## 3 Results and Discussion
The green line with triangles corresponds to the expected activity values for the tested pairs of compounds. The experimental values are the mean values for \(n=5\). Tables 2-5 present the results of statistical analysis obtained for the differences between the inhibition percent determined experimentally (Ie) and the percentages of theoretical inhibition (Ic) being the sum of the inhibition percent determined for single antioxidants (for a solution in which the amount of the component, i.e., chlorogenic acid or kaempfer, corresponds to the amount present in the mixture). The tables contain data obtained for % of inhibition determined at different volume ratios of antioxidants in their mixture. In the interpretation of the results aimed at determining the resultant antioxidant effect of the mixture, it was assumed that the lack of a significant difference between the Ie and Ic values indicates the additive antioxidant effect of the mixture containing chlorogenic acid and kaempfer. On the other hand, statistically significant differences (_Fcal_ > _Fcrit_) indicate an antagonistic or synergistic antioxidant effect of the mixture. In the case of the first of the two mentioned effects, there is a negative value of the difference between Ie and Ic, while its positive value is responsible for the second effect. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Temperature (\({}^{\circ}\)C)** & **System Number** & **Volume Ratio (\(r\)/\(v\))** & **F–Values** & **\(p\)-Values** & **(Ie-Ic)-Values** & **Observed Effect** \\ \hline  & 7 & 20/80 & 34.91 & 0.0041 & negative & antagonism \\
15 & 8 & 50/50 & 40.19 & 0.0032 & negative & antagonism \\  & 9 & 80/20 & 56.49 & 0.0002 & negative & antagonism \\ \hline  & 7 & 20/80 & 13.83 & 0.0205 & negative & antagonism/additivism \\
25 & 8 & 50/50 & 11.03 & 0.0293 & negative & antagonism/additivism \\  & 9 & 80/20 & 21.07 & 0.0101 & negative & antagonism \\ \hline  & 7 & 20/80 & 34.47 & 0.0042 & negative & antagonism \\
35 & 8 & 50/50 & 47.33 & 0.0023 & negative & antagonism \\  & 9 & 80/20 & 56.98 & 0.0016 & negative & antagonism \\ \hline \end{tabular}
\end{table} 
Table 2: Statistical significance (\(F\) and \(p\) values) of the difference between the experimental inhibition percent (Ie) and calculated inhibition percent (Ic) for the binary mixtures of the chlorogenic acid and kaempfer at three different volume ratios and at three different temperatures, together with the difference (Ie-Ic) and with the observed effect (the resultant) antioxidant effect of the antioxidants in the mixture (\(F_{\textit{crit}}\) = 7.71). Figure 3: The antioxidant activity changes assessed by the ABTS method for the systems containing different volumes of methanolic solutions (**A**) and methanolic with water addition (**B**) solutions of chlorogenic acid (red line with squares) and kaempfer (blue line with diamonds), and their binary mixtures (violet line with “x”). The green line with triangles corresponds to the expected activity values for the tested pairs of compounds. The experimental values are the mean values for \(n=5\). Figure 4: Changes in antioxidant activity assessed by the ABTS method for systems containing different volumes of methanol solutions of chlorogenic acid (red line with squares), kaempfer (blue line with diamonds) and their binary mixtures (violet line with “x”), with the addition of water (**A**), ions iron (**B**), copper ions (**C**), buffer with pH = 1 (**D**) and buffer with pH = 3 (**E**). The green line with triangles corresponds to the expected activity values for the tested pairs of compounds. Experimental values are mean values for \(n=5\).