Investigation of in vitro cytotoxic potential of water extract of Wiedemannia orientalis

Studies on the biological activities of plants are gaining momentum nowadays. There is no detailed study in the literature examining the biological activities of Wiedemannia orientalis Fisch. & Mey. species in the Lamiaceae family. This thesis aimed to determine the cytotoxic effects of water extracts of the root, stem, leaf, and flower parts of W. orientalis against breast cancer cell lines, antibacterial activities against bacteria representing human pathogens, and quorum sensing inhibitory effects against some bioindicator strains. For this purpose, the cytotoxic effects of the extracts on MCF-7 and MDA-MB-231 cell lines were investigated by the MTT method. The antibacterial activity was investigated against ten Gram-negative and three Gram-positive bacteria using the broth microdilution method. The anti-QS activities of the extracts were studied using the soft agar method and the crystal violet method on violacein pigment inhibition in Chromobacterium violaceum ATCC 12472 and on biofilm formation inhibition in Pseudomonas aeruginosa PAO1, respectively. The extracts did not exhibit significant cytotoxic activity against the MDA-MB-231 cell line. However, the extracts showed varying degrees of cytotoxic activity against the MCF-7 cell line. In particular, the root extract showed the most potent cytotoxic activity (IC50=589.3 µg/mL). In contrast, the extracts did not exhibit antibacterial activity (MIC>500 µg/mL) at the concentrations studied, and violacein did not inhibit pigment production. All extracts inhibited biofilm formation at varying rates. In particular, the flower extract inhibited biofilm formation at the highest rate (44.5%). The results showed that especially the root and flower extracts of the W. orientalis might contribute to the development of anticancer and anti-biofilm agents, respectively.