A small scale double-blind randomized controlled trial carried out by the Iranian team of Fatemeh Dabaghzadeh and co-workers looked at the effect in healthy subjects of Rosemary (Salvia rosmarinus Spenn.) powder taken by mouth on acetyl cholinesterase (AChE) activity and biomarkers of oxidative stress.
Rosemary is used traditionally in some cultures to improve memory. Combined antioxidant and AChE-inhibitory effects might suggest its potential application against Alzheimer’s disease.
In the present study, 1000 mg/day of rosemary powder was found to increase total antioxidant activity and decrease acetylcholinesterase (AChE) activity.
Decreased AChE activity means increased activity in cholinergic neurons; thus, contrary to the paper’s draft title (below), rosemary does not have an anticholinergic effect but a cholinergic one. When I pointed this out to the authors they agreed that it is a mistake and will correct it before going to press.
The dysfunction and loss of basal forebrain cholinergic neurons and their cortical projections are among the earliest pathological events in Alzheimer’s disease (Wikipedia).
Dabaghzadeh F et al. (2021). Antioxidant and anticholinergic effects of rosemary extract: a double-blind randomized controlled trial. Advances in Integrative Medicine. In-Press, Journal Pre-Proof. Available online 3 April 2021. Retrieved 19 April 2021.