Wednesday, September 12, 2012

The Witch Hazel from which we get witch hazel

Species name: Hamamelis virginiana

Common name: Witch hazel

Location: Ontario

The witch hazel shrub was one of the very first woody plants that I learned how to identify in second year in an ecology course. I'm not sure why, of all "uncommon" plant species I managed to retain that one, but there it is. I use "uncommon" relatively; I knew, along with everyone else in the class, what a maple tree was, the difference between white and red oak, etc. This plant was one of the first I learned about that wasn't commonly spoken about by gardeners in my area. It could be because of it's characteristic relatively round leaves, and the uneven leaf base. I learned later that an uneven leaf base with nothing else to go on is actually incredibly common in the plant kingdom, and is a terrible single characteristic on which to base an identification! Witch hazel is a native plant across much of Canada (and North America in general), but has been naturalized in many parts of Europe and Australia. In the genus Hamamelis there are also a few species native to Asia in parts of China and Japan.

The uses of this shrub are many. The most famous use by far is as the main ingredient for the astrigent "witch hazel", which is obviously made from this plant. The leaves and young twigs are boiled down to extract the chemicals unique to the plant called hamamelitannins, which are chemically related to tannins found in oak galls (read about them HERE), walnut husks (read about them HERE), and in red wine. They have quite potent medicinal value, and have been used for centuries against swelling, superficial injuries, inflammation, and tumour suppression. It is also a very effective treatment for acne and other facial blemishes, and is a popular over-the-counter medication. It is also used to treat psoriasis, eczema, ingrown toenails, skin burns, poison ivy rashes, varicose veins and hemorrhoids. Whew!

Earlier this year the evidence that witch hazel extract is useful for tumour growth suppression was validated by a study jointly performed in Spain and the United States. They found that when the hamamelitannin extract was applied on colon cancer cells, it caused programmed cell death (an incredibly unusual phenomenon in cancer cells). When applied to a mixture of cancer cells and normal colon cells, only the cancerous cells were killed where the healthy ones survived. This is a very promising result, suggesting that this might one day be an incredibly effective treatment and cure for colon cancer. Clinical trials still need to be done on in vivo animal tissues, so there is still a very long time to wait for this to make it to the market, providing it is effective in the body and can be easily and practically administered.