It is known that the sugar chains of steroidal saponins play an important role in the biological and pharmacological activities. In order to synthesize steroidal saponins with novel sugar chains in one step for further studies on pharmacological activity, we here describe the glucosylation of steroidal saponins, and 5 compounds, timosaponin AIII (1), saponin Ta (2), saponin Tb (3), trillin (4) and cantalasaponin I (5), were converted into their glucosylated products by Toruzyme 3.0 L, a cyclodextrin glucanotransferase (CGTase). 12 glucosylated products were isolated and their structures elucidated on the basis of spectral data; they were all characterized as new compounds. The results showed that Toruzyme 3.0 L had the specific ability to add the α-D-glucopyranosyl group to the glucosyl group linked at the sugar chains of steroidal saponins, and the glucosyl group was the only acceptor. This is the first report of steroidal saponins with different degrees of glucosylation. The substrates and their glucosylated derivatives were evaluated for their cytotoxicity against HL-60 human promyelocytic leukemia cell by MTT assay. The substrates all exhibited high cytotoxicity (IC(50) < 10 µmol/L), excluding compound 5 (IC(50) > 150 µmol/L), and the cytotoxicity of most of the products showed no obvious changes compared with those of their substrates.
BackgroundRadix isatidis (Isatis indigotica Fort.) is an ancient medicinal herb, which has been applied to the prevention and treatment of influenza virus since ancient times. In recent years, the antioxidant activity of Radix isatidis has been widely concerned by researchers. Our previous studies have shown that Radix isatidis protein (RIP) has good antioxidant activity in vitro. In this study, the composition of the protein was characterized and its antioxidant activity in vivo was evaluated.MethodsThe model of oxidative damage in mice was established by subcutaneous injection of D-galactose for 7 weeks. Commercially available kits were used to determine the content of protein and several oxidation indexes in different tissues of mice. The tissue samples were stained with hematoxylin and eosin (H&E) and the pathological changes were observed by optical microscope. The molecular weight of RIP was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The amino acid composition of RIP was determined by a non-derivative method developed by our research group.ResultsRIP significantly increased the activities of antioxidant enzymes such as SOD, CAT, GSH-Px and total antioxidant capability (TAOC) but decreased the MDA level in the serum, kidney and liver. H&E stained sections of liver and kidney revealed D-galactose could cause serious injury and RIP could substantially attenuate the injury. The analysis of SDS-PAGE showed that four bands with molecular weights of 19.2 kDa, 21.5 kDa, 24.8 kDa and 40.0 kDa were the main protein components of RIP.ConclusionsThe results suggested that RIP had excellent antioxidant activity, which could be explored as a health-care product to retard aging and a good source of protein nutrition for human consumption.
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