Stevia Rebaudiana Bert. Leaf Extracts as a Multifunctional Source of Natural Antioxidants

Abstract

The aim of the presented study was to characterize the content and biological activity of extracts prepared from dried Stevia rebaudiana leaves with potential application in the food or cosmetic industry. Aqueous (A), ethanolic (E) and glycol-aqueous (GA) extracts were analyzed for the content of polyphenols and proteins, showing that the highest amount of phenols (15.50 mg/g) and flavonoids (3.85 mg/g) contained GA. All extracts contained significant amount of protein (69.40–374.67 mg/g). Between analyzed stevia extracts (HPLC) GA contained the highest amount of polyphenols, especially ferulic (5.50 mg/g) and rozmaric (4.95 mg/g) acids derivates. The highest antiradical activity against DPPH• and ABTS•+ was noted for GA and E (IC50 = 0.38 and 0.71 µg flavonoids/mL). The highest ability to chelate Fe2+ was observed for E (IC50 = 2.08 µg flavonoids/mL). Stevia extracts were also analyzed for their cytotoxicity and fibroblast irritation potential in vitro. E and GA were the most cytotoxic and irritating, probably due to the high content of biologically active phytochemicals. On the other hand, a extract was the most tolerable by the cells. To summarize, the presented study evaluated the potential application of A, E and GA stevia extracts as natural source of antioxidants in the food and cosmetic industry.

New seminal variety of Stevia rebaudiana: Obtaining fractions with high antioxidant potential of leaves

“…Shukla et al 2009 found 61.5 mg/g GAE from the ethanol extract of Stevia leaves through Soxhlet. Gawel-Beben et al 2015 found similar values of phenolic compounds in ethanol extract of dried leaves from Stevia rabaudiana. The values found in the present study indicate that these compounds should be further evaluated for their antioxidant potential in food and drinks, and further demonstrates that the ethyl acetate fraction has the greatest potential for will provide additional benefits in terms of oxidative.…”

“…Stevia UEM-13 therefore presented a ratio RebA/Stev much higher (2.27) than the wild varieties that have inferiors values to 1 (Kovylyaeva et al 2007, Gardana et al 2010, Gupta et al 2013, Madan et al 2010. The new cultivar has significant levels of bioactive compounds when compared with other wild varieties (Gawel-Beben et al 2015, Pasquel et al 2000, Wölwer-Rieck 2012.…”

“…The beneficial effects of these compounds on human health have been previously studied. Research aimed at obtaining Stevia extracts containing significant levels of sweeteners and these compounds (Gawel-Beben et al 2015, Kawshik et al 2010. The results showed that there is still no consensus on the ideal method of obtaining both compounds (sweeteners and bioactive compounds) in significant concentrations.…”

Stevia‐fortified yoghurt: Stability, antioxidant activity and in vitro digestion behaviour

“…Concerning the growing trend in the use of plant extracts in the food and beverage industry, the use of stevia from Stevia rebaudiana Bertoni plays a significant role (Gaweł‐Bȩben et al . ). Stevia is a natural sweetener whose commercial importance is linked to the purified steviol glycosides extracted from the plant's leaves, which are noncaloric molecules that have a high sweetening potential (Giri et al .…”

“…The therapeutic effects associated with consumption of stevia leaves and their crude extracts include antimicrobial, antihypertensive, antihyperglycaemic and immunoregulatory effects, all of which have been linked to the bioactive phytoconstituents of stevia leaves (Wölwer‐Rieck ; Gaweł‐Bȩben et al . ).…”