Modification in the Composition of Lactuca sativa L. Plants Exposed to Abiotic Stress Induced by Commonly Used Antibiotics

The widespread worldwide use of antibiotics leads to significant diffuse pollution of the environment, but the understanding of the effects of many important antibiotics on plants is still limited. This study aimed to gain insight into the impact of ampicillin (AMP) and ciprofloxacin (CIP) on the bioactive compounds, antioxidant capacity, and elemental content of lettuce (Lactuca sativa L.). The lettuce was grown in a climate chamber under controlled conditions of light and temperature, in soil with contaminated antibiotics of different concentrations (7.5 mg kg−1—AMP I; 15 mg kg−1—AMP II; 30 mg kg−1—AMP III; 5 mg kg−1—CIP I; 10 mg kg−1—CIP II; and 20 mg kg−1—CIP III). The results obtained for the plants grown in the presence of antibiotics were compared with the control plants. Changing the growth conditions influenced the composition of the biologically active compounds and the content of elements selected in this study. Thus, it was observed that the plants grown with antibiotics exhibited a double increase in polyphenolic content, especially at higher treatment levels, but also a significant decrease in assimilatory pigments (up to 70.19%), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical-bleaching activity (up to 83.80%), and elemental contents compared to the control plants. Multivariate analysis was used to gain insight into similarities and differences between treatments and the association of the tested variables following the applied treatments, indicating a coping mechanism of the plants against the antibiotic treatments.