Anticancer, Antibiofilm, Antimicrobial Effects and Anti-Quorum Sensing Inhibition Potentials of Alchemilla oriturcica and Helichrysum armenium Extracts

This study investigated the anticancer, antimicrobial, and anti-quorum sensing (anti-QS) potentials of methanol (MeOH) and ethyl acetate (EtOAc) extracts of Alchemilla oriturcica and Helichrysum armenium flowers. Antimicrobial activity was analyzed by the agar diffusion method using nine gram-negative and five gram-positive bacteria, and two yeasts. Anticancer activity was assessed by MTT assay using several cell lines. Anti-QS features of the extracts were determined by violacein production inhibition of Chromobacterium violaceum strains, and by inhibition of biofilm formation of Pseudomonas aeruginosa PAO1 strain. The anticancer results of the study showed that the H. armenium extracts were cytotoxic to normal and cancer cells tested at concentrations over 400 μg/mL, and HT29 colon cancer cell line was the most sensitive. While the A. oriturcica methanol extract showed dose-dependent cytotoxic effects on normal and cancer cells, the most significantly inhibited cell lines at ≤300 µg/mL concentrations were A549 and HeLa cells.