Evaluation of total phenol and flavonoid contents, antioxidant and antimicrobial activity of Lawsonia inermis aqueous extract against some gram- positive and gram- negative bacteria

The toxic effects of synthetic antimicrobial and antioxidant compounds have led to an increase in the use of natural types, such as plant extracts. In this study, the antimicrobial effect of Lawsonia inermis aqueous extract was investigated against Escherichia coli, Salmonella typhimurium, Staphylococcus epidermidis, and Listeria innocua, by disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods. The higher concentrations of the extract showed higher antimicrobial effects against S. epidermidis and L. innocua compared to E. coli and S. typhimurium. Moreover, the total phenolic and flavonoids contents of the extract were 59.45±1.12 mg gallic acid per gram of extract and 40.35±0.70 mg quercetin per gram of extract, respectively. The antioxidant properties of aqueous extract were measured based on the DPPH and ABTS free radical scavenging activities. It was found that the antioxidant activity increased significantly as a function of L. inermis aqueous extract concentration. The antimicrobial and antioxidant properties of L. inermis leaf aqueous extract could make it a natural bioactive compound to be used as in food and medicinal products.