The antioxidants of the osage orange fruit

Summary The fruit of the osage orange tree (Maclua pomifera [Raf.] Schneider) was shown to contain at least four pigments with antioxidant activity. Pomiferin was present as 3 to 4% of the dry fruit and, as a primary antioxidant, was responsible for 20–25% of the activity exhibited by methanol extracts. An unidentified substance was also present which reacted synergistically with pomiferin, increasing its contribution to the overall activity to approximately 75%. The three new pigments, totalling 0.5% to .75% of the dry fruit, all showed antioxidant activity exceeding that of pomiferin when tested at equal concentrations. A chromatographic procedure, employing anhydrous magnesium sulfate, was developed and applied successfully in separating mixtures of several iso‐flavone pigments.