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A significant improvement came from the introduction of a palladium-catalyzed bicycloannulation by Campiani et al in 1993. This transformation provided the intermediate 25, which was readily converted to ()-huperzine A (Figure 8A).75 Using 2-methylene-1,3-dipropanediol acetate (24) as electrophile, the bicycloannulation proceeded smoothly in the presence of 5 mol% palladium acetate, TMG, and triphenylphosphine to provide the tricyclic product 25 in 92% yield. The tricyclic product 25 could be transformed to ()-huperzine A in five steps.
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In 2002, Lee et al described a formal synthesis of ()-huperzine A. A key step in their synthesis involved the manganese-mediated oxidative cyclization of the β-ketoester 8 (Figure 9A).78 The α-quaternary ketone 30 was obtained by alkylation of the β-ketoester 8 with 3-bromo-2-methylprop-1-ene (29). Treatment of 30 with excess manganese acetate and one equivalent of copper acetate formed a mixture of the exocylic olefin 25 (40%) and the endocyclic olefin 27 (21%).
Ward and Caprio prepared the selenide 32 in five steps and 17% yield from 5-bromo-6-methyl-2-methoxypyridine (31; Figure 9B).79 A pyridyl radical was formed by treatment with tributyltin hydride (n-Bu3SnH) and azobisisobutyronitrile; subsequent 6-exo-trig cyclization produced the alcohol 33 (46%) along with the reduction product 34 (54%). Ward and Caprio80 and Ward et al81 further demonstrated this methodology with several structurally-related precursors. However, the synthesis of ()-huperzine A has yet to be completed by this route.
Huperzine-A is a natural alkaloid extract of Huperzia serrata, a Chinese plant. It has been used for centuries in traditional Chinese medicine for treating senile dementia. You can now enjoy its benefits in a supplement form with vegetarian capsules, available to buy in Supersmart's online catalogue.
Just like certain drugs, huperzine-A inhibits the enzyme acetylcholinesterase which breaks down acetylcholine, a neurotransmitter essential for optimal cognitive function. The amount of acetylcholine available in the brain is therefore greater. Unlike drugs, huperzine-A:
Supplementation of huperzine-A tends to be in the range of 50-200mcg daily, and while this can be divided into multiple dosages throughout the day it tends to be taken at a single dose. Supplementation of huperzine-A does not require food to be coingested with it and can be taken in a fasted state.
Cycling of huperzine-A tends to be used since it can remain in the body for quite some time (half-life of 10-14 hours), and although a 'cycle' of huperzine-A tends to last 2-4 weeks followed by a break the optimal cycle length is not yet known.
Researchers observed no severe side effects in the huperzine A treated patients. Blood pressure, heart rate, electrocardiogram, electroencephalogram, liver and urine tests did not show any major abnormalities.(3)
Neurites are the tiny projections that make connections between brain cells, allowing messages to be transmitted. Huperzine A has been shown to promote the growth of neurites. In one study, researchers found that after just 48 hours of treatment with huperzine A, the number of brain cell neurites increased dramatically. (1)
These impressive results indicate that huperzine A is an all-around brain-enhancing phytonutrient that strengthens nerve cells, prevents neurotransmitter breakdown, improves neuronal communication, and protects healthy brain cells from the damaging effects of free radicals.
Huperzine A (1, Hup A), a lycodine-type Lycopodium alkaloid isolated from Thai clubmosses Huperzia squarrosa (G. Forst.) Trevis., H. carinata (Desv. ex. Poir.) Trevis., H. phlegmaria (L.), and Phlegmariurus nummulariifolius (Blume) Chambers (Lycopodiaceae), exerts inhibitory activity on acetylcholinesterase, a known target for Alzheimer's disease therapy. This study investigated the structure-activity relationship of C(2)-functionalized and O- or N-methyl-substituted huperzine A derivatives. In silico-guided screening was performed to search for potential active compounds. Molecular docking analysis suggested that substitution at the C(2) position of Hup A with small functional groups could enhance binding affinity with AChE. Consequently, 12 C(2)-functionalized and four O- or N-methyl-substituted compounds were semi-synthesized and evaluated for their eeAChE and eqBChE inhibitory activities. The result showed that 2-methoxyhuperzine A (10) displayed moderate to high eeAChE inhibitory potency (IC50 = 0.16 μM) with the best selectivity over eqBChE (selectivity index = 3633). Notably, this work showed a case of which computational analysis could be utilized as a tool to rationally screen and design promising drug molecules, getting rid of impotent molecules before going more deeply on labor-intensive and time-consuming drug discovery and development processes.
N2 - Huperzine A (1, Hup A), a lycodine-type Lycopodium alkaloid isolated from Thai clubmosses Huperzia squarrosa (G. Forst.) Trevis., H. carinata (Desv. ex. Poir.) Trevis., H. phlegmaria (L.), and Phlegmariurus nummulariifolius (Blume) Chambers (Lycopodiaceae), exerts inhibitory activity on acetylcholinesterase, a known target for Alzheimer's disease therapy. This study investigated the structure-activity relationship of C(2)-functionalized and O- or N-methyl-substituted huperzine A derivatives. In silico-guided screening was performed to search for potential active compounds. Molecular docking analysis suggested that substitution at the C(2) position of Hup A with small functional groups could enhance binding affinity with AChE. Consequently, 12 C(2)-functionalized and four O- or N-methyl-substituted compounds were semi-synthesized and evaluated for their eeAChE and eqBChE inhibitory activities. The result showed that 2-methoxyhuperzine A (10) displayed moderate to high eeAChE inhibitory potency (IC50 = 0.16 μM) with the best selectivity over eqBChE (selectivity index = 3633). Notably, this work showed a case of which computational analysis could be utilized as a tool to rationally screen and design promising drug molecules, getting rid of impotent molecules before going more deeply on labor-intensive and time-consuming drug discovery and development processes.
AB - Huperzine A (1, Hup A), a lycodine-type Lycopodium alkaloid isolated from Thai clubmosses Huperzia squarrosa (G. Forst.) Trevis., H. carinata (Desv. ex. Poir.) Trevis., H. phlegmaria (L.), and Phlegmariurus nummulariifolius (Blume) Chambers (Lycopodiaceae), exerts inhibitory activity on acetylcholinesterase, a known target for Alzheimer's disease therapy. This study investigated the structure-activity relationship of C(2)-functionalized and O- or N-methyl-substituted huperzine A derivatives. In silico-guided screening was performed to search for potential active compounds. Molecular docking analysis suggested that substitution at the C(2) position of Hup A with small functional groups could enhance binding affinity with AChE. Consequently, 12 C(2)-functionalized and four O- or N-methyl-substituted compounds were semi-synthesized and evaluated for their eeAChE and eqBChE inhibitory activities. The result showed that 2-methoxyhuperzine A (10) displayed moderate to high eeAChE inhibitory potency (IC50 = 0.16 μM) with the best selectivity over eqBChE (selectivity index = 3633). Notably, this work showed a case of which computational analysis could be utilized as a tool to rationally screen and design promising drug molecules, getting rid of impotent molecules before going more deeply on labor-intensive and time-consuming drug discovery and development processes. 041b061a72