Investigations Towards the Binding Mechanisms of Vegetable Tanning Agents to Collagen

Background: The mechanism of interaction of vegetable tanning agents with skin collagen is hardly predictable due to the variability of chemical interactions of the vast number of different substance classes.Objective: In the present study it was aimed to apply less extensive methods to classify the mechanism of the cross linking action of vegetable agents with non-soluble collagen.Methodology: Hide powder was treated with solutions of different vegetable tanning agents at different pH values.The cross linking effect was analysed with DSC measurements of denaturation temperature, determination of bound amine groups before and after acidic hydrolysis and resistance against enzymatic proteolytic attack.Results: In this study a high number of common vegetable tanning extracts was analysed and classified according to the mode of interaction in three different groups: Ionic (reversible interaction), covalent non-acid-resistant and covalent acid-resistant interaction.Moreover, the tanning action of new plant extracts of common wide spread plants like privet leaf could be identified.Conclusion: The right combination of a limited number of analytical methods is sufficient to characterise the reaction mechanism of tanning agents with collagen material.