Panax Ginseng

Panax ginseng (PG, Asian ginseng) is a popular traditional Chinese medicine in which the active ingredient is the ginsenosides. Numerous studies support Asian ginseng’s effectiveness at improving a person’s ability to withstand stress, improve work performance and quality, and enhance mental function. The herb has been reported to stimulate the hypothalamic-pituitary-adrenal (HPA) axis and increase the release of adrenocorticotropic hormone (ACTH) thus increasing adrenal hormone secretion. It also can counteract the shrinkage of the adrenal gland caused by corticosteroid drugs. In a recent in vitro study, it was found that Asian ginseng extract inhibited hydroxyl radical formation and they hypothesized that this antioxidant effect may be responsible for ginseng’s wide range of pharmacological uses (Ray et al, 2016).  Ginseng polysaccharides have anti-fatigue activity, also reflected in the effects on the physiological markers for fatigue (Wang et al, 2010).

Dioscorea oppositifolia

In this study, a 40% ethanol extract of Chinese yam flour (Dioscoreae rhizoma), containing 177 +/- 58 microg/mL of dioscin, was tested in order to evaluate its pharmacological effects on the gastrointestinal tracts of Sprague-Dawley rats. Via the ingestion of the Chinese yam extract, the secretion of gastric acid was suppressed in the rats, and gastrointestinal motility increased by as much as 10%. The faecal quantity of rats fed on the Chinese yam extract also increased, by more than 40% as compared with that of the controls. The Chinese yam extract was found not to affect the growth of normal intestinal bacteria. However, a great deal of lactose-fermenting bacteria was observed in the faecal samples of rats fed for 6 weeks on 2% Chinese yam extract. This finding would appear to suggest that Chinese yam extract not only induces an improvement in digestive capability, but also affects the conversion of some intestinal flora to helpful bacteria. Our serochemical analyses indicated that serum glucose, neutral lipid, and total cholesterol levels were reduced to some degree by long-term feeding on Chinese yam extract. This finding bolsters the notion that Chinese yam extract may prove helpful as a digestion-aiding agent for patients suffering from hyperglycaemia or hyperlipidaemia (Jeon et al, 2006).

Panax quinquefolius

This randomized, 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 standardized 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 et al, 2010).

Polygala tenuifolia

Roots of Polygala tenuifolia Willdenow have been used in humans for centuries because of its sedative effects. We previously reported that BT-11, extracted from the roots of the plant, improved memory impairments in rats, enhanced memory in normal humans, and inhibited acetylcholinesterase activities in vitro. The present study was a randomized, double-blind, placebo-controlled comparison study to investigate whether BT-11 could enhance memory in the elderly humans. We used the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (CERAD) and the Mini-Mental State Examination (MMSE). In the elderly, the total CERAD scores were much more significantly increased in the BT-11-treated group (n=28) than in the placebo-treated group (n=25). Especially, the mean scores of word list recognition, constructional recall and praxis, and modified Boston naming test were markedly improved in BT-11-treated group than in placebo-treated group. In conclusion, BT-11 could enhance some cognitive functions including memory in the elderly humans and therefore may be used as nutraceuticals that provide health benefits, including disease prevention and/or treatment (Shin et al, 2009).

Four weeks supplementation of BT-11 at 100mg (three times a day for a total dose of 300mg) in otherwise healthy middle-aged adults without cognitive impairment found that supplementation was able to increase immediate recall, recognition, and reduce errors in a spatial memory and organization test (SOPT) but it was ineffective for short and long term free and cued memory recall (K-CVLT) (Lee et al, 2009).

References

Lee JY, Kim KY, Shin KY, Won BY, Jung HY, Suh YH. Effects of BT-11 on memory in healthy humans. Neurosci Lett. 2009 Apr 24;454(2):111-4. doi:10.1016/j.neulet.2009.03.024. Epub 2009 Mar 11. PubMed PMID: 19429065.

Jeon JR, Lee JS, Lee CH, Kim JY, Kim SD, Nam DH. Effect of ethanol extract of  dried Chinese yam (Dioscorea batatas) flour containing dioscin on gastrointestinal function in rat model. Arch Pharm Res. 2006 May;29(5):348-53. PubMed PMID: 16756078.

Ray, A., K. Gulati, and R. Anand. "Stress, Adaptogens and Their Evaluation: An Overview." J Pharma Reports 1.110 (2016): 2.

Scholey, A., Ossoukhova, A., Owen, L. et al. Psychopharmacology (2010) 212: 345. doi:10.1007/s00213-010-1964-y. Effects of American ginseng (Panax quinquefolius) on neurocognitive function: an acute, randomised, double-blind, placebo-controlled, crossover study

Shin KY, Lee JY, Won BY, Jung HY, Chang KA, Koppula S, Suh YH. BT-11 is effective for enhancing cognitive functions in the elderly humans. Neurosci Lett. 2009 Nov 13;465(2):157-9. doi: 10.1016/j.neulet.2009.08.033. Epub 2009 Aug 20.

Wang J, Li S, Fan Y, Chen Y, Liu D, Cheng H, Gao X, Zhou Y. Anti-fatigue activity of the water-soluble polysaccharides isolated from Panax ginseng C. A. Meyer. J Ethnopharmacol. 2010 Jul 20;130(2):421-3. doi: 10.1016/j.jep.2010.05.027. Epub 2010 May 24. PubMed PMID: 20580802.