Antimicrobial Activity of Some Selected Medicinal Plants in Some Northern Parts of Bauchi State, Nigeria

Despite the influence of modern drugs the use of medicinal plants has remained a very important aspect of health care delivery system especially in rural areas. It was reported that 80% of world’s population relies on traditional medicines as primary source of their medication (Newman, 2006). The plant based preparations were central to traditional practice of health care system where herbs and different parts of medicinal plants are employed. Medicinal plants have some medicinal values based on folkloric usage and information. It was reported that plants are natural reservoir of therapeutic agents use by the local communities in the treatment of many diseases (Akinniyi and Tella, 1991). The clinical success of plant-based drugs has rekindled interest in research into medicinal plants as potential sources of new drugs. In some countries like China, India and Vietnam the research in to Abstract: Antimicrobial activity of some medicinal plants traditionally used by local communities in the treatment of tuberculosis and other respiratory diseases was carried out. The antimicrobial activity of the plants extracts against some microbial pathogens was investigated as preliminary study to screen the plants for their anti-tuberculosis activity. The antimicrobial test was done using agar disc diffusion method and the minimum inhibitory concentration (MIC) was also determined by Micro broth dilution method. The result indicated that the extracts had varied activity against the tested organisms. The extracts also showed dose dependent antimicrobial activity but significantly lower than the standard antibiotic drugs (ciprofloxacin and Ketoconazole). The extract of E. hirta has no activity against E. coli at the tested concentrations but shown the zone of inhibition range from 1016mm for other tested organisms. E. hirta has MIC of 15μg/ml against K. pneumonia and C.albicans and 30mg/ml for B.subtilis, S. typhi and S aureus. The extract of C. mucronata has shown zone of inhibition range from 1216mm but it has no activity against B. subtilis at the tested concentrations. It has MIC of 15μg/ml against C.albicans, B. subtilis, K.pneumonia, E.coli and 30μg/ml against S. aureus. The stem bark extract of X. americana has shown the zone of inhibition range of 10-16mm and active against all the tested organisms. It has MIC of 15μg/ml against S. aureus and K. pneumonia. The leaf extract of W. indica has shown zone of inhibition ranging from 1116mm. It was active against all the tested pathogens and exhibited MIC of 15μg/ml against S. aureus and C. albicans. The leaf extract of P. reticulatum has shown the zone of inhibition ranges from 9-15mm against the tested organisms. It exhibited MIC of 15μg/ml against S. typhi. The aerial parts extract of S. hermonthica has shown zone of inhibition ranges from 1216mm. The extract has shown the zone of inhibition (12, 14 and 16mm) against C. albicans at the concentration of 15, 30 and 60 μg/ml respectively. But the extract has no activity against S. typhi at the tested concentrations. The extract has MIC of 15μg/ml against B. subtilis and C. albicans. The extract of T. indica has shown the zone of inhibition ranges from 10-15mm. But the extract has no activity against C. albicans at all tested concentrations. It has MIC of 15μg/ml against K. pneumonia and E.coli. The extract of E. senegalensis has shown the zone of inhibition ranging from 1114mm. However the extract has no activity at the lowest concentration of 15μg/ml against all the organisms except S. aureus. The extract has MIC of 15μg/ml against S. aureus and 30μg/ml against all other organisms tested. The leaf extract of B. paradoxum has shown a zone of inhibition of 16mm against E. coli and zone of inhibition ranges from 1116mm. The MIC of the extract against E. coli, S. typhi and B. subtilis is 15μg/ml and 30μg/ml for C. albicans. However the extract has no activity at all tested concentrations against S. aureus and k. pneumonia. The extracts that exhibited zones of inhibition greater than 10mm were considered active and therefore recommended for further screening to isolate and characterize the bioactive chemical constituents.