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Abstract
The thesis includes three parts, Part I, concerns the investigation of the leaves of the plant Pyrus Communis L. led to isolation a lot of volatile oils, hydrocarbons, methyl esters of fatty acids and ?-sitosterol. In addition to these compounds, some pentacyclic triterpenoids methyl ursolate (11b), ?-amyrin (2a), 3?-19?-dihydroxy-urs-?12-ene (106) and 3?-hydroxy-urs-?12(13),18(19)-diene (108) were also isolated and identified. Lanost-9(11)-en-3-ol (107) and 3?-hydroxy-urs-?12(13),18(19)-diene (108) have not been reported as constituents of leaves of Pyrus Communis L. Also, the triterpene compound which named as 3?-19?-dihydroxy-urs-?12-ene (106) was considered as a useful chemotaxonomic marker from the leaves of Pyrus Communis L.
Part II, deals with chemical study of Achillea Fragrantissima F., which belongs to the family compositae and grows in the desert of Egypt. Traditional medicine of Achillea reports that the plant has been used as analgesic, antihistaminic and anti-inflammatorable agent. Volatile oils and hydrocarbons of this plant were isolated and identified. Also, a mixture of capric, tridecanoic, myristic, pentadecanoic, palmitic, stearic acid methyl ester were isolated. Identification of sugar contents led to the presence of glucose, galactose and fructose. ?-sitosterol (1) was identified as the major sterol, ?-amyrin (2a) and ursolic acid (11a) as the major triterpenes of this plant. In addition to these known compounds, it afforded a new pentacyclic triterpene, methyl 2?-hydroxy-3-keto-urs-?12-en-28-oate (110). The structures of these compounds were elucidated by UV, IR, 1H-NMR, 13C-NMR, MS and GC/MS and comparison with authentic sample. Also, volatile oil from Achillea Fragrantissima F. exerted a bactericidic effect on several gram positive and gram negative bacterial strains due to the presence of ?-terpeneol and terpenyl acetate which posses antimicrobial activity.
Part III, involves a synthetic study on some isoprenoid compounds, ?-amyrin (2a), 3?,19?-dihydroxy-urs-?12-ene (106), ?-sitosterol (1) and cholesterol (4) as available and suitable substances of the extracted isoprenoid compounds from the studied plants, consequently, oxidation of such compounds was performed by using a mixture of chromium trioxide and dry pyridine to afford the corresponding 3-keto derivatives. Successive condensation of both the produced 3-keto compounds with the selected amino compounds, glycine, alanine, serine and o-aminobenzoic acid was described. The results gave an evidence to the formation of an additional ring in the reactions deal with o-aminobenzoic acid, which represented as anti Gram (+ve) and anti Gram (-ve) agents, then these may be used as abroad spectrum antibiotic.