Scroll down the article they are talking about Tumeric a ingredient included in the curry powders.
Here is what I know on curry. I hope I got it right. The curry plant was originally used to make Indian curry. The British in charge of India at the time wanted to bring the curries of India home to Britain but the leaves didn't travel well. So the came up with a powder mixture to mimic the taste of curry. I don't think restaurants use curry powder in their curries. I don't use any in mine normally. I have a few Indian cook books and they all seem to have turmeric, coriander and cumin in them. Those ingredients are in most powders along with some other ingredients. Curry leaves are still used in India today. I am not sure what ingredients are used or not used in India.