i talked to a woman that uses henna for her hair the other day. i think that is how henna is spelled

I tried one called Naturetint. It does have some chemicals in it, but is ammonia-free and I don't think it has the chemical in it you asked about. It worked well on my hair, but did seem to dry it out a bit more than conventional haircolor (which was a surprise). There's also a henna-based product called Silver to Gold. It is supposed to change grey hair to more of a golden color. You can find more info on these by google-ing them.

Hope this helps ya!