Effects of American ginseng (Panax quinquefolius) on neurocognitive function: an acute, randomised, double-blind, placebo-controlled, crossover study.
BACKGROUND
Over the last decade, Asian ginseng (Panax ginseng) has been shown to improve aspects of human cognitive function. American ginseng (Panax quinquefolius) has a distinct ginsenoside profile from P. ginseng, promising cognitive enhancing properties in preclinical studies and benefits processes linked to human cognition.


OBJECTIVE
The availability of a highly standardised extract of P. quinquefolius (Cereboost™) led us to evaluate its neurocognitive properties in humans for the first time.


METHODS
This randomised, double-blind, placebo-controlled, crossover trial (N = 32, healthy young adults) assessed the acute mood, neurocognitive and glycaemic effects of three doses (100, 200 400 mg) of Cereboost™ (P. quinquefolius standardised to 10.65% ginsenosides). Participants' mood, cognitive function and blood glucose were measured 1, 3 and 6 h following administration.


RESULTS
There was a significant improvement of working memory (WM) performance associated with P. quinquefolius. Corsi block performance was improved by all doses at all testing times. There were differential effects of all doses on other WM tasks which were maintained across the testing day. Choice reaction time accuracy and 'calmness' were significantly improved by 100 mg. There were no changes in blood glucose levels.


CONCLUSIONS
This preliminary study has identified robust working memory enhancement following administration of American ginseng. These effects are distinct from those of Asian ginseng and suggest that psychopharmacological properties depend critically on ginsenoside profiles. These results have ramifications for the psychopharmacology of herbal extracts and merit further study using different dosing regimens and in populations where cognition is fragile.
Scholey
Andrew
A
NICM Centre for the Study of Natural Medicines and Neurocognition, Brain Sciences Institute, Swinburne University, Melbourne, Vic 3122, Australia. andrew@scholeylab.com
Ossoukhova
Anastasia
A
Owen
Lauren
L
Ibarra
Alvin
A
Pipingas
Andrew
A
He
Kan
K
Roller
Marc
M
Stough
Con
C
D000293:Adolescent; D000328:Adult; D000339:Affect / Q000187:drug effects; D001786:Blood Glucose / Q000187:drug effects; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects*; D005894:Panax / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects; D013997:Time Factors; D055815:Young Adult
D001786:Blood Glucose; D010936:Plant Extracts