Monardic acid A is a selective inhibitor of AChE, with an IC50 of 53.1 μM against AChE derived from electric eels. It shows weak inhibitory activity on human erythrocyte AChE (IC50>100 μM) and has no significant effect on BChE. By inhibiting AChE activity, Monardic acid A decreases acetylcholine breakdown while also inhibiting histamine release and hyaluronidase activity, contributing to its anti-inflammatory and neurotransmitter-regulating properties. It can be isolated from lungwort (Pulmonaria officinalis) and thyme (Thymus gobicus) and is primarily used in the development of anti-inflammatory drugs and treatments for neurodegenerative diseases.