Abstract

Stevioside is a natural non-caloric sweetener refined from Stevia rebaudiana Bertoni leaves. The introduction of stevioside as a sugar substitute in the diets of diabetics and others on carbohydrate-controlled diets has been suggested, but safety issues have prevented implementation. The aim of this study was to examine antioxidant status changes in the sera, livers and kidneys of young male rats fed with low doses of stevioside (SL) or high doses of stevioside (SH) for 12 weeks. We investigated oxidative stress biomarkers such as the levels of reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS), the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR). Our results show that SH treatment causes significant induction of TBARS in liver and kidney, accompanied by a significant reduction in SOD, CAT, GR and GSH levels in the same organs. SL treatment causes insignificant changes in SOD and CAT, but significant reduction was observed in GR, GSH and TBARS in serum and all tested organs when compared with the control. In conclusion, features of oxidative stress were detected in the liver and kidney of young male rats treated with SH for 12 weeks, whereas no significant changes in SOD and CAT were detected after SL treatment.

Key words: Stevioside, safety of natural sweeteners, food safety, oxidative markers.

Abbreviation

SL, Low doses of stevioside; SH, high doses of stevioside; GSH, reduced glutathione; GR, glutathione reductase; SOD, superoxide dismutase; CAT, catalase,

TBARS, thiobarbituric acid reactive substances.