| abstract |
The invention relates to a method for dyeing human keratin fibres, comprising the application of a composition containing, in a cosmetically suitable medium, a vegetable extract including at least one compound having formula (I) as a dye precursor, or the addition salts thereof, combined with an external stimulus, selected from a heat, light or chemical stimulus produced using one or more organic and/or inorganic salts, in which formulae: R 1 represents a hydrogen, a methyl, a hydroxymethyl, an aldehyde, -CO 2 R 4 with R 4 representing a hydrogen or an alkyl at C 1 -C 2 , a sugar radical; R 2 represents a hydrogen, a hydroxyl, a sugar radical; R 3 , identical or non-identical, represent a hydrogen, a hydroxyl, an alkyl(C 1 -C 4 )oxy, the hydroxyl group number not exceeding 2; R represents a sugar radical; n is an integer between 1 and 5; the sugar radical originating from an aldose or an aldose derivative; the compounds having formula (I) having undergone, either prior to or simultaneously with the dyeing method, a step consisting in replacing radical R with a hydrogen atom. |