(A) Effect
of coumarin on the violacein production in C. violaceum 12472. The combined df and F values
are 5 and 121.945, respectively. (B)
Effect of coumarin on the prodigiosin production and exoprotease activity S. marcescens MTCC 97. The combined df and F values for prodigiosin production are 4 and
248.452, respectively. The combined df and F values for exoprotease activity are 4 and 145.625, respectively.
Different letters above the error bars represent different significance
groups by the Tukey test at p-value = 0.05. Data
are represented as mean values of triplicate readings, and the bar
is standard deviation. The percent inhibition is shown on the secondary y-axis. (C) Swarming motility of S. marcescens MTCC 97. (i) Untreated control, (ii) 62.5, (iii) 125, and (iv) 250
μg/mL.