Research on The Color forming Property of Three Sulfur containing Iridoid glucoside from Paederia scandens (Lour) Merrill(Rubiaceae) with Amine containing Compounds I.Preparation of Iridoids,Color formation Condition and Property
Crosslinking coloration could undertake between iridoids and amine containing compounds,and this dyeing mechanism is basically different with all of those dyestuffs practiced at present.In this paper,three sulfur containing iridoids were prepared from Paederia scandens(Lour) Merrill(Rubiaceae),the reaction condition and the color forming mechanism of iridoids with amine containing compounds were investigated.The results indicated that:(1)For these sulfur containing iridoid glycosides,enzymatic hydrolysis and color forming reaction with methylamine could and must be carried out in one solution simultaneously.Further more,even without the presence of b glucosidase,color forming reaction could undertake between methylamine and paederoside or paederosidic acid methyl ester under mild acidic or basic solution.(2) The resultant color formed by each iridoid glycoside reacting with BSA and each protein fiber(e.g.,hide powder,silk and white hair) was the same as that formed by each iridoid glycoside reacting with methylamine.The result confirmed that,the molecular structure of iridoid compounds was the dominate factor for the resultant's color.(3) The mechanism of this color forming reaction might be that,the presence of methylamine had a cooperative effect with b glucosidase,sulfur containing iridoid glycosides were transferred to color intermediates,then the intermediates were polymerized to form colorants.