Aya M. Asaad

Cycloartane triterpene glycosides from Astragalus trigonus

Three new cycloartane glycosides, trigonoside I, II and III, and the known astragalosides I and II were isolated from the roots of Astragalus trigonus. The structures of the new glycosides were totally elucidated by high field (600 MHz) NMR analyses as cycloastragenol-6-O-beta-xylopyranoside, cycloastragenol-3-O-[alpha-L-arabinopyranosyl(1-->2)-beta-D- xylopyranosyl]- 6-O-beta-D-xylopyranoside and cycloastragenol-3-O-[alpha-L-arabinopyranosyl (1-->2)-beta-D-(3-O-acetyl)-xylopyranosyl]-6-O-beta-D-xylopyranoside.

Cycloartane triterpene glycosides from Astragalus alexandrinus

Abstract Alexandroside I, a new cycloartane triterpene glycoside was isolated from Astragalus alexandrinus. Its structure was established as 3-O-β- d -glucopyranosyl-9β,19-cyclolanost-3β,6α,16β,24(R),25 pentaol on the basis of spectroscopic and chemical methods. Four known glycosides, astraversianins VI, X, XIV and XV, were also isolated.

Cycloartane triterpene glycosides from Egyptian Astragalus species.

Abstract Tomentoside I, a new tetranor-cycloartane triterpene glycoside was isolated fromAstragalus tomentosus. Its structure was established as 6α-acetoxy-23-ethoxy-16β,23(R)-epoxy-24,25,26,27-tetranor-9,19-cyclolanosta-3β-O-xyloside, on the basis of spectral evidence. 3-O-Methyl-chiro-inositol ether was also isolated and identified. The known compound, astragaloside II, previously isolated fromA. spinosus, was also identified.

Chemical constituents from Astragalus annularis Forssk. and A. trimestris L., Fabaceae

The phytochemical investigation of the aerial parts of Astragalus annularis Forssk. and A. trimestris L., Fabaceae, growing in Egypt, resulted in the isolation of eight compounds, for the first time from these two species. These compounds were identified by chemical methods, NMR spectroscopy, UV spectroscopy as well as MS analysis. The antimicrobial activity of the isolated compounds were tested against Staphylococcus aureus, Esherichia coli and Candida albicans.

Hepatoprotective effects of Astragalus kahiricus root extract against ethanol-induced liver apoptosis in rats

The hepatoprotective activity of the ethanol extract of Astragalus kahiricus (Fabaceae) roots against ethanol-induced liver apoptosis was evaluated and it showed very promising hepatoprotective actions through different mechanisms. The extract counteracted the ethanol-induced liver enzymes leakage and glutathione depletion. In addition, it demonstrated anti-apoptotic effects against caspase-3 activation and DNA fragmentation that were confirmed by liver histopathological examination. Moreover, the phytochemical study of this extract led to the isolation of four cycloartane-type triterpenes identified as astrasieversianin II (1), astramembrannin II (2), astrasieversianin XIV (3), and cycloastragenol (4). The structures of these isolates were established by HRESI-MS and 1D and 2D NMR experiments. The antimicrobial, antimalarial, and cytotoxic activities of the isolates were further evaluated, but none of them showed any activity.

Densitometric kinetic stability studies of some plant extracts using different regression methods

Literature review revealed that no published work described a quantitative method to determine the expiry dates of natural plant raw materials. In this work, a high-performance thin-layer chromatography (HPTLC) analytical work was performed to follow up the stability of some selected medicinal plants, namely, peppermint, basil, rosemary, eucalyptus, marjoram, lemon grass, and olive leaves; anise, caraway, and coriander fruits; cardamom seeds; and cinnamon barks. Some changes, whether being major or minor, over storage were observed for all the tested plants under the applied stability-testing conditions, which in turn triggered us to adopt a quantitative approach with the aim of investigating whether those changes would reflect an alarm of expiry of the examined plants or not.