The invention relates in particular to a novel extract of the seeds of the Kniphofia uvaria plant, preferably obtained by bringing into contact with at least one cosmetically acceptable nonpolar solvent, in particular CO2 under supercritical conditions, or by mechanical pressing. The invention also relates to a cosmetic or dermatological composition comprising said extract. The invention also relates to a cosmetic or dermatological care method comprising the application of said composition for preventing or delaying the appearance of the signs of skin aging, modulating the reactivity of sensitive skin, or maintaining the barrier function of the skin.