(?)-Nicotine is the dominant form of the natural alkaloid nicotine. It acts as an agonist of neuronal nicotinic acetylcholine receptors (nAChRs) and possesses addictive and teratogenic properties. (?)-(S)-Nicotine is significantly more active at binding nAChRs compared to the (+)-(R) antipode thus nicotine is typically synthesized as (?)-(S)-nicotine with only 0.2-1% of the (+)-(R) isomer present.

Isorosmanol is an abietane-type diterpene isolated from Rosmarinus officinalis L. aerial parts, with antioxidant, neuroprotective and neurotrophic effects. Isorosmanol inhibits AChE activity and melanin synthesis.

6-Ethoxydihydrosanguinarine shows human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity, with IC50 values of 0.83 +/- 0.04 microM and 4.20 +/- 0.19 microM, respectively.