Figure 4.

Synergistic Caco-2 cell growth inhibition by the combination of α-pinene and myrcene. (a) Isobologram showing the interaction between α-pinene and myrcene in inhibiting cell growth of Caco-2 cells. Cells were treated for 72 h with α-pinene and/or myrcene and their viability was estimated with the SRB assay. Red symbols denote the IC₅₀ values of α-pinene (circle), myrcene (crossed circle), the combination of α-pinene’s IC₂₀ and myrcene (triangle), and the combination of myrcene’s IC₂₀ and α-pinene (crossed triangle). Green symbols denote the IC₃₀ values of α-pinene (square), myrcene (crossed square), the combination of α-pinene’s IC₂₀ and myrcene (triangle), and the combination of myrcene’s IC₂₀ and α-pinene (crossed triangle). Dashed lines indicate additive effects. Solid data points below the line of the same color, indicate a synergistic effect, whereas points above the line, indicate antagonism. (b) IC₃₀ and IC₅₀ values of the different combinations of myrcene and α-pinene, and the estimated combination index values.