STEVIA: AN EMERGING NATURAL SWEETENER FOR FOOD INDUSTRY

About Authors:
Singh Asheesh^1*, Bajpai Dinesh¹, Singour P.K.^2
1Centre for Research & Development, Ipca Laboratories Ltd; Sejavta; Ratlam (MP) - 457002
²Faculty of pharmacy VNS Institute, Neelbud Bhopal (MP) - 462042
*asheesh_parihar@yahoo.com

Abstract:
Stevia rebaudiana is a well known medicinal herb contains antibacterial, antifungal, anti-inflammatory, anti-viral, anti-yeast, cardiotonic diuretic and hypoglycaemic properties. This herb has been used in Ayurveda in India since centuries. Stevia is a perennial herb belonging to the family Asteraceae, is one of the most valuable tropical medicinal plant. All over world there is increasing tendency towards consuming natural products and thus living a natural life and. At the same time our life styles have changed so much over the last 4-5 decades that sweeteners (either high calorie natural or proceeded sugars or high potency and low calorie sweeteners such as Aspartame) have become integral part of our natural daily diet. Stevia is a new crop in that is gaining very high popularity amongst all type of sweetener users as most ideal substitute for sugar. Sugar is basically a chemical that has grown in market over last many years. But in this age of changing life styles and people becoming more conscious of their health, the worldwide sugar consumption is going down and is getting replaced by low calorie sweeteners. Many of these Sweeteners are complex chemicals or many times naturals as well.

Reference Id: PHARMATUTOR-ART-1362

Introduction:
In the last couple of decades, growing concern about health and life quality has encouraged people to exercise, eat healthy food and decrease the consumption of food rich in sugar, salt and fat. Omission of added sucrose in foods increases the relative proportion of polymeric carbohydrates that may have beneficial effect for a balanced food intake as well as for human health¹. Stevia is a genusof about 240 speciesof herbsand shrubsin the sunflower family (Asteraceae), native to subtropicaland tropicalregions from western North Americato South America. The species Stevia rebaudiana, commonly known as sweet leaf, sweet leaf, sugar leaf, or simply stevia, is widely grown for its sweet leaves. As a sweetener and sugar substitute, stevia's taste has a slower onset and longer duration than that of sugar, although some of its extracts may have a bitter or licorice-like aftertaste at high concentrations with its steviol glycoside extracts having up to 300 times the sweetnessof sugar, stevia has garnered attention with the rise in demand for low-carbohydrate, low-sugar food alternatives. Because stevia has a negligible effect on blood glucose, it is attractive as a natural sweetener to people on carbohydrate-controlled diets. The availability of stevia varies from country to country. In a few countries, it has been available as a sweetener for decades or centuries; for example, stevia is widely used as a sweetener in Japanwhere it has been available for decades^2-3. In some countries health concerns and political controversieshave limited its availability; for example, the United States banned stevia in the early 1990s unless labeled as a dietary supplement, but in 2008 approved rebaudioside A extract as a food additive. Over the years, the number of countries in which stevia is available as a sweetener has been increasing. In 2011, stevia was approved for use in the EUstarting in early December, 2011^4-5.

Taxonomical Classification

History
In 1899, the Swiss botanist Moisés Santiago Bertoni, during his research in eastern Paraguay first described the plant and the sweet taste in detail. Only limited research was conducted on the topic until, in 1931, two French chemists isolated the glycosides that give stevia its sweet taste. These compounds were named stevioside and rebaudioside, and are 250–300 times as sweet as sucrose, heat stable, pH stable, and non-fermentable. The exact structure of the aglycone and the glycoside were published in 1955. In the early 1970s, Japan began cultivating stevia as an alternative to artificial sweeteners such as cyclamate and saccharin, which were suspected carcinogens. The plant's leaves, the aqueous extract of the leaves, and purified steviosides are used as sweeteners. Since the Japanese firm Morita Kagaku Kogyo Co., Ltd. produced the first commercial stevia sweetener in Japan in 1971, the Japanese have been using stevia in food products, soft drinks (including Coca Cola), and for table use. Japan currently consumes more stevia than any other country, with stevia accounting for 40% of the sweetener market^6-10.

Today, stevia is cultivated and used in food elsewhere in East Asia, including in China (since 1984), Korea, Taiwan, Thailand, and Malaysia. It can also be found in Saint Kitts and Nevis, in parts of South America (Brazil, Colombia, Peru, Paraguay, and Uruguay), and in Israel. China is the world's largest exporter of stevioside. The genus Stevia consists of 240 species of plants native to South America, Central America, and Mexico, with several species found as far north as Arizona, New Mexico, and Texas^11-12. They were first researched by Spanish botanist and physician Petrus Jacobus Stevus (Pedro Jaime Esteve), from whose surname originates the Latinized word stevia¹³. The leaves of the stevia plant have 30–45 times the sweetness of sucrose (ordinary table sugar). The leaves can be eaten fresh, or put in teas and foods. The plant was used extensively by the Guaraní people for more than 1,500 years and the plant has a long history of medicinal use in Paraguay and Brazil. The leaves have been traditionally used for hundreds of years in Paraguay and Brazil to sweeten local teas, medicines and as a "sweet treat"¹⁴.

NOW YOU CAN ALSO PUBLISH YOUR ARTICLE ONLINE.

SUBMIT YOUR ARTICLE/PROJECT AT articles@pharmatutor.org

Subscribe to PharmaTutor Alerts by Email

FIND OUT MORE ARTICLES AT OUR DATABASE

Phytoconstituents of Stevia
Steviol Glycosides
The Joint Expert Committee on Food Additives (JECFA) committee in its fifty-first meeting (1999) stated that “Before the substance is reviewed again specifications should be developed to ensure that the material tested is representative of the material of commerce. Further information was required on the nature of the substance that was tested, on the metabolism of the Stevioside in humans and on the activity of Steviol in suitable studies of Genotoxicity in- vivo.”

JECFA in its 63^rd meeting (2004) at Geneva has noted that “Steviol glycosides are natural constituents of the plant Stevia rebaudiana bertoni which contain at least ten different glycosides, the major constituents being Stevioside and Rebaudioside A”. The material evaluated at that meeting contains not less than 95% glycosylated derivatives of Steviol, primarily Stevioside, Rebaudioside A and C and Dulcoside A, with minor amounts of Rubausoside, Steviolbioside and Rebuioside B, D, E and F. In the same meeting the JECFA has brought out a detailed tentative specifications of the Steviol glycosides which includes
1. Stevioside
2. Rebaudioside A
3. Rebaudioside C
4. Dulcoside A

JECFA has allotted a temporary ADI of 0 to 2 mg/kg BW for Steviol glycoside (expressed as Steviol) on the basis of the NOEL for Stevioside (970 mg/kg bw/day or 383 mg/kg bw/day, expressed as Steviol in the two years) after a study on rats and using a safety factor of 200. This safety factor incorporates a factor of 100 for inter and intra species differences and an additional factor of 2 because of the need for further information.

The committee noted that this temporary ADI only applies to products complying with the specifications. New tentative specifications were prepared, accompanied by a chemical and technical assessment. JECFA also recommended for the collection of following information for commercially available products¹⁵.

·         Analytical data on distribution and concentration of all components Steviol glycosides, including those that were not identified in the tentative specifications.

·         Method of analysis for the determination of all components Steviol glycosides, including those that were not identified in the tentative specifications.

·         The nature and concentration of the fractions that do not contain Steviol glycosides.

·         The quantities of residual solvents from isolation & purification steps of the manufacturing process.

·         The hydrolytic stability of the Steviol glycoside in acidic foods and beverages.

Chemical Name:
The following are the chemical names for the principal and secondary Steviol glycosides:
Stevioside: 13-[(2-O-β-D-glucopyranosyl-β-D-glucopyranosyl) oxy] kaur-16-PM-18-oic acid β-Dglucopyranosyl ester.

Rebaudioside A: 13-[(2-O-β-D-glucopyranosyl-3-β-Dglucopyranosyl-β-D-glucopyranosyl] oxy.kaur-16-PM-18-oic acid β-Dglucopyranosyl ester.

Rebaudioside C: 13-[(2-O-α-L-rhamnopyranosyl-3-O--β-Dglucopyranosyl- β-D-glucopyranosyl -β- D-glucopyranosyl-β-D-glucopyranosyl] oxy. kaur-16-PM-18-oic acid β-D- glucopyranosyl ester.

Dulcoside A: 13-[2-O-α-L-rhamnopyranosyl-β-Dglucopyranosyl] oxy kaur-16-PM-18-oicacid β-D- glucopyranosyl ester.

Chemical formula: 
The following are the chemical formulas for the principal and secondary Steviol glycosides:
Stevioside: C38H60O18

Rebaudioside A: C44H70O23

Rebaudioside C: C44H70O22

Dulcoside A: C38H60O17

Chemical structures of Steviol Glycosides:

Steviol (R1=R2=H) is the aglycone of the Steviol glycosides. Glc and Rha represent, respectively, glucose and Rhamnose sugar moieties.

Pharmacological studies:
Antihyperglycemic Effect of Stevioside
Department of Endocrinology and Metabolism C, Denmark studied Antihyperglycemic effect of Stevioside in type 2 diabetic subjects. The acute effects of Stevioside in type 2 diabetic patients were studied. 12 type 2 diabetic patients were included in an acute, paired crossover study. A standard test meal was supplemented with either 1g of Stevioside or 1g of maize starch (control). Blood samples were drawn at 30 minutes before and for 240 minutes after ingestion of the test meal. The authors concluded that as compared to control, Stevioside reduce the incremental area under the glucose response curve by 18% (P= 0.013). The insulinogenic index (AUC (i insulin)/ AUC (i, glucose) was increased by ~ 40% by Stevioside compared to control (P<0.001) ¹⁶. Therefore “Stevioside reduces postprandial blood glucose levels in type 2 diabetic patients indicating beneficial effects on the glucose metabolism. Stevioside may be advantageous in the treatment of type 2 diabetes.

Antihypertensive effect of Stevioside
A double-blind placebo-controlled study of the effectiveness and tolerability of oral Stevioside in human hypertension was studied and no significant adverse effect was observed and quality of life assessment showed no deterioration.  Although the hypotensive effect of Stevioside was not better than other antihypertensive drugs, it appears comparable and almost all the active drugs. Almost all the active treatment group patients showed significant lowering of blood pressure. The antihypertensive effect of crude Stevioside obtained from the leaves of S.rebaudiana (Bertoni) Bertoni (Compositae) on previously untreated mild hypertensive patients was examined.

All adverse events were prospectively recorded but no major adverse clinical effects were observed ruing the trial. Systolic and diastolic blood pressure decreased (p<0.05) during the treatment with crude Stevioside, but a similar effect was observed in the placebo group. Therefore, cured Stevioside up to 15.0 mg/kg/day did not show an antihypertensive effect. Moreover, the results suggest that oral crude Stevioside is safe and supports the well-established tolerability during long-term use an as sweetener in Brazil^17-19. Inhibitory effect of Stevioside on calcium influx to produce antihypertension was investigated.

NOW YOU CAN ALSO PUBLISH YOUR ARTICLE ONLINE.

SUBMIT YOUR ARTICLE/PROJECT AT articles@pharmatutor.org

Subscribe to PharmaTutor Alerts by Email

FIND OUT MORE ARTICLES AT OUR DATABASE

Anti-Inflammatory and Immunomodulatory Activities of Stevioside and Its Metabolite Steviol
S. rebaudiana bertoni possesses anti-inflammatory and antitumor promoting properties; however, not much information was available to explain its activity. Stevioside at 1mm significantly suppress lipopolysaccharide (LPS) - induced release of INF- alpha, Interleukin (IL)-1beta slightly suppressed nitric oxide release in THP-1 cells without exerting any direct toxic effect, whereas Steviol at 100μM did not. Activation of I kappa B kinases (IKK) beta and transcription factor NF-kappa B were suppressed by Stevioside as demonstrated by Western blotting.

This study suggested that Stevioside attenuates synthesis of inflammatory mediators in LPS- stimulated THP-1cells by interfering with the IKK beta and NF- kappa B signaling pathway and Stevioside–induced TNF-alpha secretion is partially mediated through TLR4 ²⁰.

Effect of Stevioside on Cardiovascular System
IsoSteviol is a derivative of Stevioside, a constituent of S. rebaudiana, which is commonly used as a non- caloric sugarsubstitute in Japan and Brazil.The study was conducted on rat: cultured rat aortic smoothmuscle cells which were pre incubated with isoSteviol, thenstimulated with angiotensin II, followed by [(3) H] thymidineincorporation and endothelin-1 Secretion was examined.IsoSteviol (1-100micromol/l) inhibits angiotensin-II-inducedDNA synthesis and endothelin-1secertion.Measurement of 2’7’-dichlorofluorescin diacetate, a redoxsensitive fluorescent dye, showed an isoSteviol-mediatedinhibition of intracellular reactive oxygen species generated bythe effects of angiotensin II. The inductive properties of angiotensin II on extra cellularsignal-regulated kinase (ERK) phosphorylation were foundreversed with isoSteviol and antioxidants such as Nacetylcysteine.In conclusion this study speculates that isoSteviol inhibitsangiotensin-II-induced cell proliferation and endothelin-1secretion via attenuation of reactive oxygen species generation.Thus, this study provides important insights that maycontribute to the effects of isoSteviol on the cardiovascular system²¹.

Effect on carbohydrate metabolism
In isolated perfused rat liver stevioside inhibit transport of monosaccharide i.e. glucose fructose and galactose in both the direction. It halves transport rate of glucose into liver and also inhibits hepatic release of glucose. In hamsters fed stevioside for 12 weeks, glucose absorption was found to inhibit by leading to decreases in the body weight of hamster. Oral administration of stevioside (7% of diet) in rats for 56 days caused no change in blood sugar level. However an increase in plasma glucose level was found when stevioside was given intravenous infusion. The magnitude of effect of intake of stevioside on blood glucose level in vivo is still under investigation and there are reports indicating decrease in the blood glucose level and hepatic glucose level in rats after four weeks and in human volunteers eight hours after consumption of extract.

Hemodynamic Effects
According to a 4-week study by Maki et al. (2008), 1,000 mg/day rebaudioside Adid not significantly alter resting, seated systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, or 24-hour ambulatory blood pressure responses in patients with low-normal to normal blood pressure compared with a placebo. 1,000 mg/day is 7-10 times the predicted average daily intake and 2-4 times the daily intake for high intake consumers. A secondary analysis noted small changes in diastolic blood pressure and mean arterial pressure. The investigators assert that those findings are clinically insignificant ²².

Conclusion with future prospects
The leaves of this splendid plant are 30 times sweeter than sugar; with zero calories where as pure extract is 300 times sweeter than sugar. This sweet-honey -leaf herb is likely to become the major source of high potency sweetener for the growing natural food market, in the years to come. Stevia finds its use as a natural sweetener, replacing the chemical sweeteners and even table sugar; the sweetness in leaf is due to the presence of an intensive-sweetening agent called stevioside and the leaf by itself is about 20 to 30 times sweeter than sugar. The leaf has stevioside of 10-12% on dry weight basis. Stevia is a new promising renewable raw material for the food market. The market potential for this natural sweetener is steel untapped. It is estimated that about 30 million Indians are presently suffering from diabetes and it is estimated that by 2025 India’s contribution to the diabetic global population would be a whopping 89 million. With such a huge share of the population being diabetic, the new ventures in the food industry are focused entirely on them.

There is growing international market for Stevia as well as. There are offers to buy container loads of Stevia leaves at a price of 25 dollars per kilo. As mentioned earlier international demand are only for high quality Stevia leaves having minimum 9% Stevioside content. There is no buyer for Stevia leaves having less than 8% Stevioside content. Stevia cultivation can be successful venture provided you are able to produce high quality leaves having minimum Stevioside content of 9% at the same time produce optimum quality of marketable leaves per acre to keep the production cost below Rs. 25 per kilo on five years basis.

The demand for high potency sweeteners is expected to increase Worldwide. The increasing in the number of diabetic patients and health conscious individuals would push forward the need for alternatives to sugar. Stevia is a potential alternative source for replacing artificial sweeteners like saccharin, aspartame, asulfam, etc. Unlike many low calorie sweeteners, stevioside is stable at High temperature and over a pH range of 3 -9. Steps need to be properly aligned to exploit the natural sweetness of Stevia.

It’s time to streamline necessary forces to have access to Stevia. Initiative needs to be undertaken to promote this natural sweetener and create product awareness. This would be the right approach to unlock the sweetness of this herb in our day to-day life.

Acknowledgement
Authors are thankful to Head, department of Pharmaceutical Science, V.N.S. Institute of Pharmacy, Bhopal (M.P.) for providing necessary facilities.

References:
1.    Pinheiro MVS, Oliveria MV et al. Low calorie sweeteners and health; IFIC Review, Washington. Anonymous. 2000; 1-12.  
2.    Dietary Supplement Health and Education Act of 1994. fda.gov. 2011.
3.    Midmore J.D., Rank A.H.; An intense natural sweetener-laying the ground work for a new rural industry; 2006. RIRDC Publication No 06/020.
4.    Dzyuba OO. Stevia rebaudiana (Bertoni) Hemsley -A New Source of Natural Sugar Substitute for Russia. Rastitel Nye Resursy. 1998; 34(2): 86-95.
5.    Gvasaliya VP, Kovalenko M.C et al. Studies on the Possibility of Growing Honey Grass in Abkhazia conditions. Subtropiches kie Kul Tury. 1990; 5: 149-156.
6.    Shu S. Stevia Rebaudiana Variety Trails. Zuocou Pinzhong Ziyuan. 1989; Vol 1; 17-18.
7.    Shock CC. Rebaudi’s Stevia: Natural Noncalorie Sweeteners. California Agriculture. 1982; 36(9): 4-5.
8.    Zdemir & Sadikoglu. Characterization of Rheological properties of systems containing sugar substitutes & carrageenam. International Journal of food Science and Technology. 1998; 33: 439-444.
9.    Kinghorn AD, Kaneda N, Baek NI et al. Non-Cariogenic intense natural sweeteners. Inc. Med. Res. Rev. 1998; 18(5): 347- 360.
10.    Antonie Al-Achi. Stevia: A plant for sweetness; U.S.Pharmacist- a Johnson publication. 2000; 25: 9-16.
11.    Mindore DJ, Rank AM. RIRDC (Rural Industries Research Development Corporation) publication Australia and New-Zealand; August 2002 report.
12.    Elkins R. Stevia-Nature’s sweet; woodland publication. 1999.
13.    Combined Compendium of Food Additive Specifications; Tentative specification prepared at sixty third JECFA meeting; Published in FNP 52 Add 12; 2004.
14.    Gregersen S, Jeppesen PB, Holst JJ, Hermansen K et al. Antihyperglycemis effect of Stevioside in Type 2 Diabetic Subjects.  Metabolism. 2004; 53 (1): 73-76.
15.    Gougeon R, Spidel M. Canadian Diabetes Association national Nutrition Committee Technical Review: on nutritive intense sweeteners in Diabetes management. Canadian Journal of diabetes. 2004; 28(4): 385-399.
16.    Chen J, Jeppesen PD. Stevioside does not cause increased Basel insulin secretion or beta cell desensitization as does the sulphonylurea, glibenclancida: studies in vitro. Journal of Life Sciences. 2006; 78: 1748-1753.
17.    Ferri LAF, Alves WP et al. Investigation of the antihypertensive effect of oral crude Stevioside in patients with mild essential hypertension. Phytotherapy Research. 2006; 20: 732-736.
18.    Boonkaewwan C, Toskulkao C, Vongsakul M. Antihypertensive and Immunodulatory activities of Stevioside and its metabolite Steviol on THP-1 cells. Journal Agriculture Food Chemistry. 2006; 54(3): 785-789.
19.    Wong KL, Lin JW, Liu JC et al. Antiproliferative effect of isoSteviol on angiotensin-II-treated rat arotic smooth muscle cells. Pharmacology. 2006; 76(4): 163-169.
20.    Oveido CA, fronciana G, Moreno R and mass LC. acute hypoglycemic activity of stevia rebaudiana. Expert Medica. 1970; 209: 92-98.  
21.    Saunarunsawat T and chaiyabutr N. effect of stevioside on glucose metabolism in rat. can j physiol Pharmacol. 1975; 75: 976-982.
22.    Maki KC, Curry LL, Carakostas MC. et al. The hemodynamic effects of rebaudioside A in healthy adults with normal and low-normal blood pressure. Food and Chemical Toxicology. 2008; 46: 40–46.

NOW YOU CAN ALSO PUBLISH YOUR ARTICLE ONLINE.

SUBMIT YOUR ARTICLE/PROJECT AT articles@pharmatutor.org

Subscribe to PharmaTutor Alerts by Email

FIND OUT MORE ARTICLES AT OUR DATABASE