Cholinesterase Inhibiting Ability of Cymserine


Cymserine is an experimental drug with a potent reversible cholinesterase inhibiting properties, which is currently being investigated for its potential for the treatment of Alzheimer’s disease and some types of dementia. The drug is related to physostigmine, a parasympathomimetic alkaloid that occurs naturally in the Calabar bean that is endemic to Western Africa.

Cymserine has been observed in studies to have the ability to inhibit cholinesterase enzymes from being produced in the brain. This ability was also seen to have a moderate inhibiting selectivity for the enzyme butyrylcholinesterase, and a weaker inhibiting ability against the enzyme acetylcholinesterase. These two enzymes cause the degradation of acetylcholine, an important neurotransmitter in the brain that is responsible for most of the cognitive processes within the brain.

Some degenerative neurological conditions such as Alzheimer’s disease are usually typified by a neurotransmitter deficiency due to cholinergic loss. This has led to the development of cholinesterase inhibiting drugs that have moderate success in delaying the progression of the disease. However, the early cholinesterase inhibiting drugs, which are nonselective like Donepezil have adverse effects like salivation, lacrimation, and tremor.  The selective cholinesterase inhibiting properties of Cymserine, makes it a better alternative because it does not trigger the same side effects as the nonselective cholinesterase inhibitors.

The selective cholinesterase inhibiting ability of cymserine has led to the development of cymserine derivatives that has a greater selectivity for the enzyme butyrylcholinesterase. Studies on Cymserine and its analogue derivatives have been conducted on laboratory animals and it has been observed to have cognitive enhancing abilities. What makes the initial studies on laboratory animals interesting is that Cymserine, along with its analogue derivatives have also shown the ability to reduce the levels of amyloid beta and amyloid precursor protein, which are indicators of an impending affliction of Alzheimer’s disease.

CymserineThe cognitive enhancing effect of Cymserine is attributed to an increased acetylcholine levels in the brain. This ability of Cymserine speaks volumes for the potential of the drug as a cognitive enhancer, not only for individuals suffering from neurological conditions, but for regular nootropic users who are constantly on the lookout for better and more potent nootropic agents to try.

Among the analog derivatives of Cymserine include the following:


Studies on this Cymserine derivative showed a stronger cholinesterase inhibiting properties against the enzyme butyrylcholinesterase. The studies determined that the Dihydrobenzodioxepine Cymserine derivative has a higher potency that Cymserine, indicating that it could be a better alternative for the treatment and management of Alzheimer’s disease.


This analogue derivative of Cymserine has also shown potent inhibiting properties against the butyrylcholinesterase enzyme. People suffering from Alzheimer’s disease have elevated levels of butyrylcholinesterase enzymes in the brain, which means that selective inhibition of this particular enzyme can increase the levels of the neurotransmitter acetylcholine in the brain. The potency of Tetrahydrofurobenzofuran Cymserine as a butyrylcholinesterase enzyme inhibitor is comparable to its isomer, dihydrobenzodioxepine cymserine.

Other Cymserine derivatives that are currently being studied include Bisbenzylnorcymserine. Norcymserine, and Bisnorcymserine. It must be noted that most of the studies on Cymserine and its derivatives are focused mainly on its inhibiting effect on butyrylcholinesterase and its potential for treating or preventing cognitive impairments associated with Alzheimer’s disease and aging. There are currently no studies that impart any information regarding the efficacy of Cymserine as a cognitive enhancing agent for healthy subjects.

Some animal studies have also shown that Cymserine that have several advantages over other experimental cognitive enhancers that are also currently in development. The studies have shown that Cymserine has a high bioavailability and that it can cross the blood-brain barrier easily. With this advantage of Cymserine over other experimental nootropic agents, it would be reasonable to assume that its testing phase and subsequent release to the public may come sooner than the other compounds being studied. That is of course, if Cymserine is able to carry over the results from the animal studies into the human trials phase.

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