maandag, januari 30, 2012
Nog eens wat over ginseng naar aanleiding van een recent overzichtsartikel.
Rond 1700 kwam de ginsengwortel Panax ginseng C. A. Meyer ("pan" = alle en "akos" = remedie) in de belangstelling in Europa en vonden rond de omstreden wonderplant de eerste wetenschappelijke uiteenzettingen plaats. Sindsdien hebhen westerse geleerden zich met wisselend succes op het onderzoek van de mysterieuze ginseng-wortel geworpen. Panax ginseng is na zes tot zeven jaar volgroeid en ziet eruit als een kleine struik met bladeren die in juli wit-rose bloemen krijgt en eind augustus begin september knalrode vruchten voortbrengen. De naam ginseng is rechtstreeks afgeleid van de Chinese benaming "'jen san", waarbij "jen" staat voor mens en "san"' plant betekent. Lees verder op http://dier-en-natuur.infonu.nl/bloemen-en-planten/30569-ginseng-het-energiekruid.html
Ginseng Is Safe and Effective for Certain Diseases and Conditions Lee N-H, Son C-G. Systematic review of randomized controlled trials evaluating the efficacy and safety of ginseng. J Acupunct Meridian Stud. 2011;4(2):85-97.
Ginseng (Panax spp.) has been reported to reduce physical, chemical, and biological stress, and increase general vitality and immune function. Its chemical constituents have been identified, with about 40 active ingredients (including ginsenosides, diacetylenes, sesquiterpenes, polysaccharides, and peptidoglycans) isolated. Randomized, controlled trials (RCTs) are being conducted to determine the clinical efficacy and safety of ginseng for patients with specific diseases or conditions. The objective of this clinical review was to further the proper use of ginseng by critically evaluating the evidence from RCTs on its efficacy and safety.
The authors conducted systematic literature searches of 13 databases up to March 2009 without any language restrictions. All RCTs evaluating the clinical effects or safety of the use of ginseng monopreparations (P. ginseng or P. quinquefolius) were considered.
Two authors extracted data from the articles by using a standardized, predefined method that considered trial methods, study design, patient characteristics, type of ginseng, outcomes, and side effects. By using the five-point Jadad scale to determine quality, the authors considered trials with three or more points to be of high quality.
The authors reviewed the RCTs to formulate conclusions on the effectiveness of ginseng for the following: glucose metabolism, physical performance, sexual function, psychomotor function, cardiac function, pulmonary function, and cerebrovascular function. Levels of evidence on the methodological quality and outcome of the studies ranged from Level 1 (strong evidence from generally consistent findings of multiple relevant, high-quality RCTs) to Level 4 (inconclusive evidence from only one relevant, low-quality RCT, no relevant RCTs, or RCTs with conflicting results).
The trials used two species of ginseng or a mixture of species: P. ginseng, including red ginseng (37 studies); P. quinquefolius (15 studies); and mixed ginseng types (five studies). The dosage ranged from 1 g to 9 g ginseng powder and from 0.2 g to 1.125 g ginseng extract daily.
Of the 12 studies reporting the effects of ginseng on glucose metabolism, 11 had good methodology. Of those 11, eight had positive results, two had negative results, and two yielded variable results. "Therefore, there was strong evidence to suggest that ginseng shows pharmaceutical properties for glucose metabolism," conclude the authors.
The efficacy of ginseng on physical performance was evaluated in nine trials of healthy subjects. The eight high-quality studies among those yielded negative results; therefore, say the authors, "Ginseng was not shown to enhance physical performance with strong evidence."
Five of the eight trials evaluating the efficacy of ginseng on psychomotor function using regular P. ginseng or its red ginseng displayed good methodology. Of the eight trials, six had positive findings and two had negative findings, indicating strong evidence of efficacy.
The methodology of six of the seven RCTs investigating the effects of ginseng on erectile dysfunction was of poor quality, according to the authors. The one high-quality trial revealed a negative result; positive results were reported in the low-quality trials. Therefore, "There was moderate evidence that ginseng has pharmaceutical properties in erectile dysfunction," state the authors.
Moderate evidence of the effects of ginseng on cardiac function or disease was reported: of the six studies, four had positive results, and two had negative findings. Three of the six studies were of high quality, two of which (from P. quinquefolius) exerted no significant effect, while the third, a proprietary extract of P. ginseng, increased QTc interval and decreased blood pressure.
Five of six trials on the effects or safety of ginseng on pulmonary diseases were of high quality, and all yielded positive findings, suggesting strong evidence that ginseng is effective in treating pulmonary function.
Two studies on the effects on cerebrovascular function showed positive results. Moderate evidence was reported, as only one of the studies was of high quality.
The authors conclude that ginseng is beneficial for glucose control, central nervous system function, prevention of acute pulmonary disease, and cerebrovascular function, but not for enhancing physical performance.
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En andere goede linken
http://apps.who.int/medicinedocs/en/d/Js2200e/19.html#Js2200e.19 WHO monografie