Glucosylation of steroidal saponins by cyclodextrin glucanotransferase.
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.
Wang
Yong-ze
YZ
Beijing Institute of Radiation Medicine, Beijing, People's Republic of China.
Feng
Bing
B
Huang
Hong-zhi
HZ
Kang
Li-ping
LP
Cong
Yue
Y
Zhou
Wen-bin
WB
Zou
Peng
P
Cong
Yu-wen
YW
Song
Xin-Bo
XB
Ma
Bai-ping
BP
D027882:Agave / Q000737:chemistry; D031403:Anemarrhena / Q000737:chemistry; D003603:Cytotoxins / Q000494:pharmacology; D005964:Glucosyltransferases / Q000737:chemistry*; D018922:HL-60 Cells; D006801:Humans; D019684:Magnoliopsida / Q000737:chemistry; D012503:Saponins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D013379:Substrate Specificity
D003603:Cytotoxins; D012503:Saponins; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase