Antimicrobials are harmful to microorganisms. Antimicrobials deal with inhibiting the survival and living of microorganisms. Drugs that negatively affect the growth of microorganisms are used to fight microorganisms, including bacteria and fungi. Phytochemical studies deal with identifying the chemicals inherent in a plant and their usefulness in contributing to the use of the plant for various purposes, including preventing the thriving of microorganisms. It also means selective toxicity that kills microorganisms without harming humans or animals. This study was conducted to investigate the antimicrobial activities based on the phytochemicals present in the stem bark extract of C. echinata. The phytochemical studies of the plant were conducted by the addition of various standard reagents. The plant structures were also elucidated by qualitative microscopy and microscopical examination of the transverse section of the stem. Antimicrobial studies were carried out on microorganisms using the agar well diffusion method. The microorganisms tested included Staphylococcus aureus and others, and the concentrations from which the growth inhibition of microorganisms was observed were 50 mg/ml for both Escherichia coli and Salmonella typhi, but 100 mg/ml was noted for the fungus Candida albicans, and upwards of 200 mg/ml. Much activity was not recorded for S. pyogenes and E. faecalis. The antimicrobial analysis also showed that the plant stem extract was highly active against Escherichia coli with an inhibitory zone diameter (IZD) of 26mm ±2.83 at 200mg/ml and a pod borer diameter of 08mm. From this, it can be inferred that the IZD is about three times the pod borer diameter, which shows high activity at 200 mg/ml. 100 mg/ml concentration had an IZD of 20mm, but there was no significant activity at 25 mg/ml because no clear zone was observed around the extract in the bore. However, this is quite different from that seen in the control (neomycin and fluconacole were used), which has inhibition at concentrations as low as 2.5 mg/ml and 5 mg/ml, showing IZD of 17±1.41mm and 33±2.83 mm, respectively. From this, it can be inferred that the extract is not potent enough against conventional antimicrobials. In the sensitivity test, the extract of 50 mg/ml concentration was sensitive to the organisms. Thus, the presence of the secondary metabolites present in the plant, such as alkaloids, saponin, glycosides, protein, and tannins, contributed to the antimicrobial activity of this plant extract against microorganisms.
Samuel Chibueze (Pharm. D) Udeh (Mon,) studied this question.