关于金缕梅的收敛性和抗氧化性的解释

最近看到一篇非常好的文章，是从wiki的reference找到的，解释了金缕梅的超强的收
敛性和抗氧化性，大家有兴趣可以看看：）更加坚定了我继续用金缕梅水水。。。。

节选自：Steven Foster Group article
http://www.stevenfoster.com/education/monograph/witchhazel.html

=================================
What make it work?

Depending upon how a preparation is made witch hazel products contain varying amounts of active compounds such as flavonoids, tannins (hamamelitannin and proanthocyanidins), small amounts of volatile oil, and other components, which may be responsible for its astringent action and to stop bleeding. Tannins have been characterized as hamamelitannin and a number of proanthocyanidins. The bark contains 31 times more hamamelitannin than the leaf extract, so place part used in preparation is important. In distilled witch hazel products much of the tannin content is lost.

A recent study shows there may be more at work in witch hazel than has been previously known. A specially filtered fraction of the extract, containing mostly proanthocyandins, was found to have significant anti-viral activity against Herpes simplex virus type 1. The same fraction was also found to have a strong antiphlogistic (inflammation-reducing) effect. In contrast, fractions high in hamamelitannin were found to have weaker antiviral or antiphlogistic activity. The significant of this study is that it shows that compounds other than tannins may play a role in witch hazel's recognized antiphlogistic effects, as well as newly recognized topical antiviral activity. Such studies serve to improve products available to consumers by helping manufacturers refine extraction processes to enhance the best possible therapeutic results.

Antioxidant, radiation-protective, and anti-inflammatory activity have been confirmed. Recently hamamelitannin and proanthocyanidins isolated from witch hazel were evaluated for their mechanisms of action in reported anti-inflammatory activity. It was found that some proanthocyanidin fractions inhibit inflammatory mediators derived from arachidonic acid and inhibited the formation of platelet-activation factor, a chemical mediator of inflammatory processes. When it is quelled, so is inflammation.

Strong antioxidant activity against superoxide (a highly reactive form of oxygen), released by several enzymes during the inflammatory process may also play a role in witch hazel's anti-inflammatory effects. In a recent study, Japanese researchers sought plant compounds that protect cells in skin tissue from damage against harmful forms of oxygen. Witch hazel was
found to have strong activity against reactive oxygen in skin tissue. The scientists proposed that witch hazel extracts should be further researched for their potential application in anti-aging or anti-wrinkling products to apply to the skin. Sounds like my grandmother was directing the study!