THE INFLUENCE OF EXPIRED MEDICINES ON PLANT PHOTOSYNTHESIS PARAMETERS AND CHLOROPHYLL PIGMENTS

Abstract

This study examines the influence of expired pharmaceuticals on Brassica oleracea var. Buzau, grown at three
different CO2 concentrations, focusing on photosynthetic parameters and chlorophyll pigment concentrations. Active
pharmaceutical ingredients (APIs) and excipients in expired drugs pose significant environmental and public health risks
through improper disposal, leading to soil and water contamination. Pharmaceuticals in the soil significantly impact
plant photosynthesis, reducing net assimilation rates and stomatal conductance. Additionally, they cause a marked
decrease in chlorophyll a and b concentrations due to toxic effects that degrade chlorophyll and inhibit its biosynthesis.
However, an increase in zeaxanthin concentration suggests an adaptive response to oxidative stress. While total phenol
concentrations remain relatively unaffected, flavonoid levels significantly decline, disrupting secondary plant
metabolism. Elevated CO2 levels can stimulate phenolic compound synthesis, partially offsetting the negative impacts of
pharmaceuticals. The antioxidant activity of plants is also compromised, as indicated by altered inhibition percentages
due to reduced phenol concentrations essential for soil microbial activity and chemical reactions. These findings highlight
the need for understanding the combined effects of pharmaceuticals and elevated CO2 on plant health and stress the
importance of managing soil contamination to protect ecological health and agricultural productivity.