5 replies to this topic

[crassus]

I just came across a new study showing that American ginseng improves working memory in healthy young adults (at all dosages, 1 to 6 hours afterwards ... almost to good to be true). Unfortunately I'm not too experienced at interpreting the significance of such a study. Can somebody comment?
Any anecdotal reports on American ginseng?

http://www.ncbi.nlm....pubmed/20676609

Effects of American ginseng (Panax quinquefolius) on neurocognitive function: an acute, randomised, double-blind, placebo-controlled, crossover study.

Abstract

RATIONALE: 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. OBJECTIVES: 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.

[aLurker]

I skimmed through the report, looked pretty ok on the surface. They mention this at the end though:

Acknowledgement This work was supported by a grant from Naturex Inc.

They are sponsored by the company and they mentioned their product by name several times in the study although this doesn't invalidate the science behind the study if they performed it correctly.

Anyone with more experience reading such studies are welcome to look further into this.

[meursault]

I think that the best advice I can give you is to not base the activity or effects of a drug, herb, etc. on the conclusions of a single study. Several studies, especially those without a high probability of experimental bias (presence of corporate sponsorship), are necessary to determine, with great certainty, the effects of a compound.

Edited by czukles, 10 August 2010 - 03:07 PM.

[aLurker]

Anyone taking this? I mean it's very cheap (especially at 100-200 mg), safe, stacks well, has at least one placebo controlled study backing it and could potentate stims as we've discussed briefly in the bacopa thread. Looks like it has potential so why haven't more of us tried it?

Here is the full study mentioned by the OP.

Edited by aLurker, 22 November 2010 - 03:59 PM.

[solracselbor]

Anyone taking this? I mean it's very cheap (especially at 100-200 mg), safe, stacks well, has at least one placebo controlled study backing it and could potentate stims as we've discussed briefly in the bacopa thread. Looks like it has potential so why haven't more of us tried it?

Here is the full study mentioned by the OP.

I just glanced over the study. I didn't see any means or standard deviations, so I can't really estimate the meaningfulness of the results. I have never seen numeric working memory measured using a cued choice task, nor does it site any studies showing its reliability and validity in measuring working memory for that matter. Also, consider the word presentation task:

Word presentation Words matched for linguistic familiarity, concreteness and frequency were drawn from http://www.math.york...S/Online/paivio. Individual words were presented sequentially on the monitor. Stimulus duration was 1 s, as was the inter-stimulus interval.Immediate word recall The participant was allowed 60 s to write down as many of the words as possible. The task was scored for number of correct answers, errors and intrusions and the resulting score was converted into a percentage.

This was found to be significant, however the study does not state the frequency of words used. Was it enough to actually involved the use of working memory, or was it simply passive? Like I said, means and SD's would be nice.
What I found really crazy, and completely unrelated to the methodology, was the notion of a potential for ginseng inducing nitric oxide:

Previous research in rodents has shown that Ginseng saponins and Ginsenoside Rb1 inhibit the stress-induced increases in plasma corticosterone (Kim et al. 1998a,b; Luo et al. 1993) later found that this inhibitory action of Ginseng was blocked by a co-administered inhibitor of nitric oxide (NO) synthase, suggesting that ginsenosides may modulate the stress-induced hypothalamus–pituitary–adrenal response by inducing NO production in the brain.

Based on this thread ( http://www.imminst.o...6-pramiracetam/) I would assume that's a bad thing.

[atrollappears]

I just glanced over the study. I didn't see any means or standard deviations, so I can't really estimate the meaningfulness of the results. I have never seen numeric working memory measured using a cued choice task, nor does it site any studies showing its reliability and validity in measuring working memory for that matter.

Um what exactly do you mean by "cued choice task"? The tests seem fairly standard for measuring working memory, or at least similar to the working memory tests I did in WAIS.

Also, consider the word presentation task:
...
This was found to be significant, however the study does not state the frequency of words used. Was it enough to actually involved the use of working memory, or was it simply passive? Like I said, means and SD's would be nice.

Yes it does... it says they are displayed for 1 second and 1 second apart. That's a pretty standard frequency for testing working memory.

What I found really crazy, and completely unrelated to the methodology, was the notion of a potential for ginseng inducing nitric oxide:

Previous research in rodents has shown that Ginseng saponins and Ginsenoside Rb1 inhibit the stress-induced increases in plasma corticosterone (Kim et al. 1998a,b; Luo et al. 1993) later found that this inhibitory action of Ginseng was blocked by a co-administered inhibitor of nitric oxide (NO) synthase, suggesting that ginsenosides may modulate the stress-induced hypothalamus–pituitary–adrenal response by inducing NO production in the brain.

Based on this thread ( http://www.imminst.o...6-pramiracetam/) I would assume that's a bad thing.

Nitric oxide is one of the main redox signaling agents in the body. Just that NO has to be present for something to happen does not mean that that thing is the result of changes in NO. For example, NO is necessary for amphetamine's behavioral effects, yet amphetamine does not act by inducing NO synthesis (I'm pretty sure NO is not required for uptake or transporter phosphorylation). Rather, NO is an important signaling molecule in the regions of the brain affected by amphetamine, IIRC.

Also, according to these studies, if ginseng does anything it decreases nitric oxide production:
http://www.sciencedi...014488603004060
https://www.thieme-c...055/s-2000-8624
http://www.sciencedi...165572809000253
http://ginsengres.or...ENG/138-144.pdf
http://bemri.com/app...sorders (1).pdf