ACHE and Alzheimer disease: Research shows that Tanshinone IIA not only decreases acetylcholinesterase (AChE) activity, elevates acetylcholine (ACh) levels, improves cholinergic neuronal function, and enhances choline acetyltransferase (ChAT) activity, but it also effectively promotes neurogenesis and significantly increases the expression of the synaptic marker PSD-95 (a protein closely related to learning and memory) in an Alzheimer’s disease (AD) mouse model.