Efficient synthesis of glycyrrhetinic acid glycoside/glucuronide derivatives using silver zeolite as promoter

Biosynthesis of Glycyrrhetinic Acid-3-O-monoglucose Using Glycosyltransferase UGT73C11 from Barbarea vulgaris

“…This result is higher than that of the chemical glycosylation of GA in the literature. For example, GA-glycoside derivative was prepared in 65% yield using glycosyl bromide donors and silver zeolite as catalyst which was performed in dichloromethane with 4 Å molecular sieves at room temperature after 4 days . Monodesmosidic GA-glycoside was synthesized with the maximum yield of 62% by applying trifluoromethanesulfonate (TMSOTf) as promoter at −70 °C and 2 h stirring .…”

“…For example, glycyrrhizin (GL) and glycyrrhetinic acid monoglucuronide (GAMG) are two glycosylated GA derivatives with glucuronidic acids. The two GA-glycoside derivatives are not only more soluble than GA but also present special sweetener tastes and widely pharmacological activities. − With this strategy, a series of GA-glycosides were synthesized utilizing methyl glycyrrhetinate and different glycosyl moieties by chemical methods to improve the pharmaceutical and biological activities of hydrophobic aglycone GA. , …”

“…However, this chemical glycosylation of natural products often requires rigorous reaction conditions, such as special temperature, catalyst, and multiple steps of protection/deprotection to control regioselectivity leading to the poor yield of the final glycosylated product. − Alternatively, glycosyltransferase offers a potential solution to this problem via transferring the glycosyl moiety from the sugar donor to the corresponding position of acceptor substrate in mild reaction conditions. , Nowadays, more and more glycosyltransferases have been found or engineered as biocatalysts to produce high value compounds in fine chemistry. − It was reported that the novel isobavachalcone glucosides with antiproliferative activities were synthesized by UDP-glycosyltransferase (YjiC) from Bacillus licheniformis DSM-13 . Currently, several glycosyltransferases have been reported for synthesizing triterpenoid saponins.…”

Saponins from European Licorice Roots (Glycyrrhiza glabra)

“…Furthermore, the NMR data of compounds 12, 15, and 20 could be complemented. 22,37,38,43,44 Mass spectrometric and NMR spectroscopic data (Tables S1− S11) of several previously identified saponins corresponded well with published data: glycyrrhizin (11), 45 LS-B2 (11deoxoglycyrrhizin, 12), 22,37,38 LS-G2 (24-hydroxyglycyrrhizin, 13), 38,44 LS-J2 (11-deoxo-24-hydroxyglycyrrhizin, 14), 33 glucoglycyrrhizin (15), 43 araboglycyrrhizin (16), 32,38 apioglycyrrhizin (17), 32,38 glycyrrhetinic acid-monoglucuronide (18), 46,47 LS-H2 (20α-glycyrrhizin, 19), 38,44 24-hydroxy-20αglycyrrhizin (20), 38,44 and LS-C2 (11-deoxo-11,13-glycyrrhizin diene, 21). 22,37,38 A comparison of selected key NMR data, shown in Figure 2, were used to support the structure elucidation of unknown saponins and might be useful in the future to determine new saponins.…”

“…H and13 C NMR data, see Table1; ESIMS m/z 977 [M + Na] + ; ESIMS/MS (DP 20 V, CE 50 V) m/z 977 (100), 655(33), 521(47), 439(10), 345(12), 261(5), 191 (6); HRESIMS m/z 953.4777 [M − H] − (calcd for C 48 H 73 O 19 , 953.4746). HRESIMS m/z 953.4781 [M − H] − (calcd for C 48 H 73 O 19 , 953.4746).…”