Abstract: The invention relates to a method and a system (1) of pre-treating biomass (2), in particular biomass (2) that is resistant to cell disruption, for improving the accessibility of a compound therefrom.The inventions further relates to a method for extracting a compound from a biomass (2), in particular a biomass (2) that is resistant to cell disruption, comprising the steps of pre-treating the biomass (2) and extracting the compound from the pre-treated biomass (2). In order to improve the extraction of compounds from biomass (2) that is resistant to cell disruption, the inventive method comprises the step of incubating the biomass (2) in plasma activated water (4). The inventive system (1) comprises a plasma activated water stage (3) configured to incubate the biomass (2) in plasma activated water (4); and an electric field stage (5) comprising at least one capacitor (6) for generating and applying an electric field to the biomass (2).