This study was carried out to determine the combinatorial antibacterial activity of the crude extracts of leaves of Thaumatococcus daniellii and Calotropis procera against selected clinical isolates. The leaves of the plants were plucked and washed separately and air dried at 28 ^oC for two weeks, samples were then pulverized to powdered form. The clinical isolates used against the plants extracts were Escherichia coli and Pseudomonas aeruginosa. The solvents used were acetone and distilled water and the plant samples were extracted using standard methods. Qualitative phytochemical screening was determined using standard procedures. Antibacterial activity of the plants extracts was carried out using agar well diffusion method. Minimum Inhibitory and Bactericidal Concentrations were carried out using standard procedure. Combinatorial antibacterial activity of the plants extracts was obtained using standard method. Qualitative phytochemical screening of the plant extracts revealed the presence of flavonoids, phenols, glycosides, saponin and tannins in both C. procera and T. daniellii. Acetone and aqueous extracts of T. daniellii had antibacterial activity against E. coli with a zone of inhibition of 34.05±0.25 mm and 31.00±1.00 mm at 200 mg/ml respectively. Acetone and aqueous extracts of C. procera had antibacterial activity against P. aeruginosa with zone of inhibition of 32.30±0.30 mm and 34.50±0.50 mm at 200 mg/ml respectively. Combined Acetone and aqueous plants extracts against E. coli  was 34.40±0.20 mm and 35.70±0.30 mm zones of inhibition respectively at 200 mg/ml. The MIC and MBC of the plant extracts against the clinical isolates ranged from 120 mg/ml - 180 mg/ml. The MIC and MBC of combinatorial activity of acetone and aqueous leaves extracts of C. procera and T. daniellii ranged from 180 mg/ml- 200 mg/ml. The findings from this study justify the antibacterial efficacy of the combinatorial leaves extracts of C. procera and T. danielli against P. aeruginosa and E. coli.

Keywords:  Thaumatococcus daniellii, Calotropis procera, Antibacterial, Phytochemicals, Combinatorial, Agar well