Cholinesterase inhibitors from Sargassum and Gracilaria gracilis: seaweeds inhabiting South Indian coastal areas (Hare Island, Gulf of Mannar).

Dementia is a chronic progressive mental disorder, which adversely affects memory, thinking, comprehension, calculation and language. Some of the commonest forms of dementia are Alzheimer's disease, Parkinsonism, Dementia with Lewy Bodies and Myasthenia gravis. All these disorders are related to abnormalities in the central cholinergic system, which shows a decline in acetylcholine level.