Phytochemical and Pharmacological Importance of Stevia: A Calorie-Free Natural Sweetener

Abstract

Stevia, a natural sweetener, comprises of 200 species of herbs and shrubs from the family Asteraceae (Composite). The most common species of this genus and family with sweetening potential are Stevia dianthoidea, S. phlebophylla, S. anisostemma, S. bertholdii, S. crenata, S. enigmatica, S. eupatoria, S. lemmonii, S. micrantha, S. plummerae, S. rebaudiana, S. salicifolia, S. serrata and S. viscida but among these only S. rebaudiana exhibits the highest level of sweetness. It is cultivated in China, Taiwan, Thailand, Korea, Brazil, Malaysia, Canada, Hawaii and California. Rajasthan, Maharashtra, Kerala and Haryana are the main Stevia growing states in India. Stevia contains ent-kaurene, a diterpene glycoside commonly known as stevioside which is 150–300 times than more sweeter sugar. In addition to its interesting sweetening property, Stevia plant shows many pharmacological properties. Its leaves also contains good amount of protein, amino acid, lipids, vitamins and minerals. Phytochemical screening showed that tannins are also present in higher concentrations followed by alkaloids, glycosides, saponins, sterols, and triterpenes, anthraquinones, and other reducing compounds. Stevia glycosides possess many pharmaceutical properties viz; anti-hyperglycemic, antihypertensive, antioxidant, antimicrobial activity, anticancer effect, anti-inflammatory and immune-modulatory effect etc. Stevia has potential qualities of a sweetener and also constituting a source of many substances with a nutritional effect on the human beings. Among different chemical constituents, stevioside has a potential mode of actions in controlling type 2 diabetes. Stevia-enriched food products bring several benefits to human society. Commercial marketing of products stevia in different form such as leaf powder, liquid and fresh leaves has become a potential adventure for many biotechnological companies because of its large demand.