Comparison of some antioxidant properties of plant extracts from Origanum vulgare, Salvia officinalis, Eleutherococcus senticosus and Stevia rebaudiana

Abstract

Phenolic compounds from plants are known for their antioxidant properties and have been proposed as therapeutic agents to counteract oxidative stress. However, under normal circumstances, the body only receives a very small amount of these substances in the diet. We have investigated the effect of extracts from known and frequently used plants as part of diet, food seasoning, medicinal tea, and sweetener at different concentrations on the ability to scavenge free radicals, to affect antioxidant enzymes, and finally in the survival of cancer cell lines. We found extract concentrations of about 100 μg.ml(-1) more indicative in the assessment of all parameters investigated. Ginseng possessed a very good ability to scavenge superoxide and hydroxyl radicals, while stevia also manifested significant effects against hydroxyl radicals. Both extracts also showed NO decomposition ability. The antioxidant defense system against the excessive production of radicals in mitochondria was sufficient. In contrast, the range of operating concentrations for sage and oregano mainly presented no significant effects against reactive oxygen and nitrogen species. Taken together with the significantly reduced activity of glutathione peroxidase, this led to the depletion of glutathione. The demonstrated modulation of redox state capability was sufficient to affect the viability of all tested cancer cell lines, but especially A-549, CEM and HeLa by oregano extract. Results support the promising role of the tested extracts as a source of compounds for further in vivo studies with the ability to powerfully interfere with or modify the redox state of cells according to the type of disease, which is expected to be associated with oxidative stress.

Study ofStevia rebaudianaBertoni antioxidant activities and cellular properties

“…Additionally, we observed that water extracts of stevia leaves and stems did not show significant differences in antioxidant enzyme activities when assayed in terms of catalase activity. Similarly, it was reported elsewhere (Vaško et al, 2014) that after the treatment of liver mitochondria with stevia extracts no significant effect was observed in the superoxide dismutase activity, another key antioxidant enzyme. Thus, the mechanisms of action of stevia's antioxidant capacity seem to be through its ability to directly reduce oxidizing free radicals, rather than a potential to modulate endogenous enzymatic antioxidant systems.…”

Stevia rebaudiana Bertoni: health promoting properties and therapeutic applications

“…Recently anti-neoplastic properties of S. rebaudiana Bertoni compounds have been investigated by some researchers (Mann et al 2014;Vaško et al 2014;Khaybullin et al 2014). Khaybullin et al (2014) found that isosteviol derivatives possess cytotoxic activity on tumor cells derived from primary and metastatic cancer cells.…”

Stevia rebaudiana Bertoni bioactive effects: From in vivo to clinical trials towards future therapeutic approaches

“…Other studies showed similar antioxidant potentialities (Hajihashemi & Ehsanpour, 2014;Ruiz-Ruiz et al, 2015;Zayova, Stancheva, Geneva, Petrova, & Dimitrova, 2013). Vaško, Vašková, Fejerčáková, Mojžišová, and Poráčová (2014) reported that stevia has significant effects against hydroxyl radicals and has ability to decompose NO. Additionally, the antioxidant defense system against the excessive free radical production in mitochondria was satisfactory, confirming its strong ability to affect the cells redox state (Vaško et al, 2014).…”