In this dissertation, Monotheca buxifolia and Bosea amherstiana were assessed for isolation and structural elucidation of their compounds. The phytochemical investigations of Monotheca buxifolia includes lauric acid (1), oleanolic acid (2) and bis (2-ethylhexyl) phthalate (3) while Bosea amherstiana incudes quercetin (4), gallic acid (5) and cinnamic acid (6). The pharmacological and biological activities of crude extract, different fractions thereof, and some compounds isolated in reasonable quantity from Monotheca buxifolia and Bosea amherstiana were investigated. The plants exhibited moisture, fat, fiber, nitrogen, and protein contents. Biological investigation shows significant antibacterial and phytotoxic activity exhibited by the secondary metabolites of Monotheca buxifolia and Bosea amherstiana against L. minor plants and cytotoxicity activity in brine shrimps. Moreover, Monotheca buxifolia and Bosea amherstiana showed moderate inhibition against urease and carbonic anhydrase. The potency of Monotheca buxifolia and Bosea amherstiana for inhibiting the growth of laryngeal cancer cells was determined by MTT assay at concentrations of 200 μg/ml and 150 μg/ml. The IC50 values of Monotheca buxifolia ranged from 80.6214 ± 1.89 μg/ml to 244.506 ± 2.43 μg/ml, while the IC50 values of Bosea amherstiana ranged from 108.564 ± 1.28 μg/ml to 206.053 ± 1.54 μg/ml. A comet assay was performed for the determination of DNA damage and the protective activity of the plant extracts against H2O2-induced human lymphocytes. The maximum protective effect of lymphocyte pretreatment was observed with the dichloromethane fraction of Monotheca buxifolia, which was 5.21 ± 0.030% tail DNA, while the Olive tail moment was 0.61 ± 0.03 compared with the rest of the treated Monotheca buxifolia samples. In Bosea amherstiana, the methanolic fraction had more protective effects against H2O2-induced lymphocytes, with 6.36 ± 2.23% tail DNA and an Olive tail moment of 0.84 ± 0.40. Antioxidant enzymes of lymphocytes were assessed. MB has an effective role in decreasing lipid peroxidase (TBAR) enzymes. The methanol, dichloromethane, and ethyl acetate fractions of MB were more effective (2.3, 2.4, and 2.7, respectively), while the aqueous fraction of MB increased the LPO slightly to 8.1. Both MB and MA had slight effects on the catalase (CAT) enzymes. The dichloromethane fraction of Bosea amherstiana increased the CAT enzymes slightly, while the aqueous fraction of Monotheca buxifolia lowered the concentration of CAT enzymes compared with the control. The dichloromethane fraction of MB slightly increased the peroxidase (POD) enzymes’ value to 31.2, while the aqueous extract of MB lowered the POD enzymes to 20.51. MB had no effect on decreasing or increasing superoxide dismutase (SOD), while BA contributed to lowering the SOD values. In terms of acute toxicity in vivo, both plants were found to be safe at all the test doses (500, 1,000, 1,500, and 2,000 mg/kg. Monotheca buxifolia and Bosea amherstiana (50, 100, and 150 mg/kg) dose dependently reduced abdominal constrictions in mice. Both plants exhibited significant (p < 0.0001) sedative effects at doses of 50, 150, and 150 mg/kg; however, they should be considered mild to moderate sedatives, as the sedation induced was for the less standard drug diazepam. Both plants markedly (p < 0.0001) reduced yeast-induced hyperthermia. CCl4 treatment considerably increased (p < 0.01) the activity of liver serum marker enzymes, such as liver LDH, serum LDH, ALP, AST, and ALT compared with the control group. The protective effect of Monotheca buxifolia was assessed by measuring the serum markers, assays of antioxidant enzymes, genotoxicity, and DNA damage. Monotheca buxifolia inverted the activities of the serum marker enzymes, and the cholesterol profile was damaged by CCl4 treatments. Activities of antioxidant enzymes of the liver tissue homogenates were assessed; CAT, SOD, and peroxidase (POD) were reduced with CCl4 administration, and they were retained with Monotheca buxifolia. The administration of Monotheca buxifolia and Bosea amherstiana reduced hepatic damage, with fewer or no fatty changes, expansion of blood vessels, or constant morphology of the hepatocytes in the control group. The isolated compounds of lauric acid, oleanolic acid, and bis(2-ethylhexyl) phthalate inhibited the growth of laryngeal cancer cells, as determined by MTT assay. The IC50 value for lauric acid was 56.4584 ± 1.20 μg/ml, that for oleanolic acid was 31.9421 ± 1.03 μg/ml, and that for bis(2-ethylhexyl) phthalate was 83.8019 ± 2.18 μg/ml. After 24 h of treatment, 29.5% of Hep G2 cells treated with lauric acid, 52.1% of those treated with oleanolic acid, and 22.4% of those treated with bis(2-ethylhexyl) phthalate were apoptotic.