Stevia
Stevia rebaudiana
“Stevia rebaudiana Bert. is a strong sweetening agent. The glycosides stevioside and steviol affect several mitochondrial functions. The questionable hypoglycemic effect may be due to inhibition of glucogenesis leading to hypoglycemia (Curi et al, 1986). Stevia’s effect on blood glucose is inconclusive in human studies. Stevia may have antihypertensive effects. Animal studies suggest effectiveness in fertility reduction and diuresis, but few human studies are available. Stevia has also been tested as a spasmolytic, antibiotic, and as an adjunct in vein surgery…
“Pure stevioside has caused bradycardia and hypotension in humans and rats (Melis, 1996). Stevioside’s action on mean arterial pressure and renal function is similar to that of a calcium antagonist such as verapamil (Melis, 1996; Melis & Sainati, 1991). In animal experiments, stevioside significantly elevated the glucose clearance while at the same time increasing both salt excretion and urine flow (measured in percentage of glomerular filtration rate), which led to a significant lowering of blood pressure.
“Stevia leaves (a 5% decoction) reduced fertility in female rats by as much as 65%, but purified stevioside had no effect on pregnancy or rat fetus development (Suttajit et al, 1993). In a controversial study, fertility in rats was decreased by 57% to 79% after administration of a Stevia decoction when compared to rats given water. The decrease occurred across 3 differently treated experimental groups. The reduction in fertility was still evident 50 to 60 days after discontinuation of Stevia (Planas & Kuc, 1968). In a separate study, an infusion of Stevia was tested in a cell cycle test model (Allium cepa meristems) to determine if the mechanism of action involved c-mitotic effects. No adverse effect on the cell cycle was observed with the administration of Stevia suggesting that the contraceptive effects may not be due to changes in the chromosome cycle (Schvartzman et al, 1977).”
- PDR for Herbal Medicine, Fourth edition