Hydrogen Peroxide-Induced Steviol Glycosides Accumulation and Enhancement of Antioxidant Activities in Leaf Tissues of Stevia rebaudiana Bertoni

Abstract

Hydrogen peroxide (H2O2) functions as an abiotic stress elicitor for plants. In this study, the effect of oxidative stress caused by H2O2 on steviol glycosides (SGs) production and antioxidant activities of an in vitro grown antidiabetic plant, Stevia rebaudiana, has been investigated. Direct shoot organogenesis was performed, and after 4 weeks of culture, the shoots of S. rebaudiana were transferred to MS medium containing H2O2 (10 or 20 mM) and incubated in growth room for 6 h. It resulted in increased SGs production, such as rebaudioside A (Reb-A) and stevioside (ST), and enhancement of total phenolic content, total flavonoid content, total antioxidant capacity, total reducing power and DPPH free radical scavenging activity when compared with control. The results clearly showed highest amount of SGs produced in MS medium containing 10 mM H2O2 [producing 2.97% Reb-A and 2.32% ST (w/w)], followed by the medium employing 20 mM H2O2 and control group. It is also evident that H2O2 pre-treatment caused significant increase in non-enzymatic antioxidants that play defensive role against an oxidative stress induced by H2O2. The described protocol has a great potential to be utilized for Reb-A production on commercial scale.