Steviol

Steviol is a diterpene compound that serves as the aglycone of steviol glycosides, most notably stevioside and rebaudioside A, which are the principal sweetening components of the leaves of Stevia rebaudiana. The plant, native to South America and now cultivated worldwide, produces these glycosides in its leaves as part of its secondary metabolism. The steviol molecule is a hydroxylated kaurane-type diterpene; the sweetness of commercial steviol glycosides arises from the sugar moieties attached to the steviol aglycone.

In natural and commercial contexts, steviol glycosides are responsible for the intense sweetness of Stevia extracts, but steviol itself is not used as the sweetener. After ingestion, steviol glycosides pass through the upper digestive tract largely without hydrolysis. In the colon, gut microflora hydrolyze the glycosides to steviol, which is absorbed and transported to the liver, where it is conjugated to steviol glucuronide. The conjugate is excreted mainly in urine, with minimal metabolism of the aglycone elsewhere. This metabolic fate underpins their low caloric value and informs regulatory assessment.

Regulatory status: Steviol glycosides have been approved for use as non-nutritive sweeteners in numerous jurisdictions. The established acceptable daily intake is 0 to 4 milligrams per kilogram of body weight per day, expressed as steviol equivalents, based on evaluations by JECFA and EFSA. In the United States, the FDA has recognized steviol glycosides as safe for use in foods under their GRAS status.