Supplement
Clubmoss is a group of moss-like plants, including Huperzia serrata, whose alkaloid huperzine A slows the enzyme that breaks down acetylcholine, a brain messenger for memory. People mostly look at it for thinking skills in Alzheimer's disease, and trials of huperzine A found cognitive benefits, though the evidence is limited. Those trials used purified huperzine A rather than whole clubmoss, and most research on the herb itself was in animals or labs.
Sources: PMID 21821525; PMID 9141073
- Updated
- How we grade
- 15 studies cited
- Best evidence
- Grade C
- Conditions studied
- 2
- Outcomes
- 5
- Graded outcomes
- 0023
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
General
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Acetylcholinesterase Inhibition Multiple in vivo animal studies confirm that Huperzia alkaloid extracts inhibit acetylcholinesterase activity in brain tissue. Huperzia quadrifariata and H. reflexa alkaloids inhibited AChE in vivo in mice, and several related Huperzia species demonstrate comparable activity. The mechanism is well-established for Huperzine-A and supported for whole-herb preparations containing multiple lycopodium alkaloids. | Changes; see studies | Moderate effect | 6 studies | |||
Studies that measured acetylcholinesterase inhibition
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| Neuroprotection In vitro and animal studies show that Huperzine-A and other clubmoss alkaloids protect neurons against glutamate excitotoxicity, oxidative stress, and beta-amyloid-induced toxicity. These neuroprotective effects extend beyond acetylcholinesterase inhibition and involve multiple alkaloid constituents of Huperzia serrata. No human clinical data exists for neuroprotection with whole clubmoss extracts. | Improves (the measure goes up) | Small effect | 6 studies | |||
Studies that measured neuroprotection
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| Cognitive Function (Scopolamine-Induced Impairment) A 2015 study using Japanese Huperzia serrata extract (whole herb, not isolated Huperzine-A) ameliorated scopolamine-induced cognitive impairment in mice, suggesting the whole extract retains cholinergic cognitive-enhancing properties. This is one of the few studies using whole clubmoss extract rather than purified Huperzine-A. | Improves (the measure goes up) | Moderate effect | 5 studies | |||
Studies that measured cognitive function (scopolamine-induced impairment)
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| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Memory Enhancement in Healthy Adults A small number of studies suggest Huperzine-A may enhance memory in healthy young adults, particularly procedural memory. Evidence is limited, derived from isolated Huperzine-A rather than whole clubmoss extract, and requires replication in larger controlled trials. | Improves (the measure goes up) | Small effect | 5 studies | |||
Studies that measured memory enhancement in healthy adults
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Key findings
- Cognitive Function in Alzheimer's DiseaseImproves (the measure goes up)
- Acetylcholinesterase InhibitionChanges; see studies
- NeuroprotectionImproves (the measure goes up)
Safety notes in the studies
- In vitro and animal studies show that Huperzine-A and other clubmoss alkaloids protect neurons against glutamate excitotoxicity, oxidative stress, and beta-amyloid-induced toxicity.
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- Grade C
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Studies cited
15 studies from PubMed
- Anticholinesterase activity and identification of huperzine A in three Mexican lycopods.
- Pharmacological Effects of Active Components of Chinese Herbal Medicine in the Treatment of Alzheimer's Disease: A Review.
- Isolation, diversity and acetylcholinesterase inhibitory activity of the culturable endophytic fungi harboured in Huperzia serrata from Jinggang Mountain, China.
- Japanese Huperzia serrata extract and the constituent, huperzine A, ameliorate the scopolamine-induced cognitive impairment in mice.
- Huperzia quadrifariata and Huperzia reflexa alkaloids inhibit acetylcholinesterase activity in vivo in mice brain.
- Traditional Chinese medicines and Alzheimer's disease.
- Lycopodium alkaloids from Huperzia serrata.
- Huperzine A: a systematic review and meta-analysis of randomized clinical trials for Alzheimer's disease
- Huperzine A from Huperzia species--an ethnopharmacological review.
- Neuroprotective effects of huperzine A
- Is there a better source of huperzine A than Huperzia serrata? Huperzine A content of Huperziaceae species in China.
- Huperzine A attenuates cognitive deficits and brain injury in neonatal rats after hypoxia-ischemia
- New lycopodium alkaloids from Huperzia serrata.
- Huperzine A, a nootropic alkaloid, inhibits N-methyl-D-aspartate-induced current
- Huperzine A for memory deficits in Alzheimer's disease