The aim of the study was to investigating the phytochemical and combined antimicrobial sensitivity pattern of Chromolaena odorata and Acalypha wilkesiaana leaf extracts on selected bacterial organisms (S. aureus, E. coli and P. aeruginosa) using in vitro disc diffusion method. The extracts of both plants were tested on the selected organisms at three different concentrations, (20mg/ml, 30mg/ml and 50mg/ml). Zone of inhibition is presented as the mean ±Standard Deviation. Preliminary phytochemical test of Chromolaena odorata leaves indicates that carbohydrate, flavonoid, cyanogenic glycoside, phenolic constituent, fixed oil, anthraquinone and tripernoid/steroids were present, whereas Acalypha wilkesiana phytochemistry revealed the presence of carbohydrate, flavonoid, cyanogenic glycoside, phenolic constituent, anthraquinone and terpernoid/steroid. The combined action of both plants on the isolate showed a remarkable response to the test extracts in concentration dependent manner. S. auerus responded with inhibition zone of 2.0±1.0mm at 20mg/ml to 6.2±0.84mm at 50mg/ml, 2.0±0.710mm at 20mg/ml to 8.0±1.0mm at 50mg/ml for E. coli and 2.8±0.84mm at 20mg/ml to 7.5±0.05mm at 50mg/ml for P. aerugionosa. This study suggest that a combination of C. odorata and A. wilkesiana leaf extract elicit synergistic action on the test organisms, which could be attributed to the interaction between actions actions of various phyto nutrients identified during phytochemical analysis in the extracts of C. odorata and A. wilkesiana when combined compared to the action of each plant alone.

Antimicrobial sensitivity; Chromoleana odorata; Acalypha wilkesiana; Leaves extract; Phytochemical screening.

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