The work described in the present thesis is mainly concerned with the phytochemical investigations of Prunus armeniaca. The thesis begins with the introduction of the chemistry of natural product's background that provides the review of the earlier contributions made in the field of chemistry of the plant. A brief review of the biosynthesis of triterpenoids and steroids with particular reference to the pentacyclic triterpenoids, and flavonoids is also included.
The experimental section deals with the isolation and purification of the constituents present in the fruits and seeds of P. armeniaca. As a result of these investigations total twenty three compounds are reported. Among these, five are new, eleven isolated and reported first time from the (dry) fruits of this plant and the remaining seven compounds are known and reported previously. The compounds belonged to pentacyclic triterpenoids, steroids, flavonoids and their glycosides. These have been isolated from the non-polar, semi polar and polar fractions.
GC and GC-ElMS analysis of the petroleum ether extract of seeds also revealed the presence of different compounds. Upon characterization, among, seven were found to be reported first time while the remaining four were reported previously.
The polar fraction of the fruits mainly led to the isolation of flavonoids representing the flavonol, flavanonol, flavanone and flavone as basic structural units, flavonoid glycosides belonged to flavonol type nuclei glycosilated at 7 and 3 positions, respectively. The characterization and structure elucidation of the triterpenoids, flavonoids and their glycosides is described under the section "Results and discussion".
The structures of the new and known compounds have been elucidated through spectral studies including IR, UV, ElMS, HREIMS, ID 1H, 13C- NMR (Broad Band and DEPT) and 2D-NMR (COSY-45, NOESY, J-resolved, HMQC and HMBC) spectral analysis as well as chemical transformations.
The biological activities of the pure compounds and plant extracts were determined by the Department of Microbiology, university of Karachi. The antioxidant activity of different plant extracts was carried out in HEJ, Research Institute of Chemistry, university of Karachi.