Figure 3.

Isobolograms of combination of ferulic acid with Z-ligustilide in inhibiting [Ca²⁺]_i response to agonists. The individual doses of ferulic acid and Z-ligustilide to achieve 90% (straight line) inhibition (Fa = 0.90), 75% (hyphenated line) inhibition (Fa = 0.75), and 70% (crosses) inhibition (Fa = 0.70) were plotted on the x-axes and y-axes. Combination index (CI) values calculated by Calcusyn software are represented by points above (indicating antagonism) or below the lines (indicating synergism).