Chemical Constituents of the Roots of Astragalus polycladus var. nigrescens

Abstract:

A new cycloartane triterpenoid, 24-acetylcyclocantogenin (1), along with five cycloartane triterpenoids (2-6), eight steroids (7-14) and nine other known compounds (15-23), was obtained from the methanol extract of roots of Astragalus polycladus var. nigrescens. Their structures were elucidated based on extensive spectroscopic analysis (1D and 2D-NMR, MS and IR). They were isolated from A. polycladus var. nigrescens for the first time.

Unusual secondary metabolites from Astragalus halicacabus LAM

From the whole plant of Astragalus halicacabus (Sect. Halicacabus), a new cycloartane-type glycoside, (20R,24S)-3-O-[α-L-arabinopyranosyl-(1→2)-β-D-xylopyranosyl]-20,24-epoxy-16-O-β-D-glucopyranosyl-3β,6α,16β,25-tetrahydroxycycloartane, and a new glycoside, 3-O-[β-D-apiofuranosyl-(1→2)-β-D-glucopyranosyl]maltol were isolated together with seven known cycloartane-type glycosides, i.e., cyclocanthoside D, askendosides D, F, and G, cyclosieversioside G, cyclostipuloside A, elongatoside, and a known maltol glucoside, 3-O-β-D-glucopyranosylmaltol. The structures were elucidated by means of high-resolution mass spectrometry, and extensive 1D- and 2D-NMR spectroscopic analysis. This is the first phytochemical work on A. halicacabus, and a maltol glycoside was encountered for the first time in the Leguminosae family.

Cycloartane glycosides from Astragalus stereocalyx Bornm

Six cycloartane-type triterpene glycosides were isolated from Astragalus stereocalyx along with six known cycloartane-type glycosides. Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis. Three compounds are based on an aglycon characterized by the occurrence of an unusual hydroxyl group at position 20, whereas three other compounds are based on cycloasgenin C as aglycon, so far reported from Astragalus spp. All the compounds were tested for their cytotoxic activity against a number of cancer cell lines. One compound exhibited activity versus human cervical cancer (Hela) with an IC(50) value = 10 μM.