Phytochemical, Antioxidant and Antibacterial Activities of Vernonia amygdalina Del. Leaf Extract

Abstract

Scientific standardization as well as possible therapeutic effects of some herbal preparations, alternatives against antibiotic resistant bacterial infections indicates a strong need for conti- nuous effort to validate the use of plant materials as alternative therapy regimens with similar or higher antibiotic beneficial properties. The study was aimed to at evaluating the phytoche- mical, antioxidant, antibacterial activities of Vernonia amygdalina leaves. Phytochemical screeing was achieved using standard qualitative phytochemical screening procedures. Antibacterial studies were carried out using agar well diffusing methods. The antioxidant activities of the methanol extract was determined using of 2, 2-diphenyl-1picrylhydrazyl (DPPH) assay. Flavo- noid, alkaloids, tannins, saponins, steroids, triterpenes, carbohydrate and phenols were detec- ted in methanolic extract. The methanolic extract showed higher radical scavenging ability than ascorbic acid at the highest concentration of 1000 μg/mL. The IC₅₀ values of the methanol  extract of Vernonia amygdalina leaves against DPPH free radical were 20.625 μg/ml. The mini- mum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the Vernonia amygdalina leaf extract recorded respective values of 15.625 mg/ml and 31.25 mg/ml against Pseudomonas aeruginosa and Escherichia coli and 7.8125 mg/ml and 15.625 mg/ml against Staphylococcus aureus. The FTIR analysis showed the presence of alcohol, phenol, carboxylic acid, aldehyde and ketone functional group. This study has proven the effectiveness and efficacy of Vernonia amygdalina against the tested clinical isolates.