Radical‐Scavenging Activities of New Hydroxylated Ursane Triterpenes from cv. Annurca Apples

Two new ursolic acid triterpene derivatives, compounds 2 and 3 , have been isolated from cv. Annurca apple fruit, a high‐quality apple variety widely cultivated in southern Italy, together with the known 2‐oxopomolic acid ( 1 ). The new compounds were identified by means of different spectroscopic techniques as 3‐ epi ‐2‐oxopomolic acid (=(3 α )‐3,19‐dihydroxy‐2‐oxours‐12‐en‐28‐oic acid; 2 ) and (1 α )‐1‐hydroxy‐3‐oxours‐12‐en‐28‐oic acid ( 3 ). Compounds 1–3 were tested for their radical‐scavenging activities with the aid of a 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assay ( Fig. 2 ). All three constituents showed activities similar to that of the reference antioxidant α ‐tocopherol (vitamin E).