(4R)-13-[(2-O-β-D-グルコピラノシル-3-O-β-D-グルコピラノシル-β-D-グルコピラノシル)オキシ]カウラ-16-エン-18-酸β-D-グルコピラノシル

The aim of this study was to elucidate the anti-inflammatory and immunomodulatory activities of stevioside and its metabolite, steviol. Stevioside at 1 mM significantly suppressed lipopolysaccharide (LPS)-induced release of TNF-alpha and IL-1beta and slightly suppressed nitric oxide release in THP-1 cells without exerting any direct toxic effect, whereas steviol at 100 uM did not. Activation of IKKbeta and transcription factor NF-kappaB were suppressed by stevioside, as demonstrated by Western blotting. Furthermore, only stevioside induced TNF-alpha, IL-1beta, and nitric oxide release in unstimulated THP-1 cells. Release of TNF-alpha could be partially neutralized by anti-TLR4 antibody. This study suggested that stevioside attenuates synthesis of inflammatory mediators in LPS-stimulated THP-1 cells by interfering with the IKKbeta and NF-kappaB signaling pathway, and stevioside-induced TNF-alpha secretion is partially mediated through TLR4.

In a study to investigate chemoprevention, the effect of rebaudioside A (purity >99.5%) on azoxymethane-induced aberrant crypt foci was studied in groups of male F344 rats. One group of 16 rats was given three weekly subcutaneous injections of azoxymethane for 2 weeks and a diet containing 200 mg rebaudioside A/kg for 5 weeks, from 1 week before to 2 weeks after azoxymethane administration, and was then sacrificed. The dose expressed as steviol was 6.6 ug/kg bw per day. Other groups received a diet containing rebaudioside A with no azoxymethane injections (6 rats), a basal diet with no azoxymethane (6 rats) or azoxymethane injections and a basal diet only (16 rats). At the end of the study, the colons were removed from eight animals in the test group and from one in each of the control groups and examined for aberrant crypt foci. The colonic mucosa of the remaining animals from each group were pooled and examined for ornithine decarboxylase activity. Silver-stained nucleolar organizer region (AgNOR) protein count was also determined for each group. Both ornithine decarboxylase and AgNOR number are biomarkers for cell proliferation. The average body weights and mean liver weights of the animals receiving the test compound and the azoxymethane injections were significantly lower than those of the animals receiving azoxymethane alone. No signs of toxicity were observed, and food consumption was unaffected by treatment. There was a non-significant trend for rebaudioside A to reduce the number of azoxymethane-induced aberrant crypt foci, mucosal ornithine decarboxylase activity and the number of AgNORs. /Rebaudioside A/

Stevioside inhibits the action of atractyloside on energy metabolism in the isolated perfused rat liver. The effects of atractyloside on glycolysis, glycogenolysis, gluconeogenesis and oxygen uptake are decreased by stevioside. The concentration for half-maximal action is 0.5 mM. The site of the action is located on the outside of the cell. Possibly, stevioside affects the transport of atractyloside across the cell membrane. /Stevioside/

In 2004, JECFA (Joint Expert Committee of Food Additives) issued a preliminary ADI (Allowed Daily Intake) of 2-mg/kg body weight (based on steviol) for stevia extract. This action may impact favorably on worldwide regulatory approval. As consumer's demand on naturally sweetened products increases, interest in Stevia, and naturally occurring potent sweeteners in general, is expected to grow.

Genus species Family: Stevia rebaudiana (Bertoni) Bertoni - Asteraceae. Common names: Stevia; Sweet Leaf of Paraguay(1).

Stevioside ... is a naturally occurring sweetener (approximately 200X) extracted from a South American plant, Stevia rebaudiana Bertoni. The dried leaves, the water extract of leaves, and the refined chemical ingredients, eg, and Rebaudioside A ... are collectively referred to as stevia. Discovered in Paraguay and Brazil, the plant was identified in the early 1970s as a plant of high economical value and transported to Japan for cultivation ... Today Stevia plant is cultivated primarily in China.

/HUMAN EXPOSURE STUDIES/ ... Beneficial effects of high doses of steviol glycosides on hyperglycemia and hypertension have been previously described when these abnormalities are present. This study was designed to evaluate the effects of steviol glycosides on blood glucose and on blood pressure (BP) in 3 groups of individuals. This was a randomized, double-blind, placebo-controlled, long-term study in three groups of patients: Group 1: subjects with Type 1 diabetes; Group 2: subjects with Type 2 diabetes; and Group 3: subjects without diabetes and with normal/low-normal BP levels. The subjects in each group were randomly allocated to active treatment (the steviol glycoside stevioside: 250 mg three times a day) or to placebo treatment and followed-up for 3 months. Post-treatment systolic BP, diastolic BP, glucose and glycated hemoglobin (HbA1c) were not significantly different from baseline measurements, except for the placebo Type 1 diabetics group where a significant difference was observed for systolic BP and glucose. No side effects were observed in the two treatment groups. This study shows that oral steviol glycosides, taken as sweetener are well tolerated and have no pharmacological effect. /Steviol glycosides/

/HUMAN EXPOSURE STUDIES/ ... This randomized, double-blind trial evaluated the hemodynamic effects of 4 weeks consumption of 1000 mg/day rebaudioside A vs. placebo in 100 individuals with normal and low-normal systolic blood pressure (SBP) and diastolic blood pressure (DBP). Subjects were predominantly female (76%, rebaudioside A and 82%, placebo) with a mean age of approximately 41 (range 18-73) years. At baseline, mean resting, seated SBP/DBP was 110.0/70.3mmHg and 110.7/71.2 mm Hg for the rebaudioside A and placebo groups, respectively. Compared with placebo, rebaudioside A did not significantly alter resting, seated SBP, DBP, mean arterial pressure (MAP), heart rate (HR) or 24-hr ambulatory blood pressures responses. These results indicate that consumption of as much as 1000 mg/day of rebaudioside A produced no clinically important changes in blood pressure in healthy adults with normal and low-normal blood pressure. /Rebaudioside A/

/HUMAN EXPOSURE STUDIES/ Four male and five female healthy volunteers (aged 21-29 years) were provided with capsules containing 250 mg stevioside (97% purity) to be taken 3 times per day for 3 days. Doses, expressed as steviol, were 288 mg/day or 4.4 mg/kg bw per day for females and 3.9 mg/kg bw per day for males. Twenty-four hour urine samples were taken before dosing on day 1 and after dosing on day 3. Fasting blood samples were taken before dosing on day 1, and six samples were taken at different time points on day 3 after dosing. Fasting blood pressure measurements were taken before the first capsule and at six different time intervals after the first dose. Urine was analysed for creatinine, sodium, potassium, calcium and urea. Blood was analyzed for plasma glucose, plasma insulin, alkaline phosphatase, ALT, GPT, creatine kinase and lactate dehydrogenase. The clinical analyses of blood, blood pressure and urine showed no differences between samples taken before or after dosing. /Stevioside/

/LABORATORY ANIMALS: Acute Exposure/ To evaluate the effect of crude extract of Stevia rebaudiana on renal water, Na+ and K+ excretion, male Wistar rats (250-350 g each) under antidiuresis or water diuresis conditions, were evaluated. During intravenous infusion of the extract (0.05 mg/min/100 g) no significant differences were detected in mean arterial pressure or renal hemodynamics parameters. In contrast, fractional water and sodium excretion and solute clearance increased significantly, in both groups of animals. In antidiuresis rats the extract significantly increased reabsorption of water by the collecting duct and in water diuresis animals the extract significantly increased free water clearance. The data suggest preferential action of the extract in the proximal tubular cells involved with salt transport mechanism.

/LABORATORY ANIMALS: Acute Exposure/ The present experiment was undertaken to evaluate the renal excretion of steviol, the aglycone of several natural products extracted from the leaves of Stevia rebaudiana, and to clarify the actual participation of this compound on the renal excretion of glucose in rats, which has been previously suggested as the preferential action of steviol on the Na+-glucose renal tubular transport system. Steviol was obtained by enzymatic hydrolysis of stevioside with pectinase. Thirty normal male Wistar rats weighing 345 g were used. After a control period, steviol was infused iv at three doses (0.5, 1.0 and 3.0 mg/kg/hr), according to classical clearance techniques. During all the experiments no significant changes in inulin clearance (Cin) and p-aminohipuric acid clearance (C PAH) were observed. Administration of steviol resulted in a statistically significant increase in the fractional sodium excretion (FeNa+), fractional potassium excretion (FeK+), urinary flow as percent of glomerular filtration rate (V/GFR) and glucose clearance (C G) when compared to controls, but these effects were absent with the dose of 0.5 mg/kg/hr. The steviol clearance (C S) was higher than the Cin and lower than the C PAH at all the doses employed in this study. The data suggest that steviol is secreted by renal tubular epithelium, causing diuresis, natriuresis, kaliuresis and a fall in renal tubular reabsorption of glucose. /Steviol/

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ ... The present study ... evaluated the safety of this sweetener when administered as a dietary admix at target exposure levels of 500, 1000, and 2000 mg/kg/day to Sprague-Dawley rats for 90 days. There were no treatment-related effects on the general condition and behavior of the animals as determined by clinical observations, functional observational battery, and locomotor activity assessments. Evaluation of clinical pathology parameters revealed no toxicologically relevant, treatment-related effects on hematology, serum chemistry, or urinalysis. Macroscopic and microscopic findings revealed no treatment-related effects on any organ evaluated. Lower mean body weight gains were noted in males in the 2000 mg/kg/day group throughout the study, which was considered to be test article related; however, given the small magnitude of the difference as compared to controls, this effect was not considered to be adverse. Results of this study ... demonstrate that dietary administration of high concentrations of rebaudioside A for 90 consecutive days to Sprague-Dawley rats was not associated with any signs of toxicity. /Rebaudioside A/

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/

/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

MEDICATION

Naturally occurring potent sweetener

Because no food additive petition has been presented to the FDA, stevioside and related materials cannot be used in the United States as food ingredients. An import alert against stevia was issued by the FDA in 1991. In 1995, however, the FDA revised this import alert to allow the importation and use of stevia as a dietary supplement, but not as a sweetener or an ingredient for foods.

Stevioside can be isolated from the leaves of Stevia by extraction with water or water - ethanol mixtures. Crude Stevia extracts are more or less purified, e.g., by treatment with calcium or magnesium hydroxides or carbonates. Further purification by ion-exchangers, or absorption of undesired ingredients is possible. Stevioside can be obtained from the extracts by precipitation with methanol. ... Rebaudioside A is isolated from Stevia leaves in a similar way to stevioside. The ratio of rebaudioside A to stevioside can be increased by extraction with methanol, and further purification with column chromatography yields rebaudioside-A-rich products. Stevioside can, in addition, be transformed enzymatically to rebaudioside A. Commercial production routes often fail to yield pure stevioside or rebaudioside A.

The dried leaves, the water extract of leaves, and the refined chemical ingredients, eg, Stevioside and Rebaudioside A ... (approximately 300X) /of Stevia rebaudiana Bertoni/ can all be used as sweetening agents. These are collectively referred to as stevia.

Discovered in Paraguay and Brazil, /Stevia rebaudiana Bertoni/ was identified in the early 1970s as a plant of high economical value and transported to Japan for cultivation, where the commercialization of stevia leaves extract as a natural sweetener became a success. Today Stevia plant is cultivated primarily in China. ... In Japan, enzymatically glycosylated blend of stevioside and rebaudioside A, which appears to impart a cleaner taste profile, is also available commercially.

Besides steviol, the leaves of Stevia rebaudiana contain a number of other sweet glycosides, the most important of which is rebaudioside A. Rebaudioside A is 13-O-beta-glycopyranosylsteviol-19-O-beta-glucopyranosyl-(1,3)-sophorosyl ester [58543-16-1], C44H70O23, mw 967.0. Further sweet constituents of Stevia leaves are other steviol glycosides, such as rebaudiosides, dulcoside, and steviolbioside.