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- Korean White Ginseng (Panax ginseng)
- Alzheimer's Disease
- Cognitive Performance
| Date: 11-14-2008 | HC# 100381-364 |
Re: Korean White Ginseng Improves Cognitive Performance in Patients With Alzheimer's Disease
Lee S-T, Chu K, Sim J-Y, Heo J-H, Kim M. Panax ginseng enhances cognitive performance in Alzheimer disease. Alzheimer Dis Assoc Disord. September 2008;22(3): 222-226.
The modern pharmacologic effects of ginseng and its
components, ginsenosides, have been demonstrated in the cardiovascular,
endocrine, and immune systems.1 Also, ginseng has been reported to
increase the cognitive performance of healthy persons.2-5 For Alzheimer's
disease, investigators have examined the neuroprotective and tropic effects of
ginseng in experimental models. These authors report on their investigation of
Korean white ginseng's (Panax ginseng)
effect in enhancing the cognitive function in patients with Alzheimer's
disease.
They conducted a prospective, open-label study at the Seoul National
University Hospital
in South Korea
from June 2004 until October 2005. Ninety-seven patients who met NINDS-ADRDA
(National Institute of Neurological Disorders and Strokes, and Alzheimer's
Disease and Related Disorders Association) criteria for probable Alzheimer's
disease were included (aged 47 to 83 years).
The authors excluded patients who had evidence of other
neurodegenerative disorders or cognitive impairments resulting from acute cerebral
trauma, dysthymia, hypoxic cerebral damage, vitamin deficiency, infection,
cerebral neoplasia, metabolic disease, mental retardation, oligophrenia, or a
coexisting medical condition that could prevent them from completing the study.
The patients were randomly assigned to the ginseng group
(n=58; 20 men and 38 women) or to the control group (n=39; 15 men and 24
women). The ginseng group was treated with Korean white ginseng powder (4.5 g/d
of 6-year-old Panax ginseng roots from Hongcheon and Heongsung provinces
in South Korea, powdered and encapsulated by Nonghyup Co., South Korea) for 12
weeks. According to the authors, the ginseng contained total 8.19% of
ginsenosides, plus essential oils, diacetylenic compounds, acidic
polysaccharides, phenolic compounds, peptidoglycans, amino acids, vitamins, and
carbohydrates.
To evaluate possible dose-response effect, an additional 9
patients were administered a higher dose of ginseng (9 g/d).
After the 12-week period of ginseng treatment, the patients
were monitored for another 12 weeks.
To evaluate cognitive functions, the authors used scores on
the mini-mental state examination (MMSE) and Alzheimer's disease assessment
scale (ADAS), including the ADAS cognitive subscale (ADAS-cog) and noncognitive
subscale (ADAS-noncog). Efficacy variables included changes of MMSE and ADAS
from baseline scores at 4, 12, and 24 weeks after the start of treatment.
The authors report that efficacy analyses were primarily
preformed on an intention-to-treat (ITT) basis; a per-protocol analysis was
also done. Intergroup comparisons for changes from baseline in ADAS and MMSE
scores were performed using the Student's t test. They used repeated
measures analysis of variance to compare the raw MMSE and ADAS scores in
addition to the comparison of the changes from baseline. The frequencies of
side effects and withdrawn patients were compared by using chi-square test. All
P values are two-tailed; statistical significance was accepted for P values
<0.05.
At 4 weeks, 91 patients (54 in the ginseng group, 37 in the
control group) were reevaluated and included in the efficacy analysis.
Eighty-two patients (50 in the ginseng group, 32 in the control group)
completed 12 weeks of treatment, and 58
patients (ginseng group, 36; control group, 22) were reevaluated at 24
weeks after the treatment began.
Baseline characteristics including age, sex, ADAS cog,
ADAS-noncog, MMSE and clinical dementia rating scale scores were similar
between the 2 groups.
The authors report improved MMSE scores in the ginseng group
on the efficacy analysis. At 4 weeks, the ginseng group showed an improvement
in MMSE score by 1.0 ± 2.4 points from the baseline, whereas the control group
changed by –0.58 ± 2.4 points (P = 0.033 between the 2 groups). At 12 weeks, the
ginseng group improved by 1.8 ± 2.8 points, whereas the control group changed
by only –0.03 ± 3.1 (P = 0.009 between the 2 groups). However, after the
12-week period of ginseng discontinuation, no difference was observed between
the 2 groups (control = 0.88 ± 2.5, ginseng = 0.56 ± 3.6, P = 0.673).
ADAS-cog scores were also improved in the ginseng group at 4
weeks and at 12 weeks after the ginseng treatment compared with the control
group on ITT basis. And, again, after the ginseng had been discontinued for 12
weeks, the differences between the ginseng and control groups disappeared.
In contrast, say the authors, the ADAS-noncog scores, which
represent neuropsychiatric symptoms, showed no significant difference between
the ginseng and control groups on ITT basis at 4 weeks, 12 weeks, or at 24
weeks.
According to the authors, the repeated measures analysis of
variance revealed that at 4 weeks, the ginseng group showed an improvement in
ADAS-cog score compared with the control group after adjusting the baseline
values. At 12 weeks, the ginseng group showed improvements in both ADAS-cog and
MMSE scores after adjusting the baseline values.
The ADAS-cog and ADAS-noncog and MMSE changes for the 9
patients treated with 9 g/d of the ginseng powder for 12 weeks were not
different compared with those treated with 4.5 g/d of ginseng.
Adverse events (reported by 7 of the 58 patients in the
ginseng group and 6 of the 39 patients in the control group) were mild and
transient.
Among the limitations of this study are the small number of
patients involved, the short duration, and the fact that because this was an
open-label study, the effect of the ginseng was not relative to a placebo.
According to the authors, these results suggest that Korean white ginseng is clinically
effective in the cognitive performance of patients with Alzheimer's disease and
that longer-term, placebo-controlled, double-blinded studies are warranted.
―Shari Henson
References
1Attele AS, Wu JA, Yuan CS.
Ginseng pharmacology: multiple constituents and multiple actions. Biochem
Pharmacol. 1999;58:1685-1693.
2Kennedy DO, Scholey AB.
Ginseng: potential for the enhancement of cognitive performance and mood. Pharmacol
Biochem Behav. 2003;75:687-700.
3D'Angelo L, Grimaldi R,
Caravaggi M, et al. A double-blind, placebo-controlled clinical study on the
effect of a standardized ginseng extract on psychomotor performance in healthy
volunteers. J Ethnopharmacol. 1986;16:15-22.
4Sorensen HSJ. A double
masked study of the effects of ginseng on cognitive functions. Curr Ther Res.
1996;57:959-968.
5Kennedy DO, Scholeya AB,
Wesnes KA. Dose dependent changes in cognitive performance and mood following
acute administration of ginseng to healthy young volunteers. Nutr Neurosci.
2001;4:295-310.
Editor's Note: It is rather curious that this Korean
research group has published a parallel study with Korean red ginseng (see HC
090381.362), but neither that publication nor the one here reviewed cite the
other. The two manuscripts were received by the respective journals on
September 11 and November 14, 2007. Unexpectedly, there seems to have been no
significant difference in effectiveness between white and red ginseng, whereas
the latter would have been expected to be superior. The efficiency of
conversion from white to red bears investigation. |