In vitro: |
Food Chem Toxicol. 2014 Apr;66:334-40. | The non-cytotoxicity characterization of rebaudioside A as a food additive.[Pubmed: 24500608] | To evaluate the cytotoxicity of high-purity rebaudioside A (reb A, 99.16%) as a food ingredient, a combination of several methods, including tetrazolium-based colorimetric assay (MTT), lactate dehydrogenase assay (LDH), enzyme-linked immunosorbent assay (ELISA), real-time PCR (qPCR), high-performance liquid chromatography (HPLC), and two-dimensional electrophoresis (2-DE) were used to test the cytotoxicity of rebaudioside A on the human cells HT-29 and T84, as well as liver and spleen cells from mice. The results indicated that no obvious changes in cellular viability, inflammatory cytokines yield, or protein yield were observed between the test group and the control group when different concentrations of rebaudioside A were used, suggesting that rebaudioside A is non-cytotoxic in vitro at the concentrations range tested (0.001-0.5%). | Food Chem . 2016 Jun 1;200:154-8. | Synthesis of rebaudioside-A by enzymatic transglycosylation of stevioside present in the leaves of Stevia rebaudiana Bertoni[Pubmed: 26830573] | Abstract
Rebaudioside-A is the second most abundant sweet diterpene glycoside (1-3%) present in the leaves of Stevia rebaudiana Bertoni, and is now being considered as a possible sucrose substitute due to its pleasant organoleptic properties and associated health benefits. In the present study, a novel in situ enzymatic transglycosylation of stevioside has been developed by pre-treating the stevia leaves with cellulase and adding soluble starch as the glucosyl donor. The results confirm that the transglycosylation of stevioside led to an enrichment in the rebaudioside-A content from 4% to 66%. This was further purified by multiple column chromatography to obtain 95% pure rebaudioside-A. The isolated rebaudioside-A showed concentration-dependent α-glucosidase inhibitory activity with IC50=35.01 μg/ml. Thus the study highlights the biotransformation of stevioside present in stevia leaves to rebaudioside-A by a simple, inexpensive and eco-friendly process that has commercial potential.
Keywords: Cellulase; Glucosyl donors; Rebaudioside-A; Rebaudioside-A (PubChem CID:6918840); Stevia leaves; Stevioside (PubChem CID:442089); Transglycosylation. |
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