Comparative evaluation of anticancer and antimicrobial potential of Diplotaxis tenuifolia plant extracts obtained by different extraction methods

After plants appeared on earth, they settled at the first step of the food pyramid, especially in terrestrial ecosystems, and became the source of carbon, which is the basis of life for heterotrophic creatures. Since the earliest times of history, people have used plants for various purposes, studied them, and made efforts to introduce them. In this thesis study, the anticancer, antimicrobial, and anti-Quorum Sensing (anti-QS) activities of ethyl acetate (EA), methanol (MeOH), and water extracts isolated from the aerial parts of the Diplotaxis tenuifolia plant by maceration and ultrasonication methods were investigated. The anticancer activity of the tested extracts was evaluated by the MTT method on PC-3 and MDA-MB-231 cancer cell lines. Their antibacterial activities were investigated by disk diffusion and broth microdilution methods against six Gram-negative, three Gram-positive bacteria and one yeast strain representing human pathogens. The anti-QS activities of the extracts were tested using the semi-solid agar method for their inhibitory activity on violacein pigment production in the Chromobacterium violaceum CV026 biosensor strain, and the crystal violet method for their anti-biofilm activity against the Staphylococcus aureus ATCC 25923 strain. As a result, the lowest survival rate (2.0%-2.8%) for both cell lines at the end of 48 hours was determined at 1000 µg/mL concentration of EA extracts. IC50 values were calculated as 304.4 µg/mL and 313 µg/mL against MDA-MB-231 and PC-3 cell lines, respectively. It was determined that only the EA extract of the plant prepared by the ultrasonication method created zone diameter against Bacillus subtilis at the concentrations studied. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined as 1000 µg/mL each. While no inhibitory activity was observed on violacein pigment production, it was determined that the extracts inhibited biofilm formation by up to 81.9%. In further studies, it is recommended to perform phytochemical analysis of the extracts and determine which compound or compounds are responsible for the biological activities.