I've been searching but couldn't find any information about the quantitative composition of the OTC dye henna. It is very interesting as it should bee 2-Hydroxy-1,4-naphthoquinone according to an old book, but I have no idea if the OTC product is a pure compound or some mixture. As you can see it is excellent precursor for the making of 2-methoxy analogue of 2C-G-N, it should bee active, don't you think so?

Well, I don't know if the information on 2-Hydroxy-1,4-naphthoquinone is correct, but henna is a brown-red plant material that my girlfriend usess to dye her hairs with. It is therefore not a pure compound, but if the concentration is high enough I guess you could extract the quinone, but it might bee difficult to purify.

Henna aka Lawsonia inermis

(http://reverndbunny.sphosting.com/growhenna.html)

Composition:

http://www.ars-grin.gov%3A8080/npgspub/xsql/duke/plantdisp.xsql?taxon=547

(change %3A in the above link into : to make it work)