Stevia is a sweet sugar substitute, extracted from the leaves of the plant species Stevia rebaudiana (Fam. Asteraceae). Stevia rebaudiana Bertoni is a branched bushy shrub, a perennial herb that grows in Brazil and Paraguay. It is often referred to as sweet herb, honey leaf, honey yerba and candy leaf.
Constituents
The active compounds are steviol diterpene glycosides (mainly stevioside and rebaudioside), which have about 50 to 300 times the sweetness of sugar. Stevia leaves also contain proteins, carbohydrates, lipids, dietary fibres, oils, vitamins, and phenolic compounds.
The dry extract from the leaves of stevia contains flavonoids, alkaloids, water-soluble chlorophylls and xanthophylls, hydroxycinnamic acids (caffeine, chlorogenic, etc.), potassium, calcium, magnesium, and sodium , folic acid, niacin, vitamins B1, B2, B6, C.
Preparations
Stevia is used in different forms, such as fresh and dried Stevia leaves, Stevia leaf powder, extracts, granules, tablets and liquid concentrates. Stevia is used for sweetening creamy desserts, drinks, fruit, salad dressings, yogurt and tea.
Pharmacological actions and medicinal uses
The human body does not metabolise the glycosides in stevia; so it contains zero calories as a non-nutritive sweetener. Its taste has a slower onset and longer duration than that of sugar, and, at high concentrations, some of its extracts may have an aftertaste described as licorice-like or bitter.
Stevia leaves have been reported to be used traditionally in Paraguay as a women’s contraceptive. Studies further reveal that Stevia leaves contain many biologically active substances, which have anti-diabetic, antihypertensive, antitumor, anti-cariogenic, anti-inflammatory and bactericidal effects.
Studies have also shown the protective effects of Stevia on the digestive system and skin disorders, as well as on common complications associated with metabolic syndrome. Stevia contains caffeic acid, flavonoids, kaempferol, quercetin, tannins and triterpenes that enable the body to fight free radicals that can damage cells and contribute to cancer, heart disease and other health concerns.
Studies have shown that stevia significantly lowered insulin and glucose levels. Some evidence suggest that stevia may help fight or prevent some types of cancer by boosting cancer cell death and decreasing some mitochondrial pathways that help cancer grow.
Stevia does not have the neurological or renal side effects that other artificial sweeteners have. Stevia possesses anti-fungal and anti-bacterial properties. Mild stevia leaf tea offers excellent relief for an upset stomach.
Adverse effects
There is concern that raw stevia herb may harm the kidneys, as well as the reproductive and the cardiovascular systems. It may cause blood pressure to drop too low or interact with medications that lower blood sugar.
There have also been warnings that steviol at high dosages may have weak mutagenic activity. In some people, stevia products made with sugar alcohols may cause digestive problems, such as bloating and diarrhoea.
Economic uses and potentials: Stevia is useful in the pharmaceutical, food and beverage industries. Stevia sweeteners are used in a wide range of food and beverage applications including soft drinks, candies, chocolate, chewing gum, ice cream, yogurt, jam, pudding, and table-top sweeteners. Stevia costs about N3,000 naira per pack of 10 seeds, N1,000 per seedling, N10,000 per 100g refined powder. Global demand for stevia is estimated at N13 trillion/year. Stevia has the potential to create jobs for Nigerians in through cultivation, processing, manufacturing, research, distribution, sales and exportation.
References
Olatoye K. (2019). Stevia: The untapped goldmine in Nigeria. Agriculture reading time. The Nigerian Tribune. September 19. Available at: https://tribuneonlineng.com/stevia-the-untapped-goldmine-in-nigeria/#:~:text=Stevia%20plant%20grows%20best%20in,its%20best%20growth%20and%20yield.
Khiraoui A., Hasib A., Al Faiz C, Amchra F., Bakha M. and Boulli A. (2017). Stevia Rebaudiana Bertoni (Honey Leaf): A Magnificent Natural Bio-sweetener, Biochemical Composition, Nutritional and Therapeutic Values. Journal of Natural Sciences Research. 7(14).
By Pharm. Ngozika Okoye MSc, MPH, FPCPharm
(Nigeria Natural Medicine Development Agency)
Email: ngozikaokoye@yahoo.com
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