الفهرس 
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Abstract
Ricinus communis L.(Castor oil plant) is a widely distributed fast-growing plant with great economic and environmental value. The economic importance of R.communis is attributed to the production of castor oil from its seeds to be used in various industries.In addition to castor oil,the poisonous seeds of R.communis contain the extremely toxic protein (ricin),other toxic allergens and the alkaloid ricinine.In spite of being an environmental hazard, the toxic residue (castor meal) left after extraction of the castor oil from castor seeds represents a rich source for ricinine alkaloid
Part I: Isolation and derivatization of ricinine:The alkaloid ricinine was isolated from R. communis seeds in a high yield using a simple method.It was used as a starting compound for the synthesis of twenty-three ricinine derivatives;eighteen new (5-9 & 12-24) and five known (2-4, 10 & 11) derivatives.Part II: Biological evaluation of ricinine and its derivatives: Bioavailability and pharmacokinetics as well as toxicity are very important areas in drug discovery.Therefore,molecular properties,ADMET,and drug-likeness of ricinine and its prepared derivatives were investigated using in-silico studies. These studies showed that all the tested compounds exhibited highly predicted gastrointestinal absorption. Most of them showed no toxicity or reproductive effects. The cytotoxicity study of ricinine and its derivatives against oral squamous cell carcinoma (OSCC) showed that compound 19 had the highest cytotoxic activity among all tested compounds (69 % inhibition). Docking study of ricinine and its derivatives against Akt1 protein showed that compounds 18 and 19 showed the highest binding affinity to Akt1.The most active cytotoxic compound (19) showed specific inhibition of Akt1 at 50 M concentration and it did not affect other Akt isoforms.Unexpectedly,Compound 18 did not show inhibition of Akt isoforms,and it showed paradoxical Akt overexpression.The antimicrobial and antiquorum-sensing study of ricinine (1),some of its derivatives (3, 4, 10, 11, 23,and 24),total MeOH extracts of leaves and seeds of R.communis,EtOAc and aqueous fractions of the seed extract and castor oil indicated that 4 showed the highest antimicrobial activity and 10 showed the highest antiquorum-sensing activity among the tested ricinine derivatives and R.communis extracts.It was also found that although ricinine does not contribute to the antimicrobial activity of the leaf and seed extracts of R.communis plant,it represents a good scaffold for antimicrobial and antiquorum-sensing derivatives.