Table 6 Effect of the indole-N-alkyl and substitution patterns of the A-ring on the activity of compounds B and A. ^a↑, significantly increasing the activity relative to R = H; ↓, significantly decreasing the activity; ±, slight change of the activity. ^b“nd” means no determination.

From: New 2-Aryl-9-methyl-β-carbolinium salts as Potential Acetylcholinesterase Inhibitor agents: Synthesis, Bioactivity and Structure–Activity Relationship