The leaves of Stevia rebaudiana (Bertoni), their constituents and the analyses thereof: a review.

The plant Stevia rebaudiana is well-known due to the sweet-tasting ent-kaurene diterpenoid glycosides. Stevioside and rebaudioside A are the most abundant and best analyzed, but more than 30 additional steviol glycosides have been described in the scientific literature to date. Most of them were detected in the last two years. This paper reviews these new compounds and provides an overview about novel trends in their determination, separation, analysis, detection, and quantification. The detection and analysis of further constituents such as nonglycosidic diterpenes, flavonoids, chlorogenic acids, vitamins, nutrients, and miscellaneous minor compounds in the leaves of Stevia rebaudiana are reviewed as well. A critical review of the antioxidant capacity of Stevia leaves and its analysis is also included. These different aspects are discussed in consideration of the scientific literature of the last 10 years.