Triterpene Glycosides from the Roots of Astragalus flavescens

Abstract

Six new triterpene saponins, 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (1), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (2), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (3), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (4), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-alpha-L-arabinopyranosyl-21-epi-kudzusapogenol A (5), and 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-alpha-L-arabinopyranosyl-21-epi-kudzusapogenol A (6), were isolated from the roots of Astragalus flavescens, together with the known trajanoside B, azukisaponin V, and astragalosides IV, VII, and VIII. Their structures were established mainly by 2D NMR techniques and mass spectrometry.

Glycosides from Breynia fruticosa and Breynia rostrata

“…Unambiguous assignments of proton and carbon resonances in the NMR spectra were based on extensive analysis of HSQC, 1 H-1 H COSY and TOC-SY spectra of 8. The two anomeric carbon signals at d C 103.4 and 102.6 in combination with the chemical shifts and coupling patterns of the two anomeric protons [4.18 (d, J = 6.7 Hz) and 4.63 (d, J = 6.9 Hz)] and other characteristic NMR resonances, suggested that the two sugar moieties were b-xylopyranosyl and bglucopyranosyl, respectively (Agrawal, 1992;Avunduk et al, 2008). The sugar sequence and their linkage sites were derived from the 13 C-1 H long-range correlation signals at H-1 glc (d H 4.63)/C-5 (d C 152.2); H-1 xyl (d H 4.18)/C-6 glc (d C 68.3), and H-6 glc (d H 3.52, 3.94)/C-1 xyl (d C 103.4) in its HMBC spectrum.…”

Antigenotoxic properties of two newly synthesized β‐aminoketones against N‐methyl‐N′‐nitro‐N‐nitrosoguanidine and 9‐aminoacridine‐induced mutagenesis

“…The synthesis and determination of biological activities of various compounds are very important strategies owing to their large‐scale usefulness in industrial and medicinal areas 10,28,29. In this regard, synthetic β‐aminoketones, which is a Mannich base derivative formed in the reaction of an amine, formaldehyde (or an aldehyde), and a carbon acid, have a great potential to be candidates for industrial and medicinal applications.…”

Spirostane and cholestane glycosides from the bulbs of Allium nigrum L

“…In the 1 H NMR spectra of the compounds, the relatively large 3 J H-1,H-2 values of the glucose, xylose, and galactose (between 7.0 and 8.0 Hz) moieties indicated a b anomeric proton. The broad singlet of the anomeric proton of the rhamnose unit indicated an a-orientation (Avunduk et al, 2008).…”