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Steven Roodenrys, Ph.D.,
Dianne Booth, M.Sc.,
Sonia Bulzomi,
G.Dip.App.Psyc., Andrew
Phipps, G.Dip.App.Psyc.,
Caroline Micallef,
G.Dip.App.Psyc., and
Jaclyn Smoker,
G.Dip.App.Psyc.
A study is reported on
the effects of Brahmi (Bacopa
monniera) on human
memory. Seventy-six
adults aged
between 40 and 65 years
took part in a
double-blind randomized,
placebo control study in
which various
memory functions were
tested and levels of
anxiety measured. There
were three testing
sessions: one prior to
the trial, one after
three months on the
trial, and one six weeks
after the completion of
the trial. The results
show a significant
effect of the Brahmi on
a test for the retention
of new information.
Follow-up tests showed
that the rate of
learning was unaffected,
suggesting that Brahmi
decreases the rate of
forgetting of newly
acquired information.
Tasks assessing
attention, verbal and
visual short-term memory
and the retrieval of
pre-experimental
knowledge were
unaffected.
Questionnaire measures
of everyday memory
function and anxiety
levels were also
unaffected. [Neuropsychopharmacology
27:279–281, 2002]
KEY WORDS:
Psychopharmacology;
Memory; Herbal medicine;
Applied psychology;
Psychology; Short-term
memory
Brahmi (Bacopa monniera
Linn.) is a herb which
occurs naturally in
India and has a long
history of use in the
Ayurvedic medicine
tradition in the
treatment of a number of
disorders, particularly
those involving anxiety,
intellect and poor
memory (Singh and Dhawan
1997). It is currently
being marketed in
Western countries as a
memory enhancing agent.
Studies have shown that
the herb contains many
active constituents,
including a number of
alkaloids and saponins,
however, the major
constituents are the
steroidal saponins,
Bacosides A and B. There
are no published
scientific studies of
the effects of brahmi on
memory in humans;
however there are some
behavioral studies with
rats. These studies have
shown that it improves
the rate of learning in
a brightness
discrimination task and
a conditioned avoidance
task, that it improves
retention, as
demonstrated by savings
in relearning, and that
it attenuates amnesia
induced by
immobilization,
electroconvulsive shock
and scopolamine (Singh
and Dhawan 1997). This
latter finding involved
administration of the
extracted bacosides, A
and B, and suggests that
they influence
cholinergic systems.
Recently, however, it
has been reported that
brahmi has an
antioxidant effect in
the rat frontal cortex,
striatum and hippocampus
(Bhattacharya et al.
2000).
The aim of the current
study was to examine the
effects of an extract of
Bacopa monniera on
cognitive function.
Based on the behavioral
studies with rats,
described above,
it is expected that it
will improEighty-four
healthy volunteers who
were not taking any
medication or other
herbal preparation, and
reported
no head injuries,
commenced the study.
Eight participants
withdrew after the first
testing session, four
from each group. Only
one of these was due to
an adverse
(gastrointestinal)
reaction to the brahmi
capsules. Two of the
participants in the
placebo group withdrew
when they developed a
medical condition. At
the second testing
session and a mid-trial
telephone call
participants were asked
about their memory
function and given an
opportunity to make
other comments. On these
occasions no other
participants reported
adverse reactions.
Seventy-six participants
(28 males and 48
females) between the
ages of 40 and 65 years
(mean 49, S.D. 7),
completed the study.
Design
The study utilized a
double-blind, randomized
placebo controlled
independent group design
with two groups; a
Bacopa monniera (Keenmind
extract) group (n 37)
and a placebo group (n
39).
Procedure
Participants were tested
on three separate
occasions for
approximately one hour.
In the first session
pre-trial testing was
completed (baseline) and
the participants were
given three months
supply of capsules at
the dosage recommended
by the manufacturers
(300 mg for persons
under 90 kg, and 450 mg
for persons over 90 kg,
equivalent to 6g and 9g
dried rhizome,
respectively).
Participants were
contacted by telephone
approximately six to
eight weeks into the
trial period to
encourage compliance. A
second testing session
was conducted
approximately three
months later (3-month
test), at which
participants were
instructed not to take
any remaining capsules.
A post-trial testing
session occurred
approximately six weeks
after the end of trial
session.
At each testing session
a battery of tasks was
administered to assess
attention, a range of
memory abilities,
and psychological state.
The order of
administration of the
tasks was the same for
each session, and was as
follows:
A questionnaire about
everyday memory
performance (adapted
from Bennett-Levy and
Powell 1980); Immediate
recall of a short story;
Digit span — forward and
backward; A speeded
coding task involving
either
directly copying each
letter presented,
writing the next letter
in the alphabet or the
previous letter (as
described by Neubauer
and Knorr 1998); Delayed
recall of the short
story read earlier;
Three trials of learning
six unrelated word
pairs; A visual span
task requiring tapping a
sequence of blocks in
correct order – forward
and backward; A general
knowledge test of 20
questions (selected from
Nelson and Narens 1980);
Delayed recall of the
word pairs; The
Depression, Anxiety and
Stress Scale (Lovibond
and Lovibond 1995).
The mean scores for each
task are presented in
Table"
1. Preliminary - tests
showed no differences
between the two groups
at baseline on any
measures. The results
from all tasks were
analyzed by repeated
measures Analysis of
Variance (ANOVA) with
two factors,
Group (Brahmi and
placebo), and Testing
Session (baseline,
3-month, and post-trial)
as a within subjects
factor. The strongest
test of the hypothesized
effect of Brahmi is
provided by a planned
quadratic contrast
across Testing Session
interacted with the
Group factor.
The only measure to show
a significant effect was
the delayed recall of
word pairs task, F 1,74
4.932, p
.05. Follow-up analyses
using ANOVA showed
significant reduction in
performance between the
last learning trial and
the delayed recall test
in all three testing
sessions the group who
received the Brahmi
retained more word pairs
over the delay than the
placebo group.
DISCUSSION The results
show no significant
effect of chronic
administration of brahmi
on measures of
short-term memory,
working memory,
attention, or the
retrieval of information
from long-term memory
acquired
pre-experimentally.
Further, there were no
significant effects on
subjective measures of
psychological state
(depression, anxiety and
stress) or everyday
memory function. There
was a significant effect
on a task requiring the
retention of new
information: the recall
of unrelated word pairs
after a short delay.
There were no
significant differences
associated with the rate
of acquisition of the
information, as
evidenced by the lack of
a significant difference
between groups in the
learning trials. Rather
the effect appears to be
a reduction in the
amount of information
lost from memory. The
story recall task also
required participants to
learn some new material
and recall it a short
time later; however, it
did not show the same
significant effect. This
may be because there was
very little forgetting
of the material during
the delay, or because
story recall is a more
reconstructive process
than the recall of
unrelated word pairs (Baddeley
1990). The analyses were
not adjusted for
multiple measures, and
it should be
acknowledged that the
results may reflect a
Type I error. A further
limitation is that no
systematic attempt was
made to document any
adverse
reactions to the
capsules. There is
evidence of an
antioxidant effect of
Brahmi in the
hippocampus
(Bhattacharya et al.
2000). When combined
with the finding of
improved retention of
information in this
study, this suggests
that the effect of the
extract of Bacopa
monniera may be mediated
by antioxidant action
within the hippocampus.
ACKNOWLEDGMENTS
We would like to thank
Keenmind Pty Ltd for
supplying the Brahmi and
placebo for this study,
all of our participants,
and Pradeep Nathan and
two anonymous reviewers
for comments on drafts
of this article.
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