Re: Cognitive-enhancing Effects of Bacopa in Healthy Adults
Stough C, Downey LA, Lloyd J, et al. Examining the nootropic effects of a special extract of Bacopa monniera [sic] on human cognitive functioning: 90 day double-blind placebo-controlled randomized trial. Phytother Res. 2008;22: 1629-1634.
Bacopa (Bacopa monnieri)—a traditional Ayurvedic
medicine with reported memory-enhancing, anti-inflammatory, analgesic,
antipyretic, sedative, and antiepileptic properties—contains many active
ingredients, including saponins, alkaloids, sitosterols, stigmasterols, d-mannitol, and betulic acid. The
memory-enhancing effects of bacopa extracts have attracted much attention and
have been attributed to 2 saponins: bacosides A and B. These saponins were
shown previously to facilitate avoidance response in rats and to reverse the
amnesic effects of neurotoxin, immobilization stress, scopolamine, and electroshock.
The mechanism responsible for the memory-enhancing effects of bacopa is
unknown; however, evidence suggests that it may be related to changes in
cholinesterase activity or to antioxidant effects (e.g., lipid peroxidation
chain action breaker). Although the results of animal studies, 2 single-blind
studies, and 1 double-blind placebo-controlled study support the
memory-enhancing effects of bacopa, additional studies are needed to confirm
the efficacy of this product and to determine the optimal dose before clinical
applications can be considered, which was the focus of the present study.
volunteers (n = 107) aged 18-60 years with no history of dementia, psychiatric
disorders, neurologic disease, chronic illness or infection, or endocrine, gastrointestinal,
or bleeding disorders were recruited for this double-blind, placebo-controlled
randomly assigned study. The subjects consumed either 2 capsules of placebo or bacopa
extract (KeenMind®; Keen Healthy Pty. Ltd.; India) twice daily for 90 days. The
extract was standardized for bacosides A and B (no less than 55% of combined
bacosides), and each capsule contained 150 mg of bacopa extract (20:1)
equivalent to 3 g of dried herb. The subjects completed a battery of cognitive
tests from the Cognitive Drug Research (CDR) computerized assessment system—designed
to assess 5 cognitive factor outcomes (speed and accuracy of attention, speed
of memory, accuracy of attention, secondary memory, and working memory)—at
baseline and after 90 days of supplementation with placebo or bacopa extract. Research
nurses monitored the subjects weekly for positive and negative symptoms
associated with treatment.
Of the 5
cognitive factor outcomes, only working memory improved significantly (P =
0.035) after treatment with bacopa. Specifically, performance on the Spatial
Working Memory task of the CDR improved significantly (P = 0.051) and
performance on the Rapid Visual Information Processing task of the CDR improved
significantly (P = 0.029) in the bacopa group. Over the 90-day treatment
period, the bacopa group reported a significantly greater incidence of diarrhea
and increased energy and a decrease in the number of dreams. The placebo group
reported a greater incidence of problems with their teeth and gums. None of the
other negative and positive symptoms reported were significantly different
between the 2 groups, which indicated that both treatments were
"reasonably well tolerated" by both groups.
treatment (90 days) with bacopa resulted in a significant improvement in some
of the tasks associated with working memory, whereas placebo treatment did not.
Although significant improvements in most of the tasks were not observed, the
results of many of the statistical analyses trended toward an improvement in
cognitive function in the areas of attention, working memory, and psychomotor
tasks. These results corroborate the findings of 2 previously published studies
that reported cognitive-enhancing effects of bacopa after 90 days of treatment.1,2
The authors conclude that additional studies are needed to "ascertain the
effective dosage range, time required to attain therapeutic levels and effects
over a longer term of administration."
—Brenda Milot, ELS
1Stough C, Lloyd J, Clarke J, et al.
The chronic effects of an extract of
Bacopa monniera [sic] (Brahmi) on cognitive function in healthy human
2Roodenrys S, Booth D,
Bulzoni S, Phipps A, Micallef C, Smoker J. Chronic effects of Brahmi (Bacopa monnieri) on human memory. Neuropsychopharmacology.