Triterpene glycosides from Astragalus and their genins. XC. Askendoside K from Astragalus taschkendicus

Abstract

A new triterpene cycloartane glycoside called askendoside K was isolated from roots of Astragalus taschkendicus Bunge (Leguminosae). The structure of this glycoside was established using chemical and biochemical transformations and spectral data.In continuation of research on polar triterpene glycosides from Astragalus taschkendicus Bunge (Leguminosae) [1], we isolated one more new glycoside from roots of this plant and called it askendoside K (1). Herein we report the structure determination of this glycoside.The PMR spectrum of 1 (Table 1) exhibited at strong field 1H doublets for an AX system at G 0.06 and 0.35 that belonged to the isopropane methylene of a cyclopropane ring in addition to resonances for seven methyls. As expected, the 13 C NMR spectrum of this same glycoside showed resonances at G 21.12, 29.03, and 30.23 for quaternary C-9 and C-10 and methylene C-19 composing the three-membered ring, indicating that the studied glycoside was a cycloartane triterpenoid [2][3][4][5]. 1 2 -4, 6 5 OH OH OH OH O O HO OH OH O HO HO O OH OH O CH 2 OH OH O CH 3 OOC 2 -5 6 Enzyme Í + OH OH OH OH RO R 1 O OH OH OH OH O O HO O OH OH OH O O HO HO HO O OH OH O CH 2 OH OH O HOOC 2: R = R 1 = H; 3: R = E-D-Xylp, R 1 = H 4: R = H, R 1 = E-D-GlcUA(1o2)-E-D-Glcp 6: R = D-L-Arap(1o2)-E-D-Xylp, R 1 = E-D-Glcp

A Review of Recent Research Progress on the Astragalus Genus

“…As the summarized results shown in Table 1, Table 2 and Table 3 and Figure 1, Figure 2, Figure 3 and Figure 4, 46 kinds of Astragalus species have been studied for their chemical constituents in recent years [9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,…”

Five New Triterpenoid Saponins from the Rhizomes of Panacis majoris and Their Antiplatelet Aggregation Activity

“…It must be mentioned that the chemical shift of C-24 could be deemed to be a typical parameter in the determination of the configuration of C-24 [16]. In the case of the 24(S) configuration, the chemical shift for C-24 gives a resonance at δ C 77.0-78.2 [17][18][19], while for the 24(R) configuration, the chemical shift for C-24 gives a resonance at δ C 79.9-80.6 [20][21][22][23]. Hence, the configuration of C-24 (δ C 80.2) was determined to be R. According to the available data in the literature [24], the 20(S)-configuration was decided by the chemical shift of C-21 (δ C 27.5).…”

Triterpenoids

“…In separate studies ten new cycloartanes and glycosides 87-96 64 and three new glycosides, two (97 and 98) with new genins, 65 Novel cycloartane saponins with known genins include askendoside K from Astragalus taschkendicus, 75 cicerosides A and B from Astragalus cicer, 76 shengmaxinsides A-C from Cimicifuga simplex, 77 and unnamed saponins from Astragalus mucidus. 78 The biological activities of cycloartane triterpenoids have been reviewed.…”