A method for preparing a composition, comprising a) reducing mother-of-pearl into powder with grain size distribution ranging between about 1 and about 300 m; b) placing the obtained powder in close contact with an extracting agent in the form of a hydroglycol solution of at least a collagen, of at least a proteoglycan or a mixture thereof; then c) in collecting the extraction mixture, formed by the close contact, constituting the desired composition. The composition obtainable by said method has very interesting properties relative to the skin and/or skin appendages, in particular tissue-regenerating properties, enabling for instance improved wound healing, and anti-ageing properties for preventing and/or visibly reducing effects related to skin and/or skin appendage ageing.