الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Literature survey revealed that genus Astragalus has great reputation for its immunostimulant, anticancer, antiviral and hepatoprotective properties. These activities are attributed to the presence of biologically active secondary metabolites including cycloartane saponins, oleanane saponins, polysaccharides, polyphenols, aliphatic nitrocompounds and alkaloids. These findings prompted us to carry out phytochemical investigation of two Astragalus plants namely, Astragalus kahiricus DC. and Astragalus spinosus Forssk.This thesis consists of three parts:
Part I: Phytochemical investigation of the roots of Astragalus kahiricus DC.
Part II: Quantitative determination of Astragaloside I and Astrasieversianin II in the alcoholic extracts of the roots of Astragalus spinosus Forssk. and Astragalus kahiricus DC. respectively by validated High Performance Liquid Chromatography (HPLC).
Part III: Antimicrobial, antiprotozoal and cytotoxic activities of some of the isolated saponins.
Part I
Phytochemical investigation of the roots of Astragalus kahiricus DC.
Nine compounds were isolated from the different extracts of the roots of Astragalus kahiricus DC. Five cycloartane saponins (AK1, AK3, AK4, AK5 and AK6) and one isoflavan AK2 were isolated from the chloroform extract. Two cycloartane saponins AK7 and AK8 were also isolated from the ethyl acetate extract. One sterol S1 was isolated from the petroleum ether extract.
The identification, characterization and structural elucidation of the isolated compounds were based on their chemical and spectral characters and comparison with authentic samples whenever possible.
Compound S1:
White crystals, m.p. 140˚, it was identified as β-sitosterol by comparison with an authentic sample.
Compound AK1:
Colourless crystals, m.p. 236-237◦, it was identified Astrasieversianin II.
Compound AK2:
Yellow flakes, m.p. 135-136˚, it was identified as 8-methoxy vestitol.
Compound AK3:
Colourless needles, m.p. 241-243◦C, it was identified as Cycloastragenol.
Compound AK4:
White needles, m.p. 190-192◦C, it was identified as Cycloastragenol-3-O-β –(2`, 3`-di-O-acetyl-4`-O-2-butenoyl) D-xylopyranosyl-6-O-β-D-xylopyranoside.