In-Vitro Antimicrobial Activities and Phytochemical Screening of Calotropis Procera (Ait) and Vernonia Amygdalina (Del.) Extracts Against Some Medically Important Pathogenic Bacteria

Abstract

The aim of this study is to evaluate phytochemical screening and antibacterial activities of crude extracts obtained from different parts of Calotropis procera and Vernonia amygdalina against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The stems, roots and leaves of the selected plant species were shade dried and ground to powders and the bioactive components were extracted using ethanol (99.5%), methanol (99.8%), hexane (99.8%) and distilled water. The antibacterial activities of the resulting extracts against the three selected pathogens were evaluated using paper disc method and inhibitory zones were recorded in millimeters at five different concentrations (20, 30, 40, 50 and 60 mg/ml). Agar dilution method is used to determine minimum inhibitory concentrations (MICs) of the plant extracts against selected pathogens. Chloramphenicol and DMSO used as positive and negative controls, respectively. The bioassay results revealed that the crude extracts of ethanol, methanol, hexane and water had antibacterial activities on all three bacterial species at all concentration except at 20 mg/ml of all solvent extracts. Methanol and ethanol extracts had the highest growth inhibitory effects as compared with those of the aqueous and hexane crude extracts. However, the four solvent crude extracts had less antibacterial activities than chloramphenicol. S. aureus found to be the most susceptible pathogen to the crude ethanol (99.5%) and methanol (99.8) extracts of the leaves of Vernonia amygdalina (22 mg/ml) and ethanol extract of the leaves of Calotropis procera (22 mg/ml). Whereas Pseudomonas auruginosa was the least susceptible bacterium to crude ethanol extract (99.5%) of the root of Calotropis procera at 28 mg/ml and crude water, extract of the root of Vernonia amygdalina at 28 mg/ml. The growth inhibitory activities of the crude extracts were found to be significantly different for the four concentrations (30, 40, 50 and 60mg/ml) in both plant parts (p < 0.05). Phytochemical screening were done and the following bioactive components are detected such as Tannins, Phenolics, Resins, Amino acids, Flavonoids, Saponins, Reducing sugar, Glycosides, Steroids, Triterpenoids, Anthocyanidins, Sterol and Volatile Oil. In conclusion, this study did not only show the antibacterial activities of Calotropis procera and Vernonia amygdalina, but also offered a scientific validation for its traditional use against some diseases. There is a need for conducting more studies to identify and characterize the medicinal properties in the tested plant, which may serve as novel compounds for the development of new and more effective antimicrobial drugs.