The enzyme-inhibitory effects of Onosma species were evaluated against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), enzymes implicated in neurodegenerative disorders such as Alzheimer’s disease, as well as α-amylase and α-glucosidase, which are involved in carbohydrate digestion and associated with metabolic disorders like diabetes. Here, ACHE is linked to early-onset autosomal dominant Alzheimer disease.