Transglycosylation is one of enzymatic methods to improve the physical and biochemical properties of various functional compounds. In this study, stevioside glucosides were synthesized using sucrose as a substrate, stevioside (Ste) as an acceptor, and dextransucrase from Leuconostoc mesenteroides B-512 F/KM. The highest Ste conversion yield of 98% was obtained with 50 mg/mL Ste, 800 mM sucrose, and dextransucrase 4 U/mL at 28 °C for 6 h. The concentration of Ste was unchanged while of Ste-G1 was increased from 7.7 mM to 9.1 mM as the Ste acceptor reaction digest was treated with dextranase from Lipomyces starkeyi. Ste-G1 (13-O-β-sophorosyl-19-O-β-isomaltosyl-steviol), Ste-G2 (13-O-(β-(1→6) glucosyl)-β-glucosylsophorosyl-19-O-β-isomaltosyl-steviol), and Ste-G2′ (13-O-β-sophorosyl-19-O-β-isomaltotriosyl-steviol) were determined by NMR. These glucosylated Ste showed increased stabilities at pH 2, 60 °C for 48 h as compared to Ste. Ste-G1, Ste-G2, and Ste-G2′ inhibited the insoluble glucan synthesis from sucrose by mutansucrase from Streptococcus muntans by the transfer of the glucosyl group of sucrose to Ste-G1, Ste-G2, and Ste-G2′. The relative water solubility of curcumin, pterostilbene or idebenone was increased by Ste or Ste glucosides treatment. Ste and Ste-G1 restored cell viability in RAW264.7 cells at concentrations up to 8 mg/mL and inhibited nitric oxide production in LPS-induced RAW264.7 cells with IC50 of 3.29 and 1.87 mg/mL.
Bibliographical noteFunding Information:
This work was partially supported by the OTTOGI Corporation through the Research and Publication Project, by the Korean Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry, and Fisheries (IPET) through the Agriculture, Food and Rural Affairs Research Center Support Program, funded by the Ministry of Agriculture, Food, and Rural Affairs (MAFRA) (D. Kim, 710012-03-1-HD220), Republic of Korea. The present study has been also conducted under the framework of International Cooperation Program (2016K1A3A1A19945059), and by the research grants (2018R1D1A1B07049569, T.T.H. Nguyen, 2018R1D1A1A09083366, D. Kim) of NRF, Republic of Korea.
All Science Journal Classification (ASJC) codes
- Applied Microbiology and Biotechnology