Issue:
99
Page: 26-27
Acute Dose of Bacopa Extract Improves Cognitive Performance
by Heather S. Oliff, PhD
HerbalGram.
2013; American Botanical Council
Reviewed: Downey LA, Kean J, Nemeh
F, et al. An acute, double-blind, placebo-controlled crossover study of 320 mg and 640 mg doses of a special
extract of Bacopa monnieri (CDRI 08)
on sustained cognitive performance. Phytother
Res. December 2012; [epub ahead of print]. doi: 10.1002/ptr.4864.
In Ayurvedic traditional medicine in India, Brahmi or bacopa (Bacopa monnieri,
Scrophulariaceae) is a valued memory-enhancing, anti-amnesic, anxiolytic,
sedative, and anti-epileptic treatment. Modern in vitro and in vivo
studies have provided evidence suggesting several possible mechanisms for these
effects. Over a dozen clinical trials have documented the positive effects of
bacopa preparations (usually extracts) on learning, memory, information processing speed, and anxiety, as well as its antidepressant and cardiovascular
effects. However, the majority of clinical trials have investigated the effects
of chronic bacopa treatment; to date only one study has assessed its acute nootropic or cognitive-enhancing effects. The purpose of this double-blind,
placebo-controlled, crossover clinical trial was to evaluate the effects of two
dosage levels of special bacopa extract on mood, cardiovascular activity, and
cognitive performance.
Healthy volunteers (n=24; aged 18-56 years, with a body mass index of 15.4-32.7 kg/m2) participated in
this study conducted in Australia. Pre-screening exclusion criteria were as
follows: smoking; any history of psychiatric disorders or neurological diseases; endocrine, gastrointestinal, or bleeding disorders; chronic illness
and infection; pregnancy or lactation; and current use of medications or herbal
supplements.
Subjects received a single acute dose of placebo (four 160 mg capsules of inert plant-based materials), 320 mg,
and 640 mg of bacopa extract (KeenMind® [CDRI 08]; SFI Flordis; St.
Leonards, NSW, Australia) in a three-arm crossover design. Each treatment was
separated by a one-week washout period. The 50% ethanol bacopa extract was prepared from stems, leaves, and roots of a cultured variety of bacopa
collected from West Bengal, India, and standardized to 55% total bacosides.
Each subject attended four assessment sessions — one practice visit and three study visits. On each study
visit, tests were conducted prior to the acute dose (baseline) and then two
hours after dosing. The tests included a cognitive demand battery (CDB) and
assessments of blood pressure, arterial stiffness, and cerebral blood flow. The
CDB was comprised of a subjective assessment of stress and mental fatigue on a
visual analogue scale (VAS), serial threes and serial sevens subtraction tests
(counting backward from a given number by threes or sevens), and the Bakan
Rapid Visual Information Processing (BRVIP) task (identifying three consecutive
series of odd or even numbers in a random series, evaluated for both accuracy
and reaction time). Each CDB took 10 minutes and was conducted seven times per
visit; one test before ingestion of the study medication and then six
continuous tests starting two hours after ingestion.
Compared with placebo, 320 mg of this bacopa extract significantly improved performance of the serial threes
subtraction test at the first (P=0.05) and fourth repetition (P=0.02). For all
groups, there was a significant improvement over time on the serial threes test
(P<0.001). There were no other significant findings for the serial threes
test.
For the serial sevens subtraction
test, the only significant change was an improved performance of the 640 mg
dose of bacopa extract compared with the 320 mg dose at the first repetition
(P<0.05). For all groups, there was a significant improvement over time on
the serial sevens test (P<0.001).
There were no significant changes in
the BRVIP task. The CDB significantly increased the subjective ratings of
stress and fatigue (P<0.01); none of the treatments attenuated these
effects. There were no significant changes in the cardiovascular assessments,
and no adverse events occurred.
The authors hypothesize that greater
cognitive enhancement could have occurred prior to the two-hour post-treatment
assessment, which may explain why the improvements took place during the
earliest repetitions. The authors conclude that the acute nootropic effect of
this bacopa extract may be limited to early windows of activity (i.e., < two hours post-dosing).
It cannot be ruled out that any
statistical significance may be due to chance, since there were six post-dosing
tests conducted, and few showed any alterations. Another point to consider is
that not all extracts are created equally, and other bacopa extracts may behave
differently in this paradigm.
—Heather S. Oliff, PhD
|