Ginkgo biloba extract for age-related macular degeneration

 

Abstract

Background

Ginkgo is used in the treatment of peripheral vascular disease and 'cerebral insufficiency'. It is thought to have several potential mechanisms of action including increased blood flow, platelet activating factor antagonism, and prevention of membrane damage caused by free radicals. Vascular factors and oxidative damage are thought to be two potential mechanisms in the pathology of age-related macular degeneration (AMD).

Objectives

The objective of this review was to determine the effect of Ginkgo biloba extract on the progression of AMD.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2008, Issue 4), MEDLINE (January 1966 to December 2008), EMBASE (January 1980 to December 2008), OpenSIGLE (1980 to December 2008), AMED (January 1985 to December 2008), UK Clinical Trials Gateway (December 2008), reference lists of identified trial reports, and the Science Citation Index. We also contacted investigators of included studies for additional information.

Selection criteria

All randomised trials in people with AMD where Ginkgo biloba extract had been compared to control were included.

Data collection and analysis

The review author extracted data using a standardised form. The data were verified with the trial investigators. Trial quality was assessed.

Main results

Two published trials were identified. However, these trials were small (20 and 99 participants) and their results could not be pooled because they had different comparisons. Adverse effects and quality of life for people with AMD were not reported.

Authors' conclusions

The question as to whether people with AMD should take Ginkgo biloba extract to prevent progression of the disease has not been answered by research to date.

 

Plain language summary

Use of Gingko biloba, an extract from the leaves of the maidenhair tree, for slowing the progression of age-related macular degeneration

Age-related macular degeneration (AMD) is a condition affecting the central area of the retina (the back of the eye). The retina can deteriorate with age and some people get lesions that lead to loss of central vision. Gingko biloba, extracted from the leaves of the maidenhair tree, is used in Chinese herbal medicine to treat a variety of medical conditions, in particular circulatory problems. Ginkgo biloba extract contains two constituents (flavonoids and terpenoids) which have antioxidant properties. It is believed these may help to slow down the progression of AMD. The author identified two small randomised controlled studies (with a total of 119 participants); one in France and one in Germany. One trial compared Gingko biloba to placebo and the other compared two different doses of the extract. Although both trials reported some positive effects of Ginkgo biloba on vision, the trials were small and of short duration. Adverse effects and quality of life were not assessed. The overall conclusion of this review is that current research has not answered the question as to whether Ginkgo biloba is of benefit to people with AMD.

 

摘要

背景

銀杏萃取液(Ginkgo Biloba extract)對於老年性黃斑部病變(agerelated macular degeneration, AMD) 的功效

銀杏一直被用來治療周邊血管疾病和“大腦缺失”. 是因為被認為它有增加腦部循環,血小板活化因子阻抗劑以及防止細胞膜受自由基的傷害等潛在機制. 而血管因子和氧化物的傷害是被認為造成AMD的可能機制.

目標

以客觀性的回顧銀杏萃取液對於老年性黃斑部病變之疾病進程的影響

搜尋策略

我們搜尋Cochrane Central Register of Controlled Trials (CENTRAL)包含Cochrane眼睛和視力類試驗登錄,在The Cochrane Library 2005年第四版, MEDLINE(1966年至2006年1月,第三週), EMBASE (1980年至2006年1月), SIGLE (1980年至2005年3月), AMED (1985年至2006年1月), NRR (2005年第四版),確定試驗報告的參考文獻以及科學引證索引.我們也跟納入研究的觀察者聯繫以獲取額外的訊息

選擇標準

所有AMD的病人都以隨機試驗下,以銀杏萃取液和控制組做比較

資料收集與分析

這做回顧的作者引用的數據皆使用標準化的形式. 而數據也是由試驗的研究員確認無誤. 另外試驗的品質也已被評定

主要結論

兩個已出版的試驗已被確定。然而，這些試驗是小(20和99人參加) ，其結果無法集中，因為他們有不同的對照組。另外不良反應和人們的生活品質與AMD之間關係還沒有得到解決。

作者結論

至於是否有AMD的人?應該採取Ginkgo Biloba Biloba萃取物來防止疾病演進的問題,迄今未由研究能回答

翻譯人

本摘要由高雄榮民總醫院洪碧蓮翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

Gingko Biloba,從公孫樹的葉子的一種萃取物,藉由影響視網膜的中央部位(眼球後方)來減緩AMD的病程. 視網膜會因老化和某些人因受傷而導致視力的喪失. Gingko Biloba,從公孫樹的葉子的一種萃取物,在中藥上一直被用來各種醫療上的疾病特別是血液循環的問題上.銀杏萃取液包含兩種組成物flavonoids黃酮類和terpenoids皆含有抗氧化的特質. 而這些被相信可用來減緩AMD的病程. 作者確認了兩組隨機控制的研究(119參與者);一篇在法國一篇在德國.一篇是用銀杏萃取液和安慰劑做比較,一篇是比較兩個不同的劑量. 雖然這兩個試驗報告顯示一些正面的影響銀杏的設想，試驗仍屬小型和短期。總括結論是這次審查，目前的研究並沒有回答是否銀杏有利於AMD的人們之問題，而仍需要進一步研究。