The method for producing a plant cell extract of hydroxyl rich glycoproteins (HRGP), including extensins, by extraction from plant cell walls (PCW), comprises subjecting a biomass of whole dedifferentiated plant cells to the following treatment : - Breaking the cells for producing a cell homogenate in which the intracellular molecules are solubilized; - Eliminating the solubilized intracellular molecules by washing the cell homogenate with water and diafiltering on a 0.2祄 filter; - Extracting the HRGP from the PCW by adding a salt thereby forming an HRGP enriched salted extract suspension; - Filtering the HRGP enriched salted extract suspension to discard the PCW debris and recover the desired enriched HRGP salted extract. Results on beautifying and on the general state of the skin and of its annexes can be observed with the use of the HRGP extracts according to the invention, in particular : on the texture (moisturising capacity is improved; skin is better protected against external aggressions); on the mechanical properties (skin is denser, replumped, firmer, more toned and more elastic); and on the complexion (skin is brighter).