Anti-Inflammatory and Immunomodulatory Activities of Stevioside and Its Metabolite Steviol on THP-1 Cells

Food sweeteners: Angels or clowns for human health?

With the global prevalence of obesity and diabetes continuing to rise, metabolic diseases caused by excessive sugar intake have become a significant public health issue. In this context, various sweeteners as sugar substitutes have been widely used in the food industry. Sweeteners are highly favored for their good safety profile, cost-effectiveness, low-calorie properties, and potential blood sugar regulation effects, and their applications have extended to fields such as pharmaceuticals and daily chemicals. However, recent studies indicate that the impact mechanisms of sweeteners on human health are more complex than previously understood, and the long-term safety of their use has sparked widespread concern in both academia and the public. This review systematically examines relevant literature from the past three decades, employing evidence-based medicine methods for screening and meta-analysis, aiming to comprehensively assess the potential effects of sweeteners on human metabolic indicators (including blood glucose homeostasis and body fat composition) and cancer risk. The discussion will unfold in the following four sections: (1) Definition and classification of sweeteners; (2) Application areas of various sweeteners; (3) Beneficial effects of sweetener use on human health; (4) Adverse effects of sweetener use on health issues in different population groups. Current evidence suggests that the rational use of specific types of sweeteners within recommended dosage ranges can effectively improve blood glucose control, promote weight management, and play a positive role in maintaining oral health. However, excessive or long-term use of certain sweeteners may disrupt gut microbiota balance, affect glucose and lipid metabolism homeostasis, increase cardiovascular disease risk, and potentially be associated with the occurrence of certain malignant tumors. Notably, sweetener exposure during pregnancy may affect the fetus through mechanisms such as epigenetic modifications, necessitating special caution in sweetener selection for pregnant women. This review aims to provide clinicians, nutritionists, and food science professionals with the latest evidence-based medical evidence, guiding consumers to make informed sweetener choices by weighing health benefits against potential risks. It also offers scientific basis for formula optimization and product development in the food industry, thereby promoting public health.

Effects of Mixing Ratio and Lactic Acid Bacteria Preparation on the Quality of Whole-Plant Quinoa and Whole-Plant Corn or Stevia Powder Mixed Silage

Quinoa is the only single plant that can meet all the nutritional needs of human, and its potential for feed utilization has been continuously explored, becoming a prosperous industry for poverty alleviation. In order to further tap the feeding value of whole quinoa, develop quinoa as a feed substitute for conventional crops such as corn, and improve its comprehensive utilization rate, this experiment analyzed the silage quality and mycotoxin content of mixed silage of whole-plant quinoa (WPQ) with whole-plant corn (WPC) or stevia powder(SP) in different proportions, and further improved the silage quality of mixed silage by using two lactic acid bacteria preparations (Sila-Max and Sila-Mix). The quality, microbial population, and mycotoxin levels of quinoa and corn silage, as well as that of the mixed silage of quinoa and stevia, were evaluated using single-factor analysis of variance. The impact of various lactic acid bacteria preparations on the quality of whole-quinoa and whole-corn mixed silage was investigated through two-factor analysis of variance. WPQ and WPC were mixed at the ratio of 5:5 (QB5), 6:4 (QB6), 7:3 (QB7), 8:2 (QB8), 9:1 (QB9) and 10:0 (QB10). SP was mixed with WPQ at the supplemental levels of 0.2% (QB10S2), 0.4% (QB10S4), 0.6% (QB10S6), 0.8% (QB10S8) and 1.0% (QB10S10). After 60 days of silage, the silage indexes, the number of harmful microorganisms, and the mycotoxin levels were measured, to explore the appropriate ratio of mixed silage. The membership function analysis showed that the quality of mixed silage of WPQ with SP was better, and the optimal addition amount of SP was 0.6%. The results of Max and Mix on the quality improvement test of WPQ with WPC mixed silage showed that the two lactic acid bacteria formulations increased CP and AA content, and reduced NH3-N/TN; pH was significantly lower than the control group (p < 0.01), and LA was significantly higher than the control group (p < 0.01). The microbial count results showed that the addition of lactic acid bacteria preparation significantly reduced the number of molds and aerobic bacteria, and the effect of Mix was better than that of Max. When the mixing ratio was between QB7 and QB10, mold was not detected in the lactic-acid-bacteria preparation groups. Max and Mix significantly reduced the levels of mycotoxins, both of which were far below the range of feed safety testing, and 16S rRNA sequencing revealed that the silage microbiota varied with different mixing ratios and whether lactic acid bacteria preparations were used. Max and Mix increased the relative abundance of Firmicutes, with Mix having a more significant effect, especially in the QB6 (65.05%) and QB7 (63.61%) groups. The relative abundance of Lactobacillus was significantly higher than that of the control group (p < 0.05). The relative abundance of Enterobacteriaceae and Streptococcus were negatively and positively correlated with the addition level of quinoa, respectively. Comprehensive analysis showed that adding 0.6% SP to the WPQ and using Mix in mixed silage of WPQ and WPC with the proportion of WPQ no less than 70% had the best silage effect, and was more beneficial to animal health.

Phytocompounds hesperidin, rebaudioside a and rutin as drug leads for the treatment of tuberculosis targeting mycobacterial phosphoribosyl pyrophosphate synthetase

The main aim of this study is to address the global health crisis posed by tuberculosis (TB) through the exploration of novel therapeutic strategies targeting Mycobacterial phosphoribosyl pyrophosphate synthetase (MtPrsA), an untried enzyme involved in essential metabolic pathways of Mycobacterium tuberculosis. This enzyme plays a crucial role in cell wall synthesis, nucleotide biosynthesis and amino acid synthesis in M tb. Any hindrance to these may affect the growth and survival of the organism. Phytochemicals were systematically screened for potential inhibitors to MtPrsA. Subsequently, based on molecular docking studies, three compounds, namely, hesperidin, rebaudiosideA and rutin were selected. The binding stabilities of these compounds were analyzed using molecular dynamics simulation. Based on the RMSD score obtained, the binding stability of the compounds was confirmed. To validate the findings, an enzyme inhibition assay was done using recombinant MtPrsA. Ligation Independent Cloning (LIC cloning) method was used to produce recombinant His-tagged MtPrsA, followed by purification using Histrap columns. Enzyme kinetic studies unveiled the distinct modes of inhibition exhibited by each compound towards MtPrsA. RebaudiosideA and rutin emerged as competitive inhibitors, while hesperidin showcased a mixed inhibition profile. In conclusion, the study contributes valuable insights into potential therapeutic strategies for TB, through the exploration of alternative enzyme targets and the identification of phytochemical inhibitors. Notably, todate, no effective plant compounds have been reported as inhibitors to MtPrsA.

Exploring the therapeutic targets of stevioside in management of type 2 diabetes by network pharmacology and in-silico approach

AIMS

The main objective of the current study is to investigate the pathways and therapeutic targets linked to stevioside in the management of T2D using computational approaches.

METHODS

We collected RNA-seq datasets from NCBI, then employed GREIN to retrieve differentially expressed genes (DEGs). Computer-assisted techniques DAVID, STRING and NetworkAnalyst were used to explore common significant pathways and therapeutic targets associated with T2D and stevioside. Molecular docking and dynamics simulations were conducted to validate the interaction between stevioside and therapeutic targets.

RESULTS

Gene ontology and KEGG analysis revealed that prostaglandin synthesis, IL-17 signaling, inflammatory response, and interleukin signaling were potential pathways targeted by stevioside in T2D. Protein-protein interactions (PPI) analysis identified six common hub proteins (PPARG, PTGS2, CXCL8, CCL2, PTPRC, and EDN1). Molecular docking results showed best binding of stevioside to PPARG (-8 kcal/mol) and PTGS2 (-10.1 kcal/mol). Finally, 100 ns molecular dynamics demonstrated that the binding stability between stevioside and target protein (PPARG and PTGS2) falls within the acceptable range.

CONCLUSIONS

This study reveals that stevioside exhibits significant potential in controlling T2D by targeting key pathways and stably binding to PPARG and PTGS2. Further research is necessary to confirm and expand upon these significant computational results.

Immunomodulating Phytochemicals: An Insight Into Their Potential Use in Cytokine Storm Situations

Phytochemicals are compounds found in plants that possess a variety of bioactive properties, including antioxidant and immunomodulatory properties. Recent studies have highlighted the potential of phytochemicals in targeting specific signalling pathways involved in cytokine storm, a life-threatening clinical condition resulting from excessive immune cell activation and oversupply of proinflammatory cytokines. Several studies have documented the immunomodulatory effects of phytochemicals on immune function, including their ability to regulate essential cellular and molecular interactions of immune system cells. This makes them a promising alternative for cytokine storm management, especially when combined with existing chemotherapies. Furthermore, phytochemicals have been found to target multiple signalling pathways, including the TNF-α/NF-κB, IL-1/NF-κB, IFN-γ/JAK/STAT, and IL-6/JAK-STAT. These pathways play critical roles in the development and progression of cytokine storm, and targeting them with phytochemicals represents a promising strategy for controlling cytokine release and the subsequent inflammation. Studies have also investigated certain families of plant-related constituents and their potential immunomodulatory actions. In vivo and in vitro studies have reported the immunomodulatory effects of phytochemicals, which provide viable alternatives in the management of cytokine storm syndrome. The collective data from previous studies suggest that phytochemicals represent a potentially functional source of cytokine storm treatment and promote further exploration of these compounds as immunomodulatory agents for suppressing specific signalling cascade responses. Overall, the previous research findings support the use of phytochemicals as a complementary approach in managing cytokine storm and improving patient outcomes.

Rebaudioside B Attenuates Lung Ischemia-reperfusion Injury Associated Apoptosis and Inflammation

OBJECTIVE

At present, no proven effective treatment is available for Lung Ischemiareperfusion Injury (LIRI). Natural compounds offer promising prospects for developing new drugs to address various diseases. This study sought to explore the potential of Rebaudioside B (Reb B) as a treatment compound for LIRI, both in vivo and in vitro.

METHODS

This study involved utilizing the human pulmonary alveolar cell line A549, consisting of epithelial type II cells, subjected to Oxygen-glucose Deprivation/recovery (OGD/R) for highthroughput in vitro cell viability screening. The aim was to identify the most promising candidate compounds. Additionally, an in vivo rat model of lung ischemia-reperfusion was employed to evaluate the potential protective effects of Reb B.

RESULTS

Through high-throughput screening, Reb B emerged as the most promising natural compound among those tested. In the A549 OGD/R models, Reb B exhibited a capacity to enhance cell viability by mitigating apoptosis. In the in vivo LIRI model, pre-treatment with Reb B notably decreased apoptotic cells, perivascular edema, and neutrophil infiltration within lung tissues. Furthermore, Reb B demonstrated its ability to attenuate lung inflammation associated with LIRI primarily by elevating IL-10 levels while reducing levels of IL-6, IL-8, and TNF-α.

CONCLUSION

The comprehensive outcomes strongly suggest Reb B's potential as a protective agent against LIRI. This effect is attributed to its inhibition of the mitochondrial apoptotic pathway and its ability to mitigate the inflammatory response.

Steviol Glycosides from Stevia rebaudiana: An Updated Overview of Their Sweetening Activity, Pharmacological Properties, and Safety Aspects

This literature-based review synthesizes the available scientific information about steviol glycosides as natural sweeteners and molecules with therapeutic potential. In addition, it discusses the safety concerns regarding human consumption. Steviol glycosides exhibit a superior sweetener proficiency to that of sucrose and are noncaloric, noncariogenic, and nonfermentative. Scientific evidence encourages stevioside and rebaudioside A as sweetener alternatives to sucrose and supports their use based on their absences of harmful effects on human health. Moreover, these active compounds isolated from Stevia rebaudiana possess interesting medicinal activities, including antidiabetic, antihypertensive, anti-inflammatory, antioxidant, anticancer, and antidiarrheal activity. The described bioactivities of steviol glycosides deserve special attention based on their dose dependence and specific pathological situations. Further clinical research is needed to understand underlying mechanisms of action, therapeutic indexes, and pharmacological applications.

Steviol glycosides affect functional properties and macromolecular expression of breast cancer cells

Steviol glycosides, the active sweet components of stevia plant, have been recently found to possess a number of therapeutic properties, including some recorded anticancer ones against various cancer cell types (breast, ovarian, cervical, pancreatic, and colon cancer). Our aim was to investigate this anticancer potential on the two most commonly used breast cancer cell lines which differ in the phenotype and estrogen receptor (ER) status: the low metastatic, ERα+ MCF-7 and the highly metastatic, ERα-/ERβ+ MDA-MB-231. Specifically, glycosides' effect was studied on cancer cells': (a) viability, (b) functionality (proliferation, migration, and adhesion), and (c) gene expression (mRNA level) of crucial molecules implicated in cancer's pathophysiology. Results showed that steviol glycosides induced cell death in both cell lines, in the first 24 hr, which was in line with the antiapoptotic BCL2 decrease. However, cells that managed to survive showcased diametrically opposite behavior. The low metastatic ERα+ MCF-7 cells acquired an aggressive phenotype, depicted by the upregulation of all receptors and co-receptors (ESR, PGR, AR, GPER1, EGFR, IGF1R, CD44, SDC2, and SDC4), as well as VIM and MMP14. On the contrary, the highly metastatic ERα-/ERβ+ MDA-MB-231 cells became less aggressive as pointed out by the respective downregulation of EGFR, IGF1R, CD44, and SDC2. Changes observed in gene expression were compatible with altered cell functions. Glycosides increased MCF-7 cells migration and adhesion, but reduced MDA-MB-231 cells migratory and metastatic potential. In conclusion, the above data clearly demonstrate that steviol glycosides have different effects on breast cancer cells according to their ER status, suggesting that steviol glycosides might be examined for their potential anticancer activity against breast cancer, especially triple negative breast cancer (TNBC).

Stevioside Enhances the Anti-Adipogenic Effect and β-Oxidation by Activating AMPK in 3T3-L1 Cells and Epididymal Adipose Tissues of db/db Mice

Stevioside, the primary sweetener in stevia, is a glycoside with numerous beneficial biological activities. However, its anti-adipogenic effects on tissue differentiation and adipose tissues remain to be thoroughly investigated. In this study, the anti-adipogenic effects of stevioside during the differentiation of 3T3-L1 cells and epididymal adipose tissues of db/db mice were investigated by measuring the lipid droplets stained with Oil Red O and an immunoblot assay. Immunoblot analysis revealed that stevioside downregulated the expression of peroxisome proliferator-activated receptor-gamma (PPARγ), sterol regulatory element-binding protein-1c (SREBP-1c), CCAAT/enhancer-binding protein alpha (C/EBPα), and fatty acid synthase (FAS). Additionally, the protein expression of carnitine palmitoyltransferase 1 (CPT1), silent mating type information regulation 2 homolog 1 (SIRT1), and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) increased following treatment with stevioside. Furthermore, stevioside increased the phosphorylation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), both in vitro and in vivo. The activity of AMPK in stevioside-treated 3T3-L1 cells was further confirmed using agonists and antagonists of AMPK signaling. Our data indicate that stevioside ameliorates anti-adipogenic effects and promotes β-oxidation in adipocytes by activating AMPK-mediated signaling. The results of this study clearly demonstrated the inhibitory effect of stevioside on the differentiation of adipocytes and the reduction of lipid accumulation in the epididymal adipose tissues of db/db mice.

Artificial Sweeteners: History and New Concepts on Inflammation

Since the introduction of artificial sweeteners (AS) to the North American market in the 1950s, a growing number of epidemiological and animal studies have suggested that AS may induce changes in gut bacteria and gut wall immune reactivity, which could negatively affect individuals with or susceptible to chronic inflammatory conditions such as inflammatory bowel disease (IBD), a disorder that has been growing exponentially in westernized countries. This review summarizes the history of current FDA-approved AS and their chemical composition, metabolism, and bacterial utilization, and provides a scoping overview of the disease mechanisms associated with the induction or prevention of inflammation in IBD. We provide a general outlook on areas that have been both largely and scarcely studied, emerging concepts using silica, and describe the effects of AS on acute and chronic forms of intestinal inflammation.

The role of metabolites of steviol glycosides and their glucosylated derivatives against diabetes-related metabolic disorders

Diabetes mellitus (DM), characterized by abnormal carbohydrate, lipid, and protein metabolism, is a metabolic disorder caused by a shortage of insulin secretion or decreased sensitivity of target cells to insulin. In addition to changes in lifestyle, a low-calorie diet is recommended to reduce the development of DM. Steviol glycosides (SGs), as natural sweeteners, have gained attention as sucrose alternatives because of their advantages of high sweetness and being low calorie. Most SGs with multiple bioactivities are beneficial to regulate physiological functions. Though SGs have been widely applied in food industry, there is little data on their glucosylated derivatives that are glucosylated steviol glycosides (GSGs). In this review, we have discussed the metabolic fate of GSGs in contrast to SGs, and the molecular mechanisms of glycoside metabolites against diabetes-related metabolic disorders are also summarized. SGs are generally extracted from the Stevia leaf, while GSGs are mainly manufactured using enzymes that transfer glucose units from a starch source to SGs. Results from this study suggest that SGs and GSGs share same bioactive metabolites, steviol and steviol glucuronide (SVG), which exhibit anti-hyperglycemic effects by activating glucose-induced insulin secretion to enhance pancreatic β-cell function. In addition, steviol and SVG have been found to ameliorate the inflammatory response, lipid imbalance, myocardial fibrosis and renal functions to modulate diabetes-related metabolic disorders. Therefore, both SGs and GSGs may be used as potential sucrose alternatives and/or pharmacological alternatives for preventing and treating metabolic disorders.

Transformation of 15-ene steviol by Aspergillus niger, Cunninghamella bainieri, and Mortierella isabellina

Transformation of 15-ene steviol (ent-13-hydroxy-kaur-15-en-19-oic acid) by growth cultures of Aspergillus niger BCRC 32720, Cunninghamella bainieri ATCC 9244, and Mortierella isabellina ATCC 38063 was conducted to generate various derivatives for the development of bioactive compounds. Four previously undescribed compounds along with six known compounds were obtained. The newly identified isolates were characterized using 1D and 2D NMR, IR, and HRESIMS, and three compounds were further confirmed by X-ray crystallographic analyses. Subsequently, the effects of 15-ene steviol and its derivatives on lipopolysaccharide (LPS)-induced cytokine production by THP-1 cells were examined, with dexamethasone used as a positive control. Results indicated that most of the tested compounds showed lower inhibitory effects than those detected in the dexamethasone-treated group, except that 15-ene steviol showed better effects than dexamethasone on the reduction of LPS-induced monocyte chemoattractant protein (MCP)-1, -2, and -3 release. Three specialized products similarly showed better effects than dexamethasone on the inhibition of LPS-induced secretion of regulated on activation, normal T cell expressed and secreted (RANTES). Moreover, none of the tested compounds showed any cytotoxicity or triggered cell apoptosis, and none affected the protein integrity of toll-like receptor 4 (TLR4) or MyD88, suggesting that these compounds may exert the anti-inflammatory activity downstream of membrane-associated TLR4 and MyD88 molecules.

Stevioside Activates AMPK to Suppress Inflammation in Macrophages and Protects Mice from LPS-Induced Lethal Shock

Stevioside, a diterpenoid glycoside, is widely used as a natural sweetener; meanwhile, it has been proven to possess various pharmacological properties as well. However, until now there were no comprehensive evaluations focused on the anti-inflammatory activity of stevioside. Thus, the anti-inflammatory activities of stevioside, both in macrophages (RAW 264.7 cells, THP-1 cells, and mouse peritoneal macrophages) and in mice, were extensively investigated for the potential application of stevioside as a novel anti-inflammatory agent. The results showed that stevioside was capable of down-regulating lipopolysaccharide (LPS)-induced expression and production of pro-inflammatory cytokines and mediators in macrophages from different sources, such as IL-6, TNF-α, IL-1β, iNOS/NO, COX2, and HMGB1, whereas it up-regulated the anti-inflammatory cytokines IL-10 and TGF-β1. Further investigation showed that stevioside could activate the AMPK -mediated inhibition of IRF5 and NF-κB pathways. Similarly, in mice with LPS-induced lethal shock, stevioside inhibited release of pro-inflammatory factors, enhanced production of IL-10, and increased the survival rate of mice. More importantly, stevioside was also shown to activate AMPK in the periphery blood mononuclear cells of mice. Together, these results indicated that stevioside could significantly attenuate LPS-induced inflammatory responses both in vitro and in vivo through regulating several signaling pathways. These findings further strengthened the evidence that stevioside may be developed into a therapeutic agent against inflammatory diseases.

Total Synthesis and Structural Revision of Rebaudioside S, a Steviol Glycoside

The total synthesis of rebaudioside S, a minor steviol glycoside from the leaves of Stevia rebaudiana, was investigated via a modular strategy, culminating not only in the first and highly efficient synthesis of Reb-S and analogues thereof but also in the revision of the originally proposed structure. The modular strategy dictated the application of C2-branched disaccharide Yu donors to forge C-13 steviol glycosidic linkages, posing considerable challenges in stereoselectivity control. Through systematic investigations, the effect of the internal glycosidic linkage configuration on the glycosylation stereoselectivity of 1,2-linked disaccharide donors was disclosed, and the intensified solvent effect by the 4,6-O-benzylidene protecting group was also observed with glucosyl donors. Through the orchestrated application of these favorable effects, the stereoselectivity problems were exquisitely tackled.

Anti-inflammatory effect of stevioside abates Freund's complete adjuvant (FCA)-induced adjuvant arthritis in rats

Adjuvant arthritis is a chronic, autoimmune and inflammatory disorder of the joints. The occurrence of disorder causes a severe damage to the connective tissue eventually leading to progressive physical disability and eventual death. The recent years of evidence suggests the anti-inflammatory properties of stevioside, a diterpene glycoside. However, the effect of stevioside against adjuvant arthritis, a chronic inflammatory disorder is not known. Hence, the present study was designed to study the effect of stevioside against Freund's complete adjuvant induced arthritis model in rats. The acute anti-inflammatory effect of stevioside also studied by employing carrageenan-induced paw oedema model in rats. The biochemical markers, haematological parameters, lipid peroxidation, myeloperoxidase activity, lipoxygenase activity, the levels of PGE2 and pro-inflammatory (TNF-α, IL-6 & IL-1β) and anti-inflammatory cytokine (IL-10) were analysed. The protein expression of NF-κB (p65) COX-2 and iNOS in paw tissues were estimated by western blotting. Stevioside treatment significantly ameliorates the adjuvant induced arthritic scoring, histological alterations, paw volume, elevation of biochemical (AST, ALT, ALP and glucose levels) and haematological (haemoglobin, differential and platelet count) parameters and restored the endogenous anti-oxidant (SOD, CAT, GSH and GST) activities. Treatment with stevioside also significantly prevented the adjuvant induced elevation of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β), pro-inflammatory protein expressions (iNOS, COX-2, NF-κB (p65) and pIκB/IκB ratio), prevented the increase in myeloperoxidase activity and significantly restored the anti-inflammatory (IL-10) cytokine level in paw tissues. Collectively, our findings suggest that stevioside may serve as anti-inflammatory agent and could serve as a potential adjunct therapeutic option in treating adjuvant arthritis.

Terpenoids as Potential Geroprotectors

Terpenes and terpenoids are the largest groups of plant secondary metabolites. However, unlike polyphenols, they are rarely associated with geroprotective properties. Here we evaluated the conformity of the biological effects of terpenoids with the criteria of geroprotectors, including primary criteria (lifespan-extending effects in model organisms, improvement of aging biomarkers, low toxicity, minimal adverse effects, improvement of the quality of life) and secondary criteria (evolutionarily conserved mechanisms of action, reproducibility of the effects on different models, prevention of age-associated diseases, increasing of stress-resistance). The number of substances that demonstrate the greatest compliance with both primary and secondary criteria of geroprotectors were found among different classes of terpenoids. Thus, terpenoids are an underestimated source of potential geroprotectors that can effectively influence the mechanisms of aging and age-related diseases.

NMR-based metabolomics approach reveals effects of antioxidant nutrients in sepsis-induced changes in rat liver injury

Oxidative stress and the production of intracellular reactive oxygen species (ROS) have been implicated in the pathogenesis of sepsis. In excess, oxidative stress is not deemed an unbalanced biochemical reaction in the critically ill rats, but it is a key pathological factor in driving systemic inflammatory response that can result in multiple organ failure in sepsis. Thus, we aimed to explore whether antioxidant nutrients could reduce or delay the oxidative stress condition of sepsis rats, and then play a prospective role in the oxidative stress condition of critical disease. In this investigation, the ability of exogenous and endogenous antioxidant nutrients (ascorbate, taurine and glutathione) to prevent sepsis-induced changes in liver injury was examined using a rat model of sepsis induced by cecal ligation and puncture (CLP), and the underlying mechanisms were also investigated. The effects of three antioxidants on sepsis were assessed based on biochemical assays in combination with an NMR-based metabolomics approach and correlation network analysis. Our results suggested that ascorbate, taurine and glutathione had broadly similar protective effects on reducing oxidative stress. Compared with CLP rats, antioxidant-treated rats exhibited alleviated (P<.05) organ dysfunction and improved liver pathology. Moreover, taurine showed a better efficacy compared with ascorbate and glutathione, evidenced by significantly reversed metabolomics profiles toward normal state. Under conditions of sepsis, antioxidants suppressed inflammatory responses by restraining key signaling pathways, including the redox-sensitive transcription factor pathways of NF-κB and MAPK. Collectively, our findings suggested that antioxidant nutrients exerted beneficial effects on septic rats via protecting mitochondrial.

Fermented Wild Ginseng by Rhizopus oligosporus Improved l-Carnitine and Ginsenoside Contents

We conducted this study to investigate the beneficial effects of Rhizopus oligosporus fermentation of wild ginseng on ginsenosides, l-carnitine contents and its biological activity. The Rhizopus oligosporus fermentation of wild ginseng was carried out at 30 °C for between 1 and 14 days. Fourteen ginsenosides and l-carnitine were analyzed in the fermented wild ginseng by the ultra high pressure liquid chromatography–mass spectrometry (UPLC–MS) system. Our results showed that the total amount of ginsenosides in ginseng increased from 3274 to 5573 mg/kg after 14 days of fermentation. Among the 14 ginsenosides tested, the amounts of 13 ginsenosides (Rg1, Rb2, Rb3, Rc, Rd, Re, Rf, Rg2, Rg3, Rh1, compound K, F1 and F2) increased, whereas ginsenoside Rb1 decreased, during the fermentation. Furthermore, l-carnitine (630 mg/kg) was newly synthesized in fermented ginseng extract after 14 days. In addition, both total phenol contents and DPPH radical scavenging activities showed an increase in the fermented ginseng with respect to non-fermented ginseng. These results show that the fermentation process reduced the cytotoxicity of wild ginseng against RAW264.7 cells. Both wild and fermented wild ginseng showed anti-inflammatory activity via inhibition of nitric oxide synthesis in RAW264.7 murine macrophage cells.

Effects of dietary sweeteners supplementation on growth performance, serum biochemicals, and jejunal physiological functions of broiler chickens

The objective of this study was to investigate the effects of dietary 3 kinds of sweeteners supplementation on growth performance, serum biochemicals, and jejunal physiological functions of broiler chickens for 21 D. A total of one hundred ninety-two 1-day-old male Ross 308 broiler chicks were randomly divided into 4 treatments with 6 replicates for each treatment. The treatments were basal diet (CON), a basal diet supplemented with 250 mg/kg stevioside (STE), a basal diet supplemented with 100 mg/kg sucralose (SUC), and a basal diet supplemented with 600 mg/kg saccharin sodium (SAC). All birds were housed in 3-level battery cages. The results showed that dietary STE supplementation increased (P < 0.05) growth performance, serum total protein, serum albumin, and jejunal antioxidant capacity of broiler chickens. Both SUC and SAC supplementation decreased (P < 0.05) serum total protein and albumin. Dietary SAC supplementation impaired the intestinal integrity, permeability, and mucus layer of the jejunum in broiler chickens. In addition, SAC supplementation elevated (P < 0.05) the transcription expression level of jejunal bitter taste receptors and induced excessive jejunal apoptosis. Our data suggest that STE could be potentially applied as a growth-promoting and antioxidant feed additive in broiler chickens. Whereas, dietary supplementation with high level SAC has side-effects on the jejunal physiological functions of broiler chickens.

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.

Stevia as a Natural Sweetener: A Review

Stevia rebaudiana of the Asteraceae family is a perennial shrub. It is a sweetener herb also known as sweet weed, sweet leaf, sweet herbs and honey leaf, native to Argentina, Brazil and Paraguay. The leaves of stevia are sweeter than sucrose with zero calories. Steviol, a diterpenoid glycoside derivative identified from this plant, is sweeter than sucrose and is safe when used as a sweetening agent. Diabetic and obese people with hyperglycemia who are in a condition to follow a strict diet can use stevioside as an alternative sweetener. In addition to its hypoglycemic property, the plant also exhibits antibacterial, anti-inflammatory, hypotensive, antiseptic, diuretic, anti-fertility and cardiotonic properties. It has also been documented to show good effects on treating skin diseases such as dermatitis, acne, eczema etc. The leaves of stevia with enriched phytoconstituents could be an alternative natural sweetener for children, adults and old age persons who have a craze to drink beverages and eat sweetened food products in their habitual life.

The first total synthesis of rebaudioside R

The first total synthesis of rebaudioside R has been achieved via two different approaches.

Dietary Stevioside Supplementation Alleviates Lipopolysaccharide-Induced Intestinal Mucosal Damage through Anti-Inflammatory and Antioxidant Effects in Broiler Chickens

The study was conducted to investigate the effects of dietary stevioside (STE) supplementation on the lipopolysaccharide (LPS)-induced intestinal mucosal damage of broiler chickens. A total of 192 one-day-old male Ross 308 broiler chicks were randomly divided into four treatments: (1) basal diet (CON); (2) basal diet supplemented with 250 mg/kg stevioside (STE); (3) basal diet + LPS-challenge (LPS); (4) basal diet supplemented with 250 mg/kg stevioside + LPS-challenge (LPS + STE). LPS-challenged groups received an intraperitoneal injection of LPS at 17, 19 and 21 d, whereas the CON and STE groups received a saline injection. The results showed that dietary STE supplementation normalized LPS-induced changes in protein expression of p-NF-κB and p-IκBα, mRNA expression of inflammatory genes (TLR4, NF-κB, and IFN-γ), tight junction-related genes (CLDN2, OCLN, and ZO-1), and antioxidant genes (Nrf2 and HO-1). LPS-induced decreases in serum diamine oxidase (DAO) level, villus height-to-crypt depth ratio, apoptotic index, and protein expression of proliferating cell nuclear antigen (PCNA) were reversed with dietary STE supplementation. Additionally, STE supplementation ameliorated the redox damage by reducing malondialdehyde (MDA) content and increasing total antioxidant capacity (T-AOC) and antioxidant enzyme activity. In conclusion, dietary stevioside supplementation could alleviate LPS-induced intestinal mucosal damage through anti-inflammatory and antioxidant effects in broiler chickens.

Changes in nutrient and calorie intake, adipose mass, triglycerides and TNF-α concentrations after non-caloric sweetener intake: A pilot study

Establishing the safety of non-caloric sweetener consumption in humans is a difficult task, since many contradictory results have been reported. The objective of this study was to compare the effect of frequent intake of sucrose, sucralose or steviol glycosides, on selected anthropometric, biochemical and immunological parameters in healthy, young adults. 38 individuals with normal body mass index were recruited and randomly divided into three experimental groups. After a washout week (where food with added sweeteners was restricted), each group was supplemented with sucrose (8 × 5 g packets/day), sucralose or steviol glycosides (4 × 1 g packets/day each) for 6 weeks. Selected variables were measured before and after treatment in each group and differences within and among groups were assessed. Our results showed that, compared to baseline, there was a modest but significant increase in weight (p = 0.0293) in the sucralose group, while the steviol glycosides group reduced their fat mass (p = 0.0390). No differences were observed in glycaemia; however, there was a significant increase in serum triglycerides (77.8-110.8 mg/dL) and cholesterol (162.0-172.3 mg/dL) in the sucrose group, whereas the steviol glycosides group presented lower triglycerides (104.7-92.8 mg/dL) and TNF-α concentrations (51.1-47.5 pg/mL). Comparison among groups showed differences in serum triglycerides (p = 0.0226), TNF-α (p = 0.0460) and IL-β (p = 0.0008). Our results suggest that, even in a short time span, frequent intake of steviol glycosides may have positive effects on metabolic parameters that may be relevant for human health.

Review of the scientific evidence and technical opinion on noncaloric sweetener consumption in gastrointestinal diseases

The present review of noncaloric sweeteners (NCSs) by the Asociación Mexicana de Gastroenterología was carried out to analyze and answer some of the most frequent questions and concerns about NCS consumption in patients with gastrointestinal disorders, through a thorough review of the medical literature. A group of gastroenterologists and experts on nutrition, toxicology, microbiology, and endocrinology reviewed and analyzed the published literature on the topic. The working group formulated conclusions, based on the scientific evidence published, to give an opinion with respect to NCS ingestion. Current evidence does not confirm the carcinogenic potential of NCSs. However, the studies analyzed showed that saccharin could have a proinflammatory effect and that polyols can cause gastrointestinal symptoms and manifestations, depending on the dose and type of compound. The ingestion of xylitol, erythritol, sucralose, aspartame, acesulfame K, and saccharin could increase the secretion of the gastrointestinal hormones that regulate intestinal motility, and stevia and its derivatives could have a favorable effect on the percentage of liver fat. Caution should be taken in recommending aspartame consumption in patients with chronic liver disease because it reduces the ratio of branched-chain amino acids to aromatic amino acids. In addition, NCS ingestion could modify the composition of the intestinal microbiota, having an effect on gastrointestinal symptoms and manifestations. It is important to continue conducting causality studies on humans to be able to establish recommendations on NSC consumption.

Renoprotective effects of stevia (Stevia rebaudiana Bertoni), amlodipine, valsartan, and losartan in gentamycin-induced nephrotoxicity in the rat model: Biochemical, hematological and histological approaches

The current study investigated the renoprotective effects of stevia, angiotensin-II type 1 receptor (AT1) blocker and calcium (Ca2+) channel blocker in gentamycin-induced nephrotoxicity in rat models. Six groups of male Sprague-Dawley rats of eight weeks old were taken for the experiment: sham control, nephrotoxicity, treatment with amlodipine (4 mg/kg/day); stevia (200 mg/kg/day); losartan (15 mg/kg/day) and valsartan (5 mg/kg/day), accordingly. The blood sample was taken for the assessment of renal and hepatic-functional variables like serum creatinine, blood urea, BUN and SGPT, SGOT, and total serum bilirubin. Hematological parameters were also examined. Histological examination has been done on kidneys and liver. Alterations of the body weight and the organ's weight were documented. Treatment with stevia and valsartan significantly decreased serum creatinine levels. A reduction of liver enzymes, and total serum bilirubin levels were observed in all the treatment groups. Treatment with valsartan and amlodipine, remarkably and stevia, mildly reduced the renal tissue damage, inflammation, and tubular necrosis. However, the present study demonstrated that losartan treatment aggravated kidney damage by increasing protein cast, calcification, tubular necrosis, and injury. This comparison indicated that both stevia and valsartan have beneficial renoprotective effect and valsartan offers a better treatment option in renal damage over losartan.

Stevioside, a diterpenoid glycoside, shows anti-inflammatory property against Dextran Sulphate Sodium-induced ulcerative colitis in mice

Inflammatory bowel disease is an umbrella-term used to describe a set of chronic inflammatory conditions that affect the gastro-intestinal tract. Since most of the inflammatory medications in current use have several undesirable side-effects, stevioside, a naturally occurring, high-intensity sweetener was assessed in our study for its anti-inflammatory properties by in-vitro and in-vivo experiments. Stevioside was observed to significantly inhibit the levels of LPS induced elevation of cytokines, TNF-α (P < 0.05) and IL-6 (P < 0.001) as well as the production of reactive oxygen species (P < 0.01) and nitrites (P < 0.001) in RAW264.7 cells. Stevioside has also been evaluated for its anti-inflammatory effect by using dextran sulfate sodium (DSS)-induced ulcerative colitis model in mice. Stevioside significantly reduced the disease activity index (DAI) score, ameliorated the inflammatory symptoms induced by DSS in mice and exhibited intact colon histo-architecture. Stevioside treatment significantly inhibited the levels of pro-inflammatory cytokines, TNF-α and IL-6, and the protein expressions of pro-inflammatory mediators, COX-2 (P < 0.01) and iNOS (P < 0.01) and restored the levels of endogenous anti-oxidants such as superoxide dismutase (P < 0.01), catalase (P < 0.001), glutathione s-transferase (P < 0.001) and reduced glutathione (P < 0.001) level in colon tissues. It was also observed that stevioside significantly suppressed NF-κB (p65) activation by abrogating IκB phosphorylation and attenuated the phosphorylation of p38, ERK and JNK proteins in colon tissues. The findings of the present study suggest that stevioside exhibits anti-inflammatory property by inhibiting NF-κB (p65) and MAPK pathways and can be employed as an adjunct in nutraceuticals to treat IBD.

Rebaudioside A administration prevents experimental liver fibrosis: an in vivo and in vitro study of the mechanisms of action involved

Rebaudioside A (Reb A) is a diterpenoid isolated from the leaves of Stevia rebaudiana (Bertoni) that has been shown to possess pharmacological activity, including anti-inflammatory and antioxidant properties. However, the ability of Reb A to prevent liver injury has not been evaluated. Therefore, we aimed to study the potential of Reb A (20 mg/kg; two times daily intraperitoneally) to prevent liver injury induced by thioacetamide (TAA) administration (200 mg/kg; three times per week intraperitoneally). In addition, cocultures were incubated with either lipopolysaccharide or ethanol. Antifibrotic, antioxidant and immunological responses were evaluated. Chronic TAA administration produced considerable liver damage and distorted the liver parenchyma with the presence of prominent thick bands of collagen. In addition, TAA upregulated the expression of α-smooth muscle actin, transforming growth factor-β1, metalloproteinases 9, 2 and 13, and nuclear factor kappaB and downregulated nuclear erythroid factor 2. Reb A administration prevented all of these changes. In cocultured cells, Reb A prevented the upregulation of genes implicated in fibrotic and inflammatory processes when cells were exposed to ethanol and lipopolysaccharide. Altogether, our results suggest that Reb A prevents liver damage by blocking oxidative processes via upregulation of nuclear erythroid factor 2, exerts immunomodulatory effects by downregulating the nuclear factor-κB system and acts as an antifibrotic agent by maintaining collagen content.

Antioxidant and immunomodulatory activity induced by stevioside in liver damage: In vivo, in vitro and in silico assays

AIMS

Stevioside is a diterpenoid obtained from the leaves of Stevia rebaudiana (Bertoni) that exhibits antioxidant, antifibrotic, antiglycemic and anticancer properties. Therefore, we aimed to study whether stevioside has beneficial effects in liver injury induced by long-term thioacetamide (TAA) administration and investigated the possible underlying molecular mechanism using in vivo, in vitro and in silico approaches.

MAIN METHODS

Liver injury was induced in male Wistar rats by TAA administration (200 mg/kg), intraperitoneally, three times per week. Rats received saline or stevioside (20 mg/kg) twice daily intraperitoneally. In addition, cocultures were incubated with either lipopolysaccharide or ethanol. Liver injury, antioxidant and immunological responses were evaluated.

KEY FINDINGS

Chronic TAA administration induced significant liver damage. In addition, TAA upregulated the protein expression of nuclear factor (NF)-κB, thus increasing the expression of proinflammatory cytokines and decreasing the antioxidant capacity of the liver through downregulation of nuclear erythroid factor 2 (Nrf2). Notably, stevioside administration prevented all of these changes. In vitro, stevioside prevented the upregulation of several genes implicated in liver inflammation when cocultured cells were incubated with lipopolysaccharide or ethanol. In silico assays using tumor necrosis factor receptor (TNFR)-1 and Toll-like receptor (TLR)-4-MD2 demonstrated that stevioside docks with TNFR1 and TLR4-MD2, thus promoting an antagonistic action against this proinflammatory mediator.

SIGNIFICANCE

Collectively, these data suggest that stevioside prevented liver damage through antioxidant activity by upregulating Nrf2 and immunomodulatory activity by blocking NF-κB signaling.

Diversity-Oriented Synthesis of Steviol Glycosides

With cheap and easily available mixtures of steviol glycosides as starting materials, a practical method for steviol acquisition has been developed, on the basis of which a facile, diversity-oriented, and economic protocol for the synthesis of structurally defined steviol glycosides was established. The novel approach is featured by the highly efficient glycosylation of sterically hindered and acid-sensitive steviol via orchestrated application of Yu glycosylation, Schmidt glycosylation, and PTC glycosylation. Hence, these high-intensity sweeteners and potential lead compounds for drug development are now readily accessible.

Stevia rebaudiana Bertoni and Its Effects in Human Disease: Emphasizing Its Role in Inflammation, Atherosclerosis and Metabolic Syndrome

PURPOSE OF REVIEW

Stevia rebaudiana Bertoni is a perennial shrub with zero calorie content that has been increasing in popularity for its potential use as an adjuvant in the treatment of obesity. The level of evidence supporting general benefits to human health is insufficient. We conducted a review of the literature summarizing the current knowledge and role in human disease.

RECENT FINDINGS

Despite stevia's minimal systemic absorption, studies have been promising regarding its potential benefits against inflammation, carcinogenesis, atherosclerosis glucose control, and hypertension. On the other hand, the growing popularity of artificial sweeteners does not correlate with improved trends in obesity. An increased intake of artificial non-caloric sweeteners may not be associated with decreased intake of traditional sugar-sweetened beverages and foods. The effects of Stevia on weight change have been linked to bacteria in the intestinal microbiome, mainly by affecting Clostridium and Bacteroides sp.

POPULATIONS

A growing body of evidence indicates that Stevia rebaudiana Bertoni is protective against malignant conversion by inhibition of DNA replication in human cancer cell growth in vitro. Consumption of Stevia has demonstrated to be generally safe in most reports. Further clinical studies are warranted to determine if regular consumption brings sustained benefits for human health.

Reduction of the Oxidative Stress Status Using Steviol Glycosides in a Fish Model (Cyprinus carpio)

Steviol glycosides are sweetening compounds from the Stevia rebaudiana Bertoni plant. This product is considered safe for human consumption and was approved as a food additive by the Food and Drugs Administration (FDA) and European Food Safety Authority (EFSA). Its effects on the ecosystem have not been studied in depth; therefore, it is necessary to carry out ecotoxicological studies in organisms such as Cyprinus carpio. The present study aimed to evaluate the antioxidant activity by SGs on diverse tissues in C. carpio using oxidative stress (OS) biomarkers. To test the antioxidant activity, carps were exposed to four systems: (1) SGs free control, (2) CCl₄ 0.5 mL/kg, (3) SGs 1 g/L, and (4) CCl₄ 0.5 mL/kg + SGs 1 g/L at 96 h. The following biomarkers were analyzed: lipoperoxidation (LPX), hydroperoxide content (HPC), and protein carbonyl content (PCC), as well as antioxidant activity of superoxide dismutase (SOD) and catalase (CAT). It was found that both (3 and 4) systems' exposure decreases LPX, CHP, PCC, SOD, and CAT with respect to the CCl₄ system. The results of this study demonstrate that the concentrations of SGs used are not capable of generating oxidative stress and, on the contrary, would appear to induce an antioxidant effect.

Glycosides from Stevia rebaudiana Bertoni Possess Insulin-Mimetic and Antioxidant Activities in Rat Cardiac Fibroblasts

Stevia rebaudiana Bertoni is a shrub having a high content of sweet diterpenoid glycosides in its leaves, mainly stevioside and rebaudioside A, which are used as noncaloric, natural sweeteners. The aim of this study was to deepen the knowledge about the insulin-mimetic effect exerted by four different mixtures of steviol glycosides, rich in stevioside and rebaudioside A, in neonatal rat cardiac fibroblasts. The potential antioxidant activity of these steviol glycosides was also assessed, as oxidative stress is associated with diabetes. Likewise the insulin effect, steviol glycosides caused an increase in glucose uptake into rat fibroblasts by activating the PI3K/Akt pathway, thus inducing Glut4 translocation to the plasma membrane. The presence of S961, an insulin antagonist, completely abolished these effects, allowing to hypothesize that steviol glycosides could act as ligands of the same receptor engaged by insulin. Moreover, steviol glycosides counteracted oxidative stress by increasing reduced glutathione intracellular levels and upregulating expression and activity of the two antioxidant enzymes superoxide dismutase and catalase. The present work unravels the insulin-mimetic effect and the antioxidant property exerted by steviol glycosides, suggesting their potential beneficial role in the cotreatment of diabetes and in health maintenance.

Synthesis of C-4-Substituted Steviol Derivatives and Their Inhibitory Effects against Hepatitis B Virus

ent-13-Hydroxykaur-16-ene-19-N-butylureide (6) was one of 33 synthesized C-4-substituted steviol derivatives that were evaluated for their effects on hepatitis B virus (HBV) surface antigen (HBsAg) secretion. The IC₅₀ (16.9 μM) and SI (57.7) values for inhibiting HBV DNA replication of compound 6 were greater than those of the reference compound, lamivudine (3-TC; IC₅₀: 107.5 μM; SI: 22.0). Thus, the anti-HBV mechanism of 6 was investigated, and it specifically inhibited viral gene expression and reduced viral DNA levels, as well as potently attenuated all of the viral promoter activity of HBV-expressing Huh7 cells. Examination of cellular signaling pathways found that 6 inhibited the activities of the nuclear factor (NF)-κB- and activator protein (AP)-1 element-containing promoters, but had no effects on AP-2 or interferon-stimulated response element (ISRE)-containing promoters in HBV-expressing cells. Meanwhile, it significantly eliminated NF-κB and extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling-related protein levels and inhibited their phosphorylation in HBV-transfected Huh7 cells. The inhibitory potency of 6 against HBV DNA replication was reversed by cotransfecting the NF-κB p65 expression plasmid. Using the MAPK-specific activator anisomycin also reversed the inhibitory effect of 6 on viral DNA replication. The present findings suggest that the anti-HBV mechanism of 6 is partly mediated through the NF-κB and MAPK signaling pathways.

From Caá-ehé to a commercial sweetener - the diterpenoid glycosides of Stevia rebaudiana

The isolation, structure elucidation, chemistry, biosynthesis and biological activity of the sweet steviol glycosides from Stevia rebaudiana, are reviewed.

Is Stevia rebaudiana Bertoni a Non Cariogenic Sweetener? A Review

Stevia rebaudiana Bertoni is a small perennial shrub of the Asteraceae (Compositae) family that is native to South America, particularly Brazil and Paraguay, where it is known as "stevia" or "honey leaf" for its powerful sweetness. Several studies have suggested that in addition to their sweetness, steviosides and their related compounds, including rebaudioside A and isosteviol, may offer additional therapeutic benefits. These benefits include anti-hyperglycaemic, anti-hypertensive, anti-inflammatory, anti-tumor, anti-diarrheal, diuretic, and immunomodulatory actions. Additionally, critical analysis of the literature supports the anti-bacterial role of steviosides on oral bacteria flora. The aim of this review is to show the emerging results regarding the anti-cariogenic properties of S. rebaudiana Bertoni. Data shown in the present paper provide evidence that stevioside extracts from S. rebaudiana are not cariogenic. Future research should be focused on in vivo studies to evaluate the effects on dental caries of regular consumption of S. rebaudiana extract-based products.

Stevioside plays an anti-inflammatory role by regulating the NF-κB and MAPK pathways in S. aureus-infected mouse mammary glands

Mastitis is an inflammatory disease caused by microbial infection. Staphylococcus aureus is one of the primary bacteria responsible for mastitis. Stevioside is isolated from Stevia rebaudiana and is known to have therapeutic functions. This study was designed to evaluate the effects of stevioside in a mouse model of S. aureus-induced mastitis. In this study, the mouse mammary gland was infected with S. aureus to induce the mastitis model. The stevioside was administered intraperitoneally after the S. aureus infection was established. Hematoxylin-eosin (HE) staining, ELISA, Western blot, and q-PCR methods were used. The results show that stevioside significantly reduced the inflammatory cell infiltration and the levels of TNF-α, IL-1β, and IL-6 and the respective expression of their messenger RNAs (mRNAs). Further studies revealed that stevioside downregulated the TLR2, NF-κB, and (mitogen-activated protein kinase) MAPK signaling pathways in the S. aureus-infected mouse mammary gland. Our results demonstrate that stevioside reduced the expression of TNF-α, IL-1β, and IL-6 by inhibiting the phosphorylation of proteins in the NF-κB and MAPK signaling pathways dose-dependently, but that their mRNA expression was not obviously changed.