- Chemical transformation of ginsenoside Re by a heteropoly acid investigated using HPLC-MS: N/HRMS
-
The potential of heteropoly acid H3PW12O40 to catalyze the chemical transformation of ginsenoside Re into rare ginsenosides was explored. This homogeneous catalyst can be recycled by extraction with diethyl ether. Eight resulting products were separated and identified through a developed high-performance liquid chromatography coupled with multistage tandem mass spectrometry and high-resolution mass spectrometry (HPLC-MSn/HRMS) method. Multistage tandem mass spectrometry was employed to trace the source of fragments and determine fragmentation pathways. Also, high-resolution mass spectrometry was used for the accurate structural elucidation of fragments. Ginsenosides 25-OH-Rg6 and 25-OH-F4, consisting of the aglycone structures of 3β, 12β, 25-trihydroxy-dammar-20 (21/22)-ene , were obtained via chemical transformation for the first time. Chemical transformation pathways of ginsenoside Re were summarized, which involved deglycosylation, hydration, dehydration, and epimerization reactions. A carbenium ion mechanism was further employed to elucidate each transformation process, and the stability of carbenium ions was supposed to be responsible for the reaction pathways and selectivity.
- Xiu, Yang,Zhao, Huanxi,Gao, Yue,Liu, Wenlong,Liu, Shuying
-
-
Read Online
- Biotransformation of Ginsenosides Re and Rg1 into Rg2 and Rh1 by Thermostable β-Glucosidase from Thermotoga thermarum
-
The recombinant thermostable β-glucosidase from Thermotoga thermarum DSM 5069T exhibited high selectivity to catalyze the conversion of ginsenoside Re and Rg1 to the more pharmacologically active minor ginsenoside Rg2 and Rh1, respectively. At a concentration of 1.36 U/mL of the enzyme, a temperature of 85°C, and pH 5.5, 10 g/L ginsenoside Re was transformed into 8.02 g/L Rg2 within 60 min, and 2 g/L ginsenoside Rg1 was transformed into 1.56 g/L Rh1 within 60 min. This paper provides the first report on the production of ginsenoside Rg2 and Rh1 by a highly thermostable β-glucosidase.
- Pei, Jianjun,Wu, Tao,Yao, Tao,Zhao, Linguo,Ding, Gang,Wang, Zhenzhong,Xiao, Wei
-
-
Read Online
- Microbial transformation of 20(S)-protopanaxatriol-type saponins by Absidia coerulea
-
Three 20(S)-protopanaxatriol-type saponins, ginsenoside-Rg1 (1), notoginsenoside-R1 (2), and ginsenoside-Re (3), were transformed by the fungus Absidia coerulea (AS 3.3389). Compound 1 was converted into five metabolites, ginsenoside-Rh4 (4), 3β,2β,25- trihydroxydammar-(E)-20(22)-ene-6-O-β-D-glucopyranoside (5), 20(S)-ginsenoside-Rh1 (6), 20(R)-ginsenoside-Rh1 (7), and a mixture of 25-hydroxy-20(S)-ginsenoside-Rh1 and its C-20(R) epimer (8). Compound 2 was converted into 10 metabolites, 20(S)-notoginsenoside-R 2 (9), 20(R)-notoginsenoside-R2 (10), 3β,12β,25- trihydroxydammar-(E)-20(22)-ene-6-O-β-D-xylopyranosyl-(1→2) -β-D-glucopyranoside (11), 3β,12β-dihydroxydammar-(E)-20(22),24- diene-6-O-β-D-xylopyranosyl-(1→2)-β-D-glucopyranoside (12), 3β,12β,20,25-tetrahydroxydammaran-6-O-β-D-xylopyranosyl- (1→2)-β-D-glucopyranoside (13), and compounds 4-8. Compound 3 was metabolized to 20(S)-ginsenoside-Rg2 (14), 20(R)-ginsenoside-Rg 2 (15), 3β,12β,25-trihydroxydammar-(E)-20(22)-ene-6-O- α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (16), 3β,12β-dihydroxydammar-(E)-20(22),24-diene-6-O-α-L- rhamnopyranosyl-(1→2)-β-D-glucopyranoside (17), 3β,12β,20, 25-tetrahydroxydammaran-6-O-α-L-rhamnopyranosyl-(1→2) -β-D-glucopyranoside (18), and compounds 4-8. The structures of five new metabolites, 10-13 and 16, were established by spectroscopic methods.
- Chen, Guangtong,Yang, Min,Lu, Zhiqiang,Zhang, Jinqiang,Huang, Huilian,Liang, Yan,Guan, Shuhong,Song, Yan,Wu, Lijun,Guo, De-An
-
p. 1203 - 1206
(2008/02/13)
-
