The top three derivatives, Xylopine_2, Rosmaricine_14 and Rosmaricine_15, have in common a pyridinium addition to their native structure ( Figure 2) . The pyridinium addition could be the main explanation for higher DockScores of these three derivatives compared to their native compounds and the other derivatives. Rosmaricine_14 and Rosmaricine_15 differed by the number of fused rings, but the slight difference in DockScore suggests that addition of an acyclic ring has little influence on binding affinity.