ABSTRACT

This study was to determine the antimicrobial activities of the extracts of Phyllantus amarus and Andrographis paniculataon some human pathogens. The practice of using plants and plant extract to manage, control or cure diseases is as old as mankind. Different plant parts are used in this regard, including roots, stems, leaves, flowers, fruits, twigs and exudates, and have been used for extraction of raw drugs (Ankita, 2012). The test plants, Andrographis paniculata and Phyllantus amarus, were sourced from homestead farms within NRCRI Staff quarters. The test organisms, Escherichia coli and Staphylococcus aureus and Candida albicans, were obtained from the Vertinary Research Institute, Laboratory Sub-station, Umudike. The present study revealed that there are significant variations in the quantity of the various phytochemicals in the two plants. From the result, it was found that most phytochemicals were higher in A. paniculata than in the P. amarus. Also, the levels of cyanide (HCN) in both plants was found to be relatively low at 7.08mg/kg for the A. paniculata and P. amarus leaves. The antimicrobial activities of the plant extract revealed that the three extracts of A. paniculata(water, ethanol and acetone) displayed varying levels of activity against Escherichia coli with inhibition diameters in the range of 12.0mm (acetone) to 17.67mm (ethanol). In comparison, extracts of A. paniculata were more potent than those of P. amarus generally. The minimum inhibitory concentration revealed that ethanol and acetone soluble plant extracts of A. paniculata were active against all the test isolates but ethanol extract of A. paniculata demonstrated greater antimicrobial activity on Staphylococcus aureus, Escherichia coli, and Candida albicans at the range of l 2.5mg/ml each while the minimum bactericidal concentration showed that ethanol soluble extracts of A. paniculata showed greater activity against Staphylococcus aureus, and Candida albicans at 100mg/ml, when compared to the acetone plant extract. It is therefore, suggestive that the findings in this work appear to justify the use of both plants in many traditional and ethnic medications.