ABSTRACT The present invention relates to a method for preparing a concentrated spinach extract in liquid or dry form having a polyphenol titre equal to or greater than or equal 50 % including a step of purifying a raw spinach extract in liquid form using a liquid-liquid extraction technique with a food oilABSTRACT$!( Chapelles Sud Acti Parc de Pont de Vaux 01190 Reyssouze France France )