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In
a 2003 double-blind, randomized study, Huperzine A, in injectable
form, was tested against a saline control in 56 patients with
multi-infarct dementia or senile dementia and in 104 patients with
senile and pre-senile simple memory disorders. Huperzine A produced
significant positive effects as measured by the Wechsler Memory
Scale. Dizziness was experienced by a few of the Huperzine A-treated
patients (He XC, Yu GL, Bai DL. Studies on
analogues of huperzine A for treatment of senile dementia. VI.
Asymmetric total synthesis of 14-nor-huperzine A and its inhibitory
activity of acetylcholinesterase. [Article in Chinese] Yao Xue Xue
Bao. 2003;38(5):346-349).
In
another study, this one multicenter, double-blind, placebo-controlled
and randomized, 50 subjects with Alzheimer's disease were given
Huperzine A or placebo for eight weeks. Significant improvement was
noted in 58 percent of the patients in terms of memory, cognitive and
behavioral functions. Research is ongoing (Xu
SS, Cai ZY, Qu ZW, et al. Huperzine-A in capsules and tablets for
treating patients with Alzheimer disease. Zhongguo Yao Li Xue Bao.
1999;20(6):486-490).
Toxicology
and efficacy studies of Huperzine A show it to be non-toxic even when
administered at 50-100 times the human therapeutic dose. The extract
is active for 6 hours at a dose of 2 µg/kg with no remarkable
side effects.
In
relation to Alzheimer’s disease, double blind controlled studies of
over 160 patients, showed significant improvement measured by
Weschler scale results, at doses of only 150 µg given twice
daily (3-5 µg/kg) (Xu SS, Gao ZX, Weng Z, et al. Efficacy of
tablet huperzine-A on memory, cognition and behavior in Alzheimer's
disease. Chung Kuo Yao Li Hsueh Pao. 1995; 16:391-395).
In
1999, Chinese researchers found, in a study designed to determine the
efficacy of HuperzineA on memory and learning in adolescents, that
similar results were observed to trila swith adults. They selected 34
matched pairs of apparently normal junior middle school students
whose only significant complaints were of poor memory and difficulty
in learning. The pairing was done in terms of age, sex, memory
quotient, and overall psychological health, to ensure that
comparisons would be meaningful. Using these criteria, the
researchers found no statistically significant baseline differences
between the students in the two groups, one of which was to be
treated with HuperzineA, the other to receive a placebo. In a
double-blind trial, one member of each pair, chosen randomly, was
given 100 micrograms of synthetic HupA twice daily for four weeks,
while the other member received the placebo. The students' memory
quotients were measured before and after the trial, and their
academic performance in their Chinese, English, and mathematics
lessons was monitored as well. At the end of the study, the
HuperzineA group scored significantly better than the control group
on standard memory tests described as "accumulation,"
"recognition," "reproduction," "association,"
"tactual [tactile] memory," and "number of
recitation," but not on tests of "picture memory" or
"understanding." They had also done significantly better in
their Chinese and English lessons, but not in math. No side effects
of any kind were noted (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's disease.
Acta Pharmacol Sin 1999 Jun;20(6):486-90).
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