Antibacterial activities of water extract of Vernonia amygdalina Delile leaves

Abstract

Staphylococci are common bacterial colonizers of the skin and mucous membranes of humans and other mammals. Staphylococcus epidermidis in particular is the most frequently isolated species from human epithelia. It colonizes predominantly the axillae, head, and nares. One type of medicinal plant that is nutritious for health is African leaves (Vernonia amygdalina Delile). Vernonia amygdalina extract showed the presence of some compounds which are rich in those constituents. The phytochemical screening of the extracts showed variation in their phytochemical constituents with the presence and or absence of some components. The presence of glycosides, alkaloids, and flavonoids was believed to exhibit the antibiotic properties of V. amygdalina leaves and confirmed their antimicrobial efficacy against selected pathogens. The concentration of 50 mg/mL up to a concentration of 1.56 mg/mL can inhibit the growth of S. epidermidis, the Minimum Inhibitory Concentration (MIC) itself is at the smallest concentration that has been able to inhibit bacterial growth and the number of bacteria is < 10 colonies. Staphylococcus epidermidis at a concentration of 25 mg/mL, absorbance values at wavelengths of 260 nm and 280 nm were higher than the absorbance values of S. epidermidis at a concentration of 12.5 mg/mL. The absorbance value at wavelengths of 260 nm and 280 nm will increase with the higher concentration of the extract, this indicates the presence of cell leakage observed in the presence of protein and nucleic acid leakage. S. epidermidis biofilm inhibition test shows that the results of the absorbance or OD (Optical Density) measurement in the biofilm inhibition test using the ethanol extract of V. amygdalina Delile, the OD value at a concentration of 25 mg/mL ie 0.149±0.004 showed a biofilm inhibition result of 62.37% greater than the concentration of 12.5 mg/mL which is 0.318±0.003 with a biofilm inhibition result of 19.52%, this indicates that the higher the concentration of the extract, the smaller the biofilm formation of S. epidermidis bacteria.