Exploring Vernonia amygdalina’s leaf extracts for phytochemical screening and its anti-bacterial activities

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ABSTRACT The aim of this study was to screen the phytochemicals and assess the antibacterial properties of crude extracts from Vernonia amygdalina leaves against specific pathogenic bacteria. Qualitative and qauntitave analysis was performed on both ethanol and ethyl acetate crude extracts using standardized techniques. The analysis revealed the presence of alkaloids, phenol, flavonoids, terpenoids, saponins, tannins, and cardiac glycosides in the ethanol extract, while saponins and glycosides were absent in the ethyl acetate extract. The quantities of phenols, flavonoids, and alkaloids were determined using Gallic acid, quercetin, and atropine assays, respectively. The ethanol extract contained 154.7 ± 3.6 (mg GAE/g) of total phenols, 33.3 ± 1.8 (mg QE/g) of flavonoids, and 2.4 ± 0.08 (mg AE) of alkaloids, whereas the ethyl acetate extract contained 93.7 ± 3.9 (mg GAE/g) of total phenols, 30.7 ± 8.3 (mg QE/g) of flavonoids, and 1.57 ± 0.3 (mg GAE/g) of alkaloids. This study identified 44 components in the ethanol crude extract and 10 components in the ethyl acetate crude extract. The presence of alkanes, alkenes, amines, carboxylic acids, and alcohols was confirmed by FT-IR analysis. Each crude extract was tested at concentrations of 500 mg/mL, 250 mg/mL, 125 mg/mL, and 62.5 mg/mL using the same method. A concentration of 0.001 mg/mL of Penicillin capsule standard drugs and dimethyl sulfoxide were used as positive and negative controls, respectively. Overall, the results of the study indicated that both crude extracts exhibited antibacterial activity at higher concentrations.