Effects and mechanisms of ginseng and ginsenosides on cognition

• Published in: Nutrition reviews 2014-05, Vol.72 (5), p.319-333
• Main Authors: Smith, Imogen, Williamson, Elizabeth M, Putnam, Sophie, Farrimond, Jonathan, Whalley, Benjamin J
• Format: Article
• Language: English
• Subjects: attention; Biological and medical sciences; clinical trials; cognition; Cognition & reasoning; Cognition - drug effects; Cognition - physiology; Cognition Disorders - drug therapy; Effects; Feeding. Feeding behavior; Functional foods & nutraceuticals; Fundamental and applied biological sciences. Psychology; ginseng; ginsenoside; ginsenosides; Ginsenosides - pharmacology; Humans; memory; Neurological disorders; Neuroprotective Agents - pharmacology; neuroprotective effect; Panax; Panax - chemistry; patients; pharmacokinetics; Pharmacology; Phytotherapy; Plant Extracts - pharmacology; Sapogenins - pharmacology; Vertebrates: anatomy and physiology, studies on body, several organs or systems; volunteers
• ISSN: 0029-6643; 1753-4887
• DOI: 10.1111/nure.12099

Reviewed here is the existing evidence for the effects of ginseng extracts and isolated ginsenosides relevant to cognition in humans. Clinical studies in healthy volunteers and in patients with neurological disease or deficit, evidence from preclinical models of cognition, and pharmacokinetic data are considered. Conditions under which disease modification may indirectly benefit cognition but may not translate to cognitive benefits in healthy subjects are discussed. The number of chronic studies of ginseng effects in healthy individuals is limited, and the results from acute studies are inconsistent, making overall assessment of ginseng's efficacy as a cognitive enhancer premature. However, mechanistic results are encouraging; in particular, the ginsenosides Rg₃, Rh₁, Rh₂, Rb₁, Rd, Rg₂, and Rb₃, along with the aglycones protopanaxadiol and protopanaxatriol, warrant further attention. Compound K has a promising pharmacokinetic profile and can affect neurotransmission and neuroprotection. Properly conducted trials using standardized tests in healthy individuals reflecting the target population for ginseng supplementation are required to address inconsistencies in results from acute studies. The evidence summarized here suggests ginseng has potential, but unproven, benefits on cognition.