Introduction:
The sweet herb of Paraguay, Stevia rebaudiana leaves is an indigenous sweetener, a gift of nature, an alternative to artificial sweetening products. In addition, Stevia leaves have functional and sensory properties superior to those of many other high potency sweeteners. Stevia is likely to become a major source of high potency sweetener for the growing natural food market in the future. Stevia can be advantageous to practically everyone whose diet contains sweeteners. Although Stevia can be helpful to anyone, there are certain groups who are more likely to benefit from its remarkable sweetening potential. These include diabetics, those interested in decreasing caloric intake, and children.

Plant Description: Stevia rebaudiana is a small shrubby perennial growing up to 65-80 cm tall, with sessile, oppositely arranged lanceolate to oblancoelate leaves, serrated above the middle. Trichome structures on the leaf surface are of two distinct sizes, one large (4-5 µm), one small (2.5 µm). The flowers are small (7-15 mm), white and arranged in an irregular cyme. The seed is an achene with a feathery pappus. Stevia is diploid and has 11 chromosome pairs, which is characteristic for most of the South American members of the genus. Different species of Stevia contain several potential sweetening compounds, with Stevia rebaudiana being the sweetest of all.

Habitat:
Stevia extends from the southwestern United States to the Brazilian highlands. Stevia is a semi-humid subtropical plant that can be grown easily like any other vegetable crop even in the kitchen garden. The plant reaches a height of 45 cm in three months and is a short day plant. The concentration of stevioside in the leaves of Stevia increases when the plants are grown under long day condition. While, cultivating Stevia on a large scale, it can be grown in well-drained red soil and sandy loam soil. The soil should be in the pH range of 6.5- 7.5. Saline soils should be avoided to cultivate this plant.

Distribution:
Stevia is not an indigenous herb of India and neither there has been any description of Stevia plant or its property and traditional uses in Ayurveda Text. Stevia is a subtropical plant with vegetative propagation hence has been successfully cultivated in the recent years at many areas of Rajasthan, Maharashtra, Kerela and Orissa. The increasing demands for natural sweetners have driven the farmers in India for Stevia cultivation in large scale.

History:
Stevia rebaudiana is one of 154 members of the genus Stevia and one of only two that produce sweet steviol glycosides. Stevia was first brought to the attention of Europeans in 1887 when M.S. Bertoni learned of its unique properties from the Paraguayan Indians and Mestizos. The leaves were used either to sweeten maté or as a general sweetening agent. The first reports of commercial cultivation in Paraguay were in 1964. A large effort aimed at establishing Stevia as a crop in Japan was begun by Sumida in1968. Since then, Stevia has been introduced as a crop in a number of countries including Brazil, Korea, Mexico, United States, Indonesia, Tanzania, Canada and now in India since 8-10 years.

Chemical composition:
DITERPENE GLYCOSIDE is the group of natural sweeteners that have been extracted from Stevia. Studies have led to the isolation of seven sweet glycosides till date. Four major lycosides found in the leaves of wild Stevia plants is 0.3 % dulcoside, 0.6% rebaudioside C, 3.8 % rebaudioside A and 9.1 % stevioside.

Action:
Stevia is used in many parts of the world as a non-caloric sweetener. Along with sweetness, a bitter taste is also noted in humans. As an extract, this herb was found to have similar potency with regard to sweetness as a 10% sucrose solution at either pH 3.0 or 7.0. The same study also showed that the herbal extract had similar potency as that of aspartame and a cyclamate/saccharin mixture.

Uses:

• Stevia has no calcium cyclamate, no saccharin, no aspartame, and no calories.
• Stevia is safe for diabetics, as it does, not affect blood sugar levels.
• Stevia does not have the neurological or renal side effects of some of the artificial sweeteners.
• Stevia possess anti-fungal and anti-bacterial property also in addition to its other versatile uses. It can be safely used in herbal medicines, tonics for diabetic patients and also in the daily usage products like mouthwashes, and tooth pastes.
• Mild Stevia leaf tea offers excellent relief for an upset stomach.
• Stevia tea helps to reduce the desire for tobacco and alcoholic beverages.
• A wet Stevia leaf bag provides a cooling effect on eyes (similar to using cucumber). The leaves effectively tighten the skin and are good for wrinkles. Stevia has proved to give exceptional benefits when used regularly in skin care.
• Stevia also has a healing effect on blemishes, wounds, cuts and scratches.
• Stevia is helpful in weight and blood pressure management. It has also been reported that Stevia lowers incidence of colds and flu.