Radical scavenging activity of steviol glycosides, steviol glucuronide, hydroxytyrosol, metformin, aspirin and leaf extract of Stevia rebaudiana

Abstract

a b s t r a c tIntroduction: Reactive oxygen species (ROS), generated in many bioorganic redox processes, are the most dangerous by-products in the aerobic environment. The aim of this study was to compare the in vitro antioxidant activity of some chemical compounds and leaf extract of Stevia rebaudiana as natural antioxidant. Methods: The radical scavenging activity of ascorbic acid, quercetine, stevioside (ST), rebaudioside A (Reb A), steviol glucuronide (SVglu), glucose, sucrose, hydroxytyrosol, metformin and aspirin were measured and expressed as the inhibitory concentration in mM giving 50% reduction of radicals (IC 50 ). Results: Ascorbic acid, quercetine, ST, Reb A, SVglu, glucose, sucrose, hydroxytyrosol, metformin and aspirin were active OH scavengers. Superoxide radicals were efficiently scavenged by ascorbic acid, SVglu, quercetine, hydroxytyrosol, ST, Reb A and aspirin. Quercetine, hydroxytyrosol, ascorbic acid and aspirin were active in limiting the amount of thiobarbituric acid (TBA) reactive material. Only ascorbic acid, quercetine and hydroxytyrosol showed DPPH and NO scavenging activity. Leaf extract of S. rebaudiana had an excellent ROS scavenging activity. Treatment of leaf extracts with PVPP and active charcoal removed a part of their scavenging activity. Results showed that sugars were not efficient ROS scavengers. Conclusion: Radical scavenging activity of steviol derivatives, aspirin, metformin and hydroxytyrosol might explain most of beneficial pharmacological effects on ROS related diseases, such as hypertension, type 2 diabetes, atherosclerosis, inflammation and certain forms of cancers. The results obtained in this study indicate that leaf extract of S. rebaudiana has a great potential to use as a natural antioxidant agent.

Study ofStevia rebaudianaBertoni antioxidant activities and cellular properties

“…The efficacy of the extracts from the leaves was higher than that of stems, while the capacity of stevioside and rebaudioside A, the most abundant sweeteners found in stevia, was much lower through ORAC (ranging from 2.1-10.7%). Furthermore, these data confirm the previous findings from Hajihashemi group (Hajihashemi & Geuns, 2013), who also found a better ROS scavenging capacity for crude extracts.…”

Stability of the Stevia‐Derived Sweetener Rebaudioside A in Solution as Affected by Ultraviolet Light Exposure

“…Literature sources about Fe(III)‐photocatalysis indicated citric acid can combine with iron to form Fe(III)‐citrate complexes, which can photo‐oxidize under UV light to generate HO• (Wu and Deng ; Chen and others ). Rebaudioside A has been reported to be an excellent HO• scavenger (Hajihashemi and Geuns ). It is hypothesized that the HO• generated from Fe(III)‐citrate complex can accelerate the degradation of rebaudioside A.…”

Reduction of the Oxidative Stress Status Using Steviol Glycosides in a Fish Model(Cyprinus carpio)

“…A study conducted by Hajihashemi and Geuns [58] hypothesized that, due to the high content of sugars present in the SGs, these presented their high antioxidant capacity; however, the results showed that this did not occur.…”