Figure 4.

The synergistic effect of fangchinoline–coptisine pairs on AChE inhibition. (A): Fangchinoline (0.312–20 μM) and coptisine (0.156–10 μM) dose-dependently inhibited AChE in vitro. (B): Different ratios of fangchinoline–coptisine pairs (concentration ratio: 1:5, 1:2, 1:1, 2:1) dose-dependently inhibited AChE in vitro. The data was calculated by inhibitory percentage of control, and was expressed as Mean ± SEM, n = 3, each with triplicate samples. (C): Synergism analysis of fangchinoline–coptisine pairs (concentration ratio: 1:5, 1:2, 1:1, 2:1) was evaluated by median-effect principle. The AChE assay of fangchinoline, coptisine, and their combinations was performed as in Figure 3A, left. The synergism analysis of fangchinoline–coptisine pairs (concentration ratio: 1:5, 1:2, 1:1, 2:1) was performed as in Figure 3A, right.