Huperzina A jest inhibitorem acetylo esterazy, która powoduje rozpad acetylocholiny, to tak po krótce. Tu większe info ze strony supplementwatch:
Supplement Huperzine A
Description Huperzine A, is a purified alkaloid extract from a Chinese moss,
Huperzia serrata (as such, it is really more of a “naturally derived drug” than a true herbal remedy) The moss has been used in Traditional Chinese Medicine for treating fever, inflammation, schizophrenia and memory loss. As a modern herbal supplement, Huperzine A (HupA) is used therapeutically to treat Alzheimer's disease and other age-associated memory impairments.
Claims Improves memory
Enhances learning ability
Treats senile dementia and Alzheimer’s disease
Theory The theory for how HupA may work has to do with a specific neurotransmitter called acetylcholine. Acetylcholine is released into the space between two nerve cells (the synapse), where it stimulates a “transfer” of the nerve impulse from one nerve cell to the next. After the nerve impulse has been transmitted, an enzyme called acetylcholine esterase breaks down acetylcholine and the nervous signal is ended. In some memory disorders, such as Alzheimer’s disease and senile dementia, acetylcholine may be destroyed too quickly – so the nerve impulse is either too weak to be received or it id incompletely transmitted between nerve cells. HupA seems to inhibit the activity of acetylcholine esterase – so the breakdown of acetylcholine is slowed and the strength and duration of the nerve impulse is improved. This inhibition of acetylcholine breakdown may be the reason for the effect of HupA on improving memory and overall cognitive processes.
Scientific Support The effects of HupA have been investigated in laboratory and clinical settings – with the overall findings that HupA is known to be a potent, reversible and selective inhibitor of acetylcholine esterase, with a rapid absorption and penetration into the brain in animal tests. It exhibits memory-enhancing activities in animal and clinical trials. Compared to existing medications for the treatment of Alzheimer’s disease, such as tacrine, physostigmine and donepezil, HupA possesses a longer duration of action and higher therapeutic index, and the peripheral cholinergic side effects are minimal at therapeutic doses. HupA may also reduce neuronal cell death caused by glutamate – an action that further enhances the potential value of HupA as a therapeutic agent for Alzheimer’s disease
In animal studies, daily oral administration of huperzine A has been shown to produce a significant improvement in learning ability (maze tasks) that is strongly correlated to promotion of blood flow and inhibition of acetylcholinesterase activity in various regions of the brain (cortex and hippocampus).
In humans, the effects of HupA are considered a promising therapeutic agent for Alzheimer's disease and memory deficit. In one study of 103 patients with Alzheimer's disease, (multi-center, prospective, double-blind, parallel, placebo controlled and randomized), 50 received 200mcg of HupA and 53 received a placebo for 8 weeks. Study results showed that about 58% (29/50) of patients treated with HupA showed significant improvements in their memory, cognitive and behavioral functions versus only 36% of those receiving the placebo. No adverse side effects were reported. In another study of teenage Chinese students, the effect HupA on memory and learning performance was studied using a double-blind, matched pair, placebo controlled design in which 34 pairs of students complaining of memory inadequacy were given HupA (100mcg HupA, taken twice per day) or a look-alike placebo for 4 weeks. At the end of trial, the students receiving HupA had significantly higher scores on tests of memory (memory quotient) compared to the placebo group.
Safety The reported side effects for HupA are generally quite mild such as dizziness and headaches. However, because no long-term safety studies have been conducted, children and women who are pregnant or nursing should avoid HupA except on the specific advice and guidance of a physician (animal studies have shown that HupA can pass from mother to fetus). There have also been isolated reports of possible liver and kidney toxicity associated with raw preparations of the Huperzine moss, so a purified extract is recommended. Huperzine occurs in 2 forms, “A” and “B” as well as 2 enantiomers (-) and (+). The most biologically active form of Huperzine is (-)HuperzineA – so look for it on the label (often branded as “Memorzine”).
Value As a treatment for Alzheimer’s disease, dementia, age-associated memory impairment and senile memory disorders, HupA has shown some impressive results with virtually no side effects. The popularity of other “memory” and “brain” herbals, such as ginkgo biloba, ginseng, and 5HTP attest to the fact that this is an area of great concern to many people – and the typical price for HupA preparations is quite reasonable at less than $1 per day.
Dosage Typical dosage recommendations for purified and standardized HupA extracts are 50mcg, taken twice per day, although doses of 30-200mcg per day have been used in clinical studies to treat Alzheimer’s disease, dementia, age-associated memory impairment and senile memory disorders.
References 1. Ashani Y, Grunwald J, Kronman C, Velan B, Shafferman A. Role of tyrosine 337 in the binding of huperzine A to the active site of human acetylcholinesterase. Mol Pharmacol. 1994 Mar;45(3):555-60.
2. Ashani Y, Peggins JO 3d, Doctor BP. Mechanism of inhibition of cholinesterases by huperzine A. Biochem Biophys Res Commun. 1992 Apr 30;184(2):719-26.
3. Bai DL, Tang XC, He XC. Huperzine A, a potential therapeutic agent for treatment of Alzheimer's disease. Curr Med Chem. 2000 Mar;7(3):355-7
-74. 4. Geib SJ, Tuckmantel W, Kozikowski AP. Huperzine A--a potent acetylcholinesterase inhibitor of use in the treatment of Alzheimer's disease. Acta Crystallogr C. 1991 Apr 15;47 ( Pt 4):824-7.
5. Patocka J. Huperzine A--an interesting anticholinesterase compound from the Chinese herbal medicine. Acta Medica (Hradec Kralove). 1998;41(4):155-7.
6. Pepping J. Huperzine A. Am J Health Syst Pharm. 2000 Mar 15;57(6):530, 533-4.
7. Pilotaz F, Masson P. Huperzine a: an acetylcholinesterase inhibitor with high pharmacological potential. Ann Pharm Fr. 1999 Sep;57(5):363-73.
8. Saxena A, Qian N, Kovach IM, Kozikowski AP, Pang YP, Vellom DC, Radic Z, Quinn D, Taylor P, Doctor BP. Identification of amino acid residues involved in the binding of Huperzine A to cholinesterases. Protein Sci. 1994 Oct;3(10):1770-8.
9. Sun QQ, Xu SS, Pan JL, Guo HM, Cao WQ. Huperzine-A capsules enhance memory and learning performance in 34 pairs of matched adolescent students. Chung Kuo Yao Li Hsueh Pao. 1999 Jul;20 (7):601-3.
10. Tang XC. Huperzine A (shuangyiping): a promising drug for Alzheimer's disease. Chung Kuo Yao Li Hsueh Pao. 1996 Nov;17(6):481-4.
11. Wang LM, Han YF, Tang XC. Huperzine A improves cognitive deficits caused by chronic cerebral hypoperfusion in rats. Eur J Pharmacol. 2000 Jun 9;398(1):65-72.
12. Xiao XQ, Wang R, Han YF, Tang XC. Protective effects of huperzine A on beta-amyloid(25-35) induced oxidative injury in rat pheochromocytoma cells. Neurosci Lett. 2000 Jun 9;286(3):155-8.
13. Xu SS, Cai ZY, Qu ZW, Yang RM, Cai YL, Wang GQ, Su XQ, Zhong XS, Cheng RY, Xu WA, Li JX, Feng B. Huperzine-A in capsules and tablets for treating patients with Alzheimer disease. Chung Kuo Yao Li Hsueh Pao. 1999 Jun;20(6):486-90.
14. Xu SS, Gao ZX, Weng Z, Du ZM, Xu WA, Yang JS, Zhang ML, Tong ZH, Fang YS, Chai XS, et al. Efficacy of tablet huperzine-A on memory, cognition, and behavior in Alzheimer's disease. Chung Kuo Yao Li Hsueh Pao. 1995 Sep;16(5):391-5.
15. Zhang RW, Tang XC, Han YY, Sang GW, Zhang YD, Ma YX, Zhang CL, Yang RM. Drug evaluation of huperzine A in the treatment of senile memory disorders. Chung Kuo Yao Li Hsueh Pao. 1991 May;12(3):250-2.
16. Zhu XZ. Development of natural products as drugs acting on central nervous system. Mem Inst Oswaldo Cruz. 1991;86 Suppl 2:173
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