Mark Hampson asked:
How does giant hogweed change skin and damage it?
Chris - Giant hogweed produces a chemical which is actually used to treat psoriasis, and that chemical is psorolene. Psorolene gets in through the skin. In fact, if you take it into the body, it goes all around the body and goes into pretty much every cell in the body. But itís a photosensitising agent which means that a cell that's got it in can absorb light of certain wavelengths, and it produces a toxic chemical when itís interacting with light, and that toxic chemical can kill the cell.
So, this is why, if you take it into your body or you get it into contact with your skin, the skin cells where the contact occurred become very photosensitive, and then when you go out into the open, there's enough ultraviolet light, just even at low levels on even a cloudy day to interact with the drug that's in the skin, damage cells in the skin and it gives you an exaggerated sunburn.
Thatís actually an interesting phenomenon because people have now been able to take that out of nature and apply it to a medical condition, psoriasis, in order to get rid of some of the psoriasis lesions by putting people in basically a sun bed, and a dose of psorolin into the sun bed, and the rapidly dividing cells are more sensitive than normal cells, and so they tend to die off faster. And so, thatís how you treat your psoriasis.