In vitro antimicrobial activity of Sudanese medicinal plants

The development of drug resistance as well as appearance of undesirable side effects of certain antibiotics has lead to the search for new antimicrobial agents mainly from plant extracts with the goal to discover new chemical structures. To overcome these disadvantages, the research was carried out to investigate the in-vitro antibacterial and antifungal activity of Cadaba farinose (Capparaceae), Solanum nigrum (Solanaceae), Senna occidentalis (Caesalpiniaceae) and Maerua oblongifolia (Capparaceae). Eighty percent Methanol and chloroform extracts of leaves of plants were screened for their antimicrobial activity against different pathogenic bacteria and fungi. These were Staphylococcus aureus, Bacillus subtilus, Escherichia coli, Salmonella typhi and Aspergillus niger and Candida albicans using the cup plate agar diffusion method. All methanol extracts exhibited inhibitory effects against all tested organisms with zones of inhibition ranging from 11-25 mm except the methanol extract of both parts of Maerua oblongifolia were active against Escherichia coli and Aspergillus niger. The results obtained from plants extracts were compared to some of the commercially used drugs. The Minimum Inhibitory Concentrations (MICs) of the most active extracts of these plants against standard bacteria and fungi were also determined and found that MI Cs a ranging between concentration 2.5-5 mg mL-¹. All of the plants extracts were phytochemically screened and triterpenes, saponins and tannins were present in all of the methanolic extracts. Coumarins, sterols and triterpenes were found in all choloroform extracts, this finding indicated that these extracts of such plants promising antimicrobial agents.