stevia plants at cold condition. [ABSTRACT FROM AUTHOR]

Stevia (Stevia rebaudiana Bertoni) is a perennial and subshrub herb of the Asteraceae family, which originates from South America. Stevia has long been used as a sweetener and herbal medicine throughout the world. The most important feature of stevia is its sweetness with zero calories. This natural feature of Stevia is of utmost importance to everyone, especially those with diabetes and those who diet. In this study, samples were taken from Stevia rebaudiana plants of different ages (2, 3 and 4 years) in different growth periods (H1: 1 July, H2: 1 August, H3: 1 September and H4: 1 October) and an evaluation was made on the nutritional content values, the chlorophyll and sugar rates found in these samples according to the age and growth period of the plant. It was determined that the age of the plant and the harvesting period had an effect on the macro-micro nutritional elements, and chlorophyll and steviol glycoside rates contained in the stevia plant. In addition, as a result of correlation analysis, significant correlations were determined between the parameters measured in the plant. The results of the study demonstrated that in the cultivation of stevia, the best values were obtained from plants that were 3 years old and harvested in July. [ABSTRACT FROM AUTHOR]

The leaves of Stevia rebaudiana Bertoni has nutrients and phytochemicals, which make it an adequate source for the extraction and production of functional food ingredients. Preclinical and clinical studies suggest therapeutic and pharmacological applications for stevia and their extracts because they are not toxic and exhibit several biological activities. This review presents the biological activity of Stevia rebaudiana Bertoni and their relationship to antidiabetic, anticariogenic, antioxidant, hypotensive, antihypertensive, antimicrobial, anti-inflammatory and antitumor activities. Consumption and adverse effects were also reviewed. [ABSTRACT FROM AUTHOR]

With this study, the effect of different nitrogen (N) doses applied to sweet herb (0, 50, 100, 150 and 200 N kg ha−1) on the macro/micro nutrient element content, dry matter ratio and on the chlorophyll amount in the plant leaves is examined. The research was carried out in the research and trial field of Faculty of Agriculture Agronomy department, Akdeniz University, during the 2012–2013 growing season under field conditions for 2 years with four replications according to the randomized block trial design. Chlorophyll amounts were determined and the average was obtained with three readings from each leaf by a chlorophyll meter when the plants were in the beginning of flowering. Post-harvest macro and micro nutrient elements of the sweet herb were also investigated. According to the obtained data, while the highest chlorophyll and N amounts in the leaf for both the first and second years were determined as 46.97 SPAD (Minolta Corp, NJ, USA) and 1.34 N% 44.9 SPAD, 1.42 N%, respectively, under 200 kg ha−1N application, the lowest chlorophyll and N amounts were determined in the control group. In addition, N application in different doses for both years increased the phosphorus (P) and potassium (K) contents and increased the microelement contents, especially in the second year. At the same time, a correlation between the chlorophyll content in the plant leaves and the N amount was determined and a linear increase was observed in the chlorophyll amount with the increased green part. [ABSTRACT FROM PUBLISHER]

Stevia rebaudiana(Bertoni) leaves consist of stevioside and rebaudioside-A (Reb-A). This research sought to improve extraction of target steviol glycosides from stevia leaf powder using response surface methodology (RSM) and artificial neural networking (ANN) under these independent variables: ethanol concentration,X1(0–100%), extraction temperature,X2(55–75°C), and extraction time,X3(45–75 min). ANN outperformed as potential alternative to RSM in predicting optimum conditions. Maximum responses were obtained at 100%X1, 55°CX2, and 60 minX3. Heat reflux extraction proved superior to maceration extraction in terms of higher extraction yields with reduced energy consumption and CO2emission. [ABSTRACT FROM PUBLISHER]

The adaptation of stevia to the growing conditions of NE Portugal is assessed, including the tolerance of this species to cold temperatures, and the potential to produce biomass when grown as an annual crop and when subjected to various nitrogen (N) rates and two harvesting regimes. Almost all the plants died during the winter of 2014 (minimum temperatures peaked at −8.0°C), making it necessary to replant the crop the following spring. With the best cutting regime (double cut) and N rate (150 kg N ha−1), 1514.4 and 2390.0 kg ha−1of dry leaves were produced, respectively, in 2014 and 2015. Leaf chlorophyll concentrations estimated by the SPAD (Soil and Plant Analysis Development)-502 chlorophyll meter and a NDVI (Normalized Difference Vegetation Index) carried out by the Field Scout CM 1000 spectroradiometer showed significant differences among N rates, proving to be good indicators of plant N nutritional status. Based on the leaf analysis, provisional sufficiency ranges for N are proposed, namely 25–35 g kg−1for mid-summer and 15–25 g kg−1for early autumn. The fluorescence of chlorophyllaand the transient fluorescence intensity performed by the OS-30p+ fluorometer failed to show any stress induced by no-N control treatments in comparison to N-treated plants. [ABSTRACT FROM PUBLISHER]

Stevia rebaudiana(Bert.) Bertoni has sporophytic self-incompatibility and this may lead to poor seed yield and quality, which are obstacles to large-scale crop establishment. This research investigated the influence of insect pollinators and the harvesting time on the qualitative and quantitative characteristics of the ripe seeds. A pot trial under open field conditions was established to evaluate the abundance of insect pollinators and three harvesting times on the production of ripe seeds, germination percentage, mean germination time and thousand seed weight (TSW) in 36 F1 open-pollinated genotypes. Large variability in the number of corymbs of capitula, flowering time, reproductive period and seed yield was observed among the genotypes. Genotypes with promising phenological and reproductive properties were identified. The worst germination percentage and TSW were recorded in the latest harvest. Significant linear regressions were found among the investigated parameters (insect number, germination percentage, TSW, seeds yield per plant and cycle length), confirming complex interactions on the yield and quality of stevia seeds. Results indicate that earlier flowering genotypes produced higher seed quantity, due to favourable weather conditions during the reproductive phase. Moreover, cross-pollination and the insect abundance, as Apidae and Syrphidae, play a crucial role for enhancing the stevia seed yield and quality. [ABSTRACT FROM PUBLISHER]

This work investigated the agronomic, physiological and biochemical response ofStevia rebaudianaBertoni grown under different nitrogen (N) rates. A pot trial in open air conditions was set up in 2012 with the aim to evaluate the effect of four N rates on the biometric and productive characteristics, steviol glycoside (SG) content as well as on leaf gas exchanges, chlorophyll fluorescence, photosynthetic pigments, Rubisco activity and N use efficiency. N deficiency caused a decrease in leaf N content, chlorophylls and photosynthetic CO2assimilation, resulting in a lower dry matter accumulation as well as in reduced SG production. The application of 150 kg N ha− 1seems to be the most effective treatment to improve rebaudioside A (Reb A) content, Reb A/stevioside ratio, photosynthetic CO2assimilation, stomatal conductance, N use efficiency, ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) and PSII efficiency. The results demonstrate that by using an appropriate N rate it is possible to modulate the SG biosynthesis, with a significant increase in the Reb A content and in the ratio between Reb A and stevioside. This finding is of great relevance in order to obtain a raw material designed to meet consumer needs and bio-industry requirements for high-quality, Reb A content, and safe and environmentally friendly products. [ABSTRACT FROM PUBLISHER]

Stevia rebaudianaBertoni (Asteraceae) is a perennial shrub of South America, produces diterpene glycosides used as low calorie sweeteners. Stevioside and extracts prepared from the leaves have been used widely all over the world as sweetening agents, taste modifiers and sugar substitutes. Gallic acid (GA) is reported for its anti-inflammatory, anticancer, antiviral and antimelanogenic activities and many of these are mediated by its antioxidative capacity. Presently a study has been conducted on the comparative High Performance Thin Layer Chromatography (HPTLC) analysis of gallic acid from the dried leaf powder ofin-situandin-vitrogrownS. rebaudiana. Nodal explants ofS. rebaudianawere culturedin vitroin MS media supplemented with 6-benzyladenine (BA; 8.5 mM) and indole-3-butyric acid (IBA; 9.2 mM). The quantitative determination of gallic acid was performed on silica gel 60 F254 HPTLC plates as stationary phase. The linear ascending development was carried out in a twin trough glass chamber saturated with a mobile phase consisting of chloroform: ethyl acetate: formic acid (5:4:1) at room temperature (22±2°C). CAMAG TLC scanner-3 equipped with CATS software (version: 1.4.4.6337) was used for spectrodensitometric scanning and analysis in the ultraviolet region at λ=280 nm. The method was validated for linearity, precision and accuracy. Correlation coefficient, limit of detection (LOD), limit of quantification (LOQ) as well as recovery values were found to be satisfactory.S. rebaudianaraisedin vitro(0.042 %) was found to contain higher amount of GA than their naturally growing counterparts (0.022 %). [ABSTRACT FROM AUTHOR]

Wheat bread with sucrose content replaced with different levels of stevia extract was compared with traditional wheat bread. The ability to reduce glucose intake was highlighted by performing enzymatic assays using α-amylase and α-glucosidase. Antioxidant activity was measured by determining the scavenging effect on α,α-diphenyl-β-picrylhydrazyl radical. In comparison with the control, the bread with stevia extract was softer and had lower microbial growth during the shelf-life study. The sensory test showed that the substitution of 50% stevia extract was more acceptable when comparing with all the quality characteristics. Regarding the nutritional contribution, the content of dietary fiber and digestible carbohydrates in the bread with stevia extract was higher and lower respectively, so caloric intake was significantly reduced. The results showed that the biological properties ofStevia rebaudianaextract were retained after the bread making process and that the proposed bread could be suitable as functional food in human nutrition. [ABSTRACT FROM PUBLISHER]

The present work reports a method for green synthesis of silver nanoparticles (AgNPs) by reducing Ag ions from silver nitrate solution using alcoholic, aqueous and alcoholic-aqueousStevia rebaudianaextracts. Depending on a particular extract different sizes of AgNPs could be observed – 40 nm in aqueous and aqueous-alcoholic extracts and significantly bigger 170 nm in case of alcoholic extract. Synthesis of AgNPs was analyzed within spectra range of 300–700 nm. The performed research provided information that aqueous and aqueous-alcoholic extracts are excellent sources for synthesis of AgNPs; however AgNPs were unstable in the case of alcoholic extract. The aqueous-alcoholic extract showed the best properties during studies. Antioxidant potential, antimicrobial properties and cytotoxicity were determined. The 2,2-diphenyl-1-(2,4,6-triphenyl-hydrazyl) method showed that antioxidant activity of an extract containing AgNPs was higher compared to Stevia extract alone. Bacterial inhibition studies had shown substantial antibacterial properties of AgNPs, which was much higher than Stevia extract alone and silver nitrate. [ABSTRACT FROM AUTHOR]

The leaves and stems of Stevia rebaudiana produce steviol glycosides which are sweeter than sucrose, of low calorific value, pH- and heat-stable, and may have a variety of therapeutic benefits. Stevia seed germination is poor and the initial stages of growth are slow, which makes young plants susceptible to competition from weed species. In Australia, no herbicides are currently registered for use on Stevia. The purpose of this study was to assess the efficacy of 16 herbicides on S. rebaudiana and associated weeds. All 16 herbicides were trialled at their most relevant application rates at a field site in tropical Queensland. The best four performers were then tested at two rates of application at another tropical site. The post-planting, pre-weed emergence, oryzalin-containing herbicide, Prolan 500, at either 6.8 or 8.5 1 h a 1 provided the best weed control without affecting the biomass of the Stevia crop. High-performance liquid chromatography was used to determine if rebaudioside A and stevioside concentrations were affected in leaves treated with Prolan 500. It was found that at 1, 4, and 8 weeks after treatment, 8.5 1 ha'Prolan 500 resulted in significantly lower rebaudioside A and stevioside concentrations than applying Prolan 500 at 6.8 1 haA We therefore recommend that the oryzalin-containing herbicide, Prolan 500 is suitable for use on S. rebaudiana at an application rate of 6.8 1 ha-1. [ABSTRACT FROM AUTHOR]

The aim of our study was to determine the antioxidant activities, cytotoxicity and proliferative properties in Stevia rebaudiana leaves and stems. Leaves extracts exhibited a higher antioxidant activity than stems extract, through oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) assays. Stevioside and rebaudioside A, the main sweetening metabolites in stevia leaves, exhibited a low ORAC value in comparison with plant extracts, while did not elicit any CAA. Stevia rebaudiana did not exhibit toxicity against HepG2 (hepatocellular carcinoma) human cells. No proliferative nor catalase modulations were observed in cells treated with such extracts. Our findings support the promising role of stevia that, apart from its sweetness, can act as a source of antioxidants, even at the intracellular level. This activity makes S. rebaudiana crude extract an interesting resource of natural sweetness with antioxidant properties which may find numerous applications in foods and nutritional supplements industries. [ABSTRACT FROM AUTHOR]

The effects of bioorganic nutrients on stevia were studied during 2011 and 2012 at Institute of Himalayan Bioresource Technology, Palampur, India. Bioorganic nutrient sources were evaluated in fourteen treatment combinations. Results showed that number of leaves plant−1, leaf area plant−1, and fresh and dry leaf biomass plant−1were significantly greater with the application of farmyard manure (FYM) 15 Mg ha−1+ vermicompost (VC) 5 Mg ha−1 + stevia seedlings treated with phosphorus-solubilizing bacteria (PSB) and azotobacter as compared to the control but plant height and the number of branches were not significantly affected by various treatments. This superior combination also resulted in considerably greater amounts of phosphorus (P) in stem (1.18 percent) and potassium (K) in leaf (2.39 percent). Stevia plants supplied with VC 7.5 Mg ha−1 + stevia seedlings treated with PSB and azotobacter recorded greater stevioside (7.2 percent) and total steviol glycoside (8.4 percent). Application of organic manures in combination with biofertilizers enhanced soil organic carbon and available nutrient status of soil as compared to control. [ABSTRACT FROM AUTHOR]

Stevia products are advertised as a zero-calorie sweetener. Glucose should not be an intrinsic component of this product, but it has been identified from some of stevia products in a preliminary study. An UHPLC-UV method was developed for the quantitative determination of glucose from stevia products. After stevia products reacted with 1-phenyl-3-methyl-5-pyrazolone (PMP), PMP derivatives were analysed and glucose was found in seven out of 35 products in the range 0.3–91.5% (w/w). Two products, SPR-12 and SPR-27, showed remarkable amounts of glucose at 61.6% and 91.5%, respectively. In addition, an UHPLC-UV-evaporative light-scattering detector (ELSD) method was developed for the quantitative determination of rebaudioside A, stevioside, rebaudioside D, dulcoside A and steviolbioside fromSteviarebaudianaand related products. In a 12 min run, five steviol glycosides were baseline-separated. ELSD and ultraviolet (UV) detections showed comparable results. The LC methods were validated for linearity, repeatability, accuracy, limits of detection (LOD) and limits of quantification (LOQ). For steviol glycosides, the LODs and LOQs were found to be less than 10 and 30 μg ml–1, respectively. The RSD for intra- and inter-day analyses was less than 2.5%, and the recovery was 90–94%. For PMP derivative of glucose, the LOD and LOQ were 0.01 and 0.05 μg ml–1, respectively. Repeatability (RSD) was less than 2.6%; recovery was 98.6–101.7%. The methods are useful for the identification, quality assurance, and adulterant assessment ofS. rebaudianaand steviol glycosides sweeteners (stevia products). [ABSTRACT FROM PUBLISHER]

Leaf chlorophyll (Chl) content is an indicator of photosynthetic activity, stress condition and nutritional status of a plant. The efficacy of a hand-held Chl meter (CCM-200) for non-destructive estimation of total Chl and nitrogen content in the stevia (Stevia rebaudianaBertoni) leaves has been evaluated. [ABSTRACT FROM AUTHOR]

Stevia rebaudianaBertoni (Asteraceae Family), characterized by a high content of steviol glycosides (SG) in its leaves, represents an interesting source of non-sucrose and no-calorie sweeteners. Stevia, which is native to Paraguay, is a relatively new crop for the Mediterranean region, where it is grown as an annual or poly-annual crop. In order to assess the crop’s environmental requirements, productive performance and nutrient uptakes, a two-year field experiment was carried out in north-eastern Italy, where the species had never previously been cultivated. The aim was to evaluate the effects of important pre-harvest factors, such as cultivation site, harvest time and their reciprocal interaction, on productivity, leaf SG yield and nutrient requirements. Results showed that the timing of the harvest and the pedo-climatic conditions of the cultivation sites had a significant effect on the main biometric traits, total and leaf dry yield, SG production, macronutrient concentration and uptake. [ABSTRACT FROM PUBLISHER]

Stevia rebaudianaBertoni, commonly known as Stevia, is an ancient sweet herb native to Paraguay. The plant, especially the leaves, has a sweetening effect 300 times sweeter than saccharose. Malaysia has taken a particular interest in promotion of Stevia derivatives as a precautionary measure to combat chronic diseases. This study aims to investigate factors that influence the acceptance of Stevia-based products by consumers. Face-to-face interviews were conducted using a structured questionnaire with 900 consumers from Klang Valley areas. The results revealed that most of the respondents were willing to use Stevia-based products as a substitute for sugar. There was also a significant relationship between level of education and consumer’s willingness to change for Stevia-based products. Health benefits, promotion, availability, and price were found to be the most influential factors toward acceptance of Stevia-based products by consumers. An effective promotion is necessary to increase consumer’s awareness toward a more healthy diet. [ABSTRACT FROM AUTHOR]

The study of sweeteners for replacing sucrose is increasingly important for the food industry. The ideal sweetness as sucrose and the equivalent sweetness of acerola nectar with different sweeteners (neotame, sucralose, stevia with 40%, 60%, 80% and 95% rebaudioside A) were measured. The ideal sweetness of the samples sweetened with sucrose at 50 g/L, 75 g/L, 100 g/L, 125 g/L and 150 g/L was assessed by means of a test with 50 consumers using a just-about-right scale. The magnitude estimation method for determining the equivalent sweetness was carried out with 20 assessors. The concentration of sucrose ideal in acerola nectar was 80 g/L, with equivalent concentrations of sweeteners of 0.017 g/L neotame, 0.16 g/L sucralose, 1 g/L stevia with 40 % rebaudioside A, 0.99 g/L stevia with 60 % rebaudioside A, 1 g/L stevia with 80 % rebaudioside A and 1 g/L stevia with 95 % rebaudioside A. [ABSTRACT FROM AUTHOR]

Stevia rebaudianaBertoni is a plant used in the food industry as a sweetener but is also empirically used for the treatment of diabetes. The scientific literature has reported anticariogenic, antineoplastic, antihypertensive, anti-inflammatory and antihyperglycemic effects, among which the antihyperglycemic effect is the most reported. The aim of this study was to conduct a systematic review on those reported of theStevia rebaudianaextract or components for potential diabetes treatments. Studiesin vivoandin vitroindicate that the plant extract and a compound that is steviol-derived, stevioside, possess antihyperglycemic effect and their mechanisms of action is through suppression of gluconeogenesis (plant extract) and increased insulin secretion (plant extract and stevioside); rebaudioside A increases insulin secretion exclusivelyin vitroand with high concentrations of glucose. [ABSTRACT FROM AUTHOR]

Stevia rebaudiana Bertoni is a unique medicinal plant which is mostly utilized as a sugar substitute for diabetic patients. In this research, regenerated plantlets of stevia in tissue culture is transferred to pots in greenhouse and inoculated with plant-growth-promoting rhizobacteria (PGPRs) (Bacillus polymixa, Pseudomonas putida, and Azotobacter chroococcum) and arbuscular mycorrhizal fungus (AMF) (Glomus intraradices). The results showed that in comparison to control, inoculation with a single microorganism, significantly increased root and shoot biomass as well as stevioside, chlorophyll, and NPK content in plants. However, such increased effects have been found to be further enhanced significantly due to dual compatible mixtures of inoculants resulting from their strong synergistic relationships among themselves. All growth parameters recorded the highest in 60-days-old plants in the treatment of Glomus + Azotobacter and followed with Glomus + Bacillus and Azotobacter + Pseudomonas treatments, respectively. Furthermore, high-performance liquid chromatography (HPLC) chromatograms revealed that the highest stevioside content have been produced in same treatments. Triple treatments had less positive effects compared to dual inoculations. Probably competence between microorganisms in triple inoculations has reduced their efficiency. Thus, suitable combination of mycorrhizal fungi and PGPR as biotic elicitors can enhance growth and stevioside content in tissue culture-regenerated plantlets of stevia. [ABSTRACT FROM AUTHOR]

A field experiment was conducted during 2008 and 2009 at the Council of Scientific and Industrial Research-Institute of Himalayan Bioresource Technology, Palampur, India, to study the effect of organic sources of nutrient on yield, nutrient uptake, fertility status of soil, and quality of stevia crop in the western Himalayan region. The experiment comprised eight different combinations of organic manure [farmyard manure (FYM), vermicompost (VC), and apple pomace manure (AP)]. Total leaf dry biomass increased by 149% over the control with application of VC 1.5 t ha−1+ AP 5 t ha−1. Application of organic manures enhanced organic carbon and available nutrient status of soil more than the control. Nitrogen (N) and phosphorus (P) content in stem were significantly affected by the application of organic manures over the control. Stevia plants supplied with FYM 10 t ha−1+ AP 2.5 t ha−1recorded more total glycoside than other treatments. Stevioside yield (kg ha−1) was greater with application of FYM 10 t ha−1+ AP 2.5 t ha−1. [ABSTRACT FROM AUTHOR]

During 2008 and 2009, field experiments were conducted at the research farm of CSIR-Institute of Himalayan Bioresource Technology, Palampur, India to assess the effect of shade levels (no shade, 25% shade, 50% shade, 75% shade) and plant geometry levels [30 × 15 cm (north–south, N–S), 45 × 10 cm (N–S), 30 × 15 cm (east–west, E–W) and 45 × 10 cm (E–W)] on the growth, yield and quality of stevia. Plant development was fastest in controls and slowest in stevia plants growing at minimum light (75% shade). These plants showed delayed bud formation and flowering. Significantly, higher dry leaf yield was recorded when the crop was grown under 25% shading than under 50 and 75% shade. Total steviol glycosides content decreased with increasing shade levels. All shade levels resulted in the same leaf-to-stem ratio, which was significantly higher than that obtained under ambient light. Plant geometry significantly affected the number of leaves and leaf dry weight plant–1. During both years, dry leaf weight was highest in the wider row spacing (45 × 10 cm) than in the narrow row spacing (30 × 15 cm). Stevia spaced at 30 × 15 cm in an E–W direction recorded significantly higher total steviol glycosides at 2 months after transplanting (MAT). [ABSTRACT FROM AUTHOR]

Context: Stevia rebaudiana Bertoni (Asteraceae) is an important medicinal plant and is much used due to its zero calories sweetening property. Stevia leaves as well as its extracts and pure compounds are currently used in the preparation of several medicines, food products and neutraceuticals. Objective: To study the genetic and metabolic variability in S. rebaudiana among accessions of different geographical regions of India using random amplified polymorphic DNA (RAPD) markers and high-performance thin layer chromatography (HPTLC) analysis. Materials and methods: The RAPD analysis of Stevia rebaudiana (11 accessions) was carried out using 20 random operon primers. Dendrogram was constructed for cluster analysis based on the unweighted pair group method with arithmetic means (UPGMA) using Winboot. The HPTLC analysis of all samples was carried out on silica using acetone:ethyl acetate:water (5:4:1, v/v/v) for fingerprinting and quantification of stevioside and rebaudioside A at 360 nm after spraying with anisaldehyde sulphuric acid. Results: Ten out of 20 primers screened were found most informative; amplification products of the genotypes yielded a total of 87 scorable bands (67 polymorphic), whereas genetic similarity (GS) coefficient (0.01-0.08) and polymorphism (67.24-92.40%) showed huge variability. Similarly, HPTLC analysis showed large variation among different samples with respect to their presence or absence of metabolite and their concentration. Conclusion: Out of the 11 Stevia accessions, Delhi and Mohali varieties showed much relatedness with each other and were concluded to be the superior genotype in context to RAPD and HPTLC analysis. The information obtained here could be valuable for devising strategies for cultivating this medicinal plant. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the phytochemical screening of various extracts ofStevia rebaudianaleaves. Further, the alcohol and aqueous extracts were subjected to determine theirin vitroanthelmintic and antifungal activities againstP. posthumaandA. galliearthworms as well as plant pathogenic fungiB. cinereaandF. oxysporum, respectively. The alcoholic and aqueous extracts ofS. rebuadianacontained steroids, glycosides, tannis, alkaloids and saponnis like phytochemicals. Both alcoholic and aqueous extracts (25-100 mg/ml) exhibited significant anthelmintic activity at the used concentrations involving determination of paralysis and death time of the tested worms. Also the aqueous and ethanolic extracts (1 mg/disc each) exerted potent antifungal activity as a radial growth inhibition percentage against the tested plant pathogensB. cinerea(64.2 and 67.5 %) andF. oxysporum(65.3 and 73.6 %), whereas the MIC values of the tested extracts were found in the range of 1 to 3 mg/ml. [ABSTRACT FROM AUTHOR]

Stevia rebaudiana, a perennial herb from the Asteraceae family, is known to the scientific world for its sweetness and steviol glycosides (SGs). SGs are the secondary metabolites responsible for the sweetness of Stevia. They are synthesized by SG biosynthesis pathway operating in the leaves. Most of the genes encoding the enzymes of this pathway have been cloned and characterized from Stevia. Out of various SGs, stevioside and rebaudioside A are the major metabolites. SGs including stevioside have also been synthesized by enzymes and microbial agents. These are non-mutagenic, non-toxic, antimicrobial, and do not show any remarkable side-effects upon consumption. Stevioside has many medical applications and its role against diabetes is most important. SGs have made Stevia an important part of the medicinal world as well as the food and beverage industry. This article presents an overview on Stevia and the importance of SGs. [ABSTRACT FROM AUTHOR]

In the laboratory, using a PC12 cell system, studies have been conducted on the effects of various chemicals on apoptosis, as it is considered to be an essential part of normal development, maintenance, and defense in organisms. Stevioside is a natural sweetener extracted from the leaves of Stevia rebaudiana. Since it is widely used as a sugar replacement, it was decided to evaluate the toxicological effects of low concentrations of stevioside on apoptosis induced by serum deprivation using the PC12 cell system. It was found that based on data from DNA electrophoresis and TUNEL signal assays stevioside enhanced apoptosis induced by serum deprivation. This enhancement was caused by increased expression of Bax and of cytochrome c released into the cytosol. These findings suggest that stevioside affects the regulation of the normal apoptotic condition. Further investigation will be needed to clarify the detailed mechanism of the enhancement due to the treatment with stevioside. [ABSTRACT FROM AUTHOR]